The viral distribution and pathological characteristics of BALB/c mice infected with highly pathogenic Influenza H7N9 virus.

BACKGROUND: The highly pathogenic Influenza H7N9 virus is believed to cause multiple organ infections. However, there have been few systematic animal experiments demonstrating the virus distribution after H7N9 virus infection. The present study was carried out to investigate the viral distribution and pathological changes in the main organs of mice after experimental infection with highly pathogenic H7N9 virus. METHODS: Infection of mice with A/Guangdong/GZ8H002/2017(H7N9) virus was achieved via nasal inoculation. Mice were killed at 2, 3, and 7 days post infection. The other mice were used to observe their illness status and weight changes. Reverse transcription polymerase chain reaction and viral isolation were used to analyse the characteristics of viral invasion. The pathological changes of the main organs were observed using haematoxylin and eosin staining and immunohistochemistry. RESULTS: The weight of H7N9 virus-infected mice increased slightly in the first two days. However, the weight of the mice decreased sharply in the following days, by up to 20%. All the mice had died by the 8th day post infection and showed multiple organ injury. The emergence of viremia in mice was synchronous with lung infection. On the third day post infection, except in the brain, the virus could be isolated from all organs (lung, heart, kidney, liver, and spleen). On the seventh day post infection, the virus could be detected in all six organs. Brain infection was detected in all mice, and the viral titre in the heart, kidney, and spleen infection was high. CONCLUSION: Acute diffuse lung injury was the initial pathogenesis in highly pathogenic H7N9 virus infection. In addition to lung infection and viremia, the highly pathogenic H7N9 virus could cause multiple organ infection and injury.

Effect of interleukin-6 (IL-6) on the vascular smooth muscle contraction in abdominal aorta of rats with streptozotocin-induced diabetes.

Patients with type 1 diabetes are at a risk of hypertension. However, the mechanisms behind the findings are not completely known. The aim of the present study was to investigate involvement of interleukin-6 (IL-6) on the contraction of abdominal aorta in rats with type 1 diabetes. IL-6 levels in the plasma of rats with streptozotocin (STZ)-induced diabetes were determined by ELISA. The abdominal aorta was dissected free of fat and connective tissues and then cut into spiral rings. The endothelium-denuded strip was vertically suspended in tissue chambers containing 5 ml Krebs solution at 37 degrees C and bubbled continuously with 95% O2-5% CO2. The effects of phenylephrine (Phe) on the contractile responses of abdominal aorta were recorded. The effects of IL-6 and anti-rat IL-6 antibody on the Phe-induced response were also examined. Plasma levels of IL-6 increased time-dependently in rats with STZ-induced diabetes. Phe caused concentration-dependent contraction in aortic rings. Phe-induced contractions were higher in vascular strips of STZ-induced diabetic rats than that of control rats. Pretreatment of vascular strips with IL-6 for 1 h did not cause contraction but enhanced the contraction in response to Phe. Treatment of the vascular strips with an anti-IL-6 antibody for 1 h decreased the Phe-induced contractions. These results suggest that IL-6 causes vascular smooth muscle contraction in abdominal aorta of rats with type 1 diabetes.

Liver injury in septic mice were suppressed by a camptothecin-bile acid conjugate via inhibiting NF-κB signaling pathway.

BACKGROUND AND OBJECTIVES: Sepsis is a life-threatening organ dysfunction syndrome arising from uncontrolled inflammatory responses. Liver injury is a crucial factor for the prognosis of sepsis. Camptothecins (CPTs) have been reported to suppress the inflammatory response induced by sepsis. G2, a CPT-bile acid conjugate, has been demonstrated the property of liver targeting in our previous research. This study aimed to research the effects of G2 on liver injury induced by cecal ligation and puncture (CLP). METHODS: C57BL/6 mice were subjected to CLP surgery, and effects of G2 on liver damage and survival rates of CLP-induced mice were evaluated. To detect the related markers of hepatic injury or neutrophil infiltration, inflammatory cytokines and protein levels, hematoxylin-eosin staining assay, corresponding Detection Kits assay, ELISA and Western blot analysis were performed. RESULTS: Intraperitoneal administration of G2 reduced liver injury and enhanced the survival rates in mice with sepsis. Treatment with G2 decreased the levels of hepatic injury markers aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in the serum of mice induced by CLP. The hepatic level of neutrophil infiltration marker myeloperoxidase (MPO) was reduced in G2 administration group. And the levels of serum inflammatory cytokines, including Tumor Necrosis Factor-α (TNFα), Interleukin-6 (IL-6) and IL-1ß, were decreased by G2. Furthermore, the results of Western blot analysis indicated that G2 suppressed the up-regulation of NF-κB p-P65 and p-IκBα. It suggested that G2 suppressed the activation of NF-κB signaling pathway. CONCLUSION: G2 alleviated sepsis-induced liver injury via inhibiting the NF-κB signaling pathway.

Synthesis of Oxazolidin-2-ones from Unsaturated Amines with CO2 by Using Homogeneous Catalysis.

Carbon dioxide (CO2 ), a well-known greenhouse gas, is also a nontoxic, readily accessible, and renewable one-carbon (C1) source. However, owing to its thermodynamic stability and kinetic inertness, the efficient utilization of CO2 is challenging. Much effort has been devoted to achieving efficient and selective organic transformations of CO2 . Recently, the synthesis of important oxazolidin-2-ones from unsaturated amines by using CO2 has attracted much attention and been heavily studied. This Focus Review presents recent advances in this area by using homogenous catalysis. The cyclization of amines that contain alkynes, alkenes, and allenes with CO2 is discussed, and possible reaction mechanisms and applications of these transformations are also described.

Active immunization with GnRH-tandem-dimer peptide in young male rats reduces serum reproductive hormone concentrations, testicular development and spermatogenesis.

GnRH sterilization vaccines have been developed for various practical and clinical reasons. However, conjugation of GnRH peptide to carrier protein has many drawbacks, hampering the further commercialization of GnRH vaccines. In this study, a new nonconjugated GnRH vaccine, D-Lys6-GnRH-tandem-dimer peptide (TDK), emulsified in Specol adjuvant was investigated for its immunocastration efficacy in young male rats. Prepubertal male rats were randomly allocated into three groups (n = 12): control (no treatment), surgically castrated or immunized against 100 µg TDK in Specol adjuvant at 6 weeks of age (with a booster 8 weeks later). Blood samples (for antibody titers and hormone concentrations) were collected at 2-week intervals until rats were killed (18 weeks of age). Compared to intact controls, active immunization against TDK reduced (P < 0.05) serum concentrations of testosterone, inhibin B, LH and FSH, prevented the onset of spermatogenesis at puberty. Furthermore, mRNA expressions of GnRH receptor, LH-ß and FSH-ß in the pituitary, LH receptor, FSH receptor, inhibin α, ßA and ßB subunit in the testes were decreased in immunocastrated rats compared to intact controls (P < 0.05). These results demonstrate for the first time that GnRH-tandem-dimer peptide emulsified in Specol is a promising veterinary sterilization medicine.

Oxytocin microinjected into dorsal motor nucleus of the vagus excites gallbladder motility via NMDA receptor-NO-cGMP pathway.

Our recent study indicated that, in the dorsal motor nucleus of the vagus (DMV), the N-methyl-D-aspartic acid (NMDA) receptor-nitric oxide (NO)-cGMP pathway participated in the regulation of gallbladder motility in rabbits. Oxytocin (OT) is involved as a neurotransmitter in autonomic regulation. The aim of the present experiments is to investigate the effect of OT microinjected into DMV on the gallbladder motility and the involvement of NMDA receptor-NO-cGMP pathway. A frog bladder connected with transducer was inserted into the gallbladder to record the gallbladder pressure. Microinjection of OT (10-50 nmol/L, 100 nl) dose dependently increased the strength of gallbladder phasic contraction. The excitatory effect of OT (10 nmol/L, 100 nl) was completely abolished by atosiban (10 mmol/L, 100 nl), the specific OT receptor antagonist, but was not influenced by [deamino-Pen(1), O-Me-Tyr(2),Arg(8)]-vasopressin (10 mmol/L, 100 nl), the V(1) receptor antagonist. Pretreatment of ketamine (10 mmol/L, 100 nl), the NMDA receptor antagonist, suppressed the gallbladder motor response to OT; but pretreatment of 6-Cyaon-7-Nitroquinoxaline-2,3-(1H,4H)-Dione (CNQX; 10 mmol/L, 100 nl), the non-NMDA receptor antagonist, did not affect it. Pretreatment of L-NAME (10 mmol/L, 100 nl), the nitric oxide synthase (NOS) inhibitor, or methyl blue (10 mmol/L, 100 nl), the guanylyl cyclase inhibitor, inhibited the excitatory effect of OT on gallbladder motility. Hence, we deduced that the microinjection of OT into the DMV enhanced the gallbladder motility through binding specific OT receptors and activating the NMDA receptor-NO-cGMP pathway.

[Caspase-3 plays a required role in PC12 cell apoptotic death induced by roscovitine].

Roscovitine is a specific inhibitor of cyclin-dependent kinases (cdks) cdc2/cyclin B, cdk2/cyclin A, cdk2/cyclin E and cdk5/p35. The studies on the enzyme inhibitory properties and cellular effects of roscovitine revealed that it arrests cells in G(2)/M and G(1)/S phase, inhibits the proliferation of mammalian cells and induces cell death. However, the characteristics of cell death and exact mechanism by which this cdk inhibitor kills transformed cells are unknown. We previously investigated that the roscovitine induces apoptotic death of mitotic PC12 cells. The present study was to identify whether the roscovitine-induced death is related with the specific elements of caspases in pathway of apoptosis. The morphological data of caspase-3 immunofluorocytochemistry double staining with hoechst 33342 indicated that apoptotic nuclei were identified as nuclei with chromatin condensation and nuclear fragmentation, and that caspase-3 active p17 subunit co-existed in PC12 cells treated with roscovitine 50 micromol/L for 4 h. The number of the caspase-3 positive cells increased significantly to about 42%, as compared with the normal control (P<0.001). The data of MTT assay showed that the number of viable cells treated by roscovitine (50 micromol/L) alone for 12 h was 29.03%, of the untreated controls. Both a broad-spectrum caspase inhibitor Z-VAD-FMK (50 mumol/L) and a specific caspase-3 inhibitor Z-DEVD-FMK (100 micromol/L) increased viable PC12 cells to 45.16%, (Z-DEVD-FMK) and 58.06%, (Z-VAD-FMK), respectively, in the presence of roscovitine. Non-erythroid a-spectrin is a cytoskeleted protein that is a substrate of caspase-3 cysteine proteases. To confirm the activity of caspase-3 that produced in roscovitine (50 micromol/L for 12 h)-induced PC12 cell death, activated caspase-3 specific 120 kDa spectrin breakdown products (SBDP) were detected by Western bloting using the mouse anti-non-erythroid a-spectrin monoclonal antibody. The mean relative density of bands corresponding to caspase-3 specific SBDP levels were significantly increased in the cytosolic fractions treated with roscovitine, as compared to the normal control (P<0.001). These results indicate that caspase signals, especially caspase-3 signal are necessary for the progression of proliferating PC12 cell apoptotic death evoked by roscovintine.

[A study on the effect of biomineralization and phosphorylation performed on the titanium implant surfaces].

OBJECTIVE: To suggest a chemical surface treatment for titanium and to initiate the formation of hydroxycarbonated apatite (HCA) on titanium surface during in vitro bioactivity tests in simulated body fluid (SBF). METHODS: To improve the bone-bonding ability of Ti implants, commercially pure titanium (cpTi) by a simple chemical pre-treatment in orthophosphoric acid (H(3)PO(4)) with different density was activated, and then the phosphorylation specimens were soaked in SBF to investigate the function of biomineralization. RESULTS: The scanning electron microscope (SEM) photographs showed that the surfaces of the pre-treated samples were characterized by a complex construction, which consisted of a mesh-like morphology matrix (a micro-roughened surface) and an uniform surface with different morphous of titanium dihydrogen orthophosphate [Ti(H(2)PO(4))(3)] crystal. After 14 days in SBF a homogeneous biomimetic apatite layer precipitated. CONCLUSIONS: These data suggest that the treatment of titanium by acid etching in orthophosphoric acid is a suitable method to provide the titanium implant with bone-bonding ability.