[Research progress on the correlation between changes in gut microbiota and sarcopenia in patients with cirrhosis]

Sarcopenia is one of the common complications of cirrhosis. Studies have demonstrated that patients with cirrhosis combined with sarcopenia have a high mortality rate. The occurrence of sarcopenia may be associated with inflammatory states and metabolic abnormalities caused by changes in the gut microbiota environment, but such studies are currently relatively lacking. This article elaborates on the correlation between changes in the gut microbiota environment, as well as the diagnosis and treatment, in order to provide reference and assistance for the treatment of patients with cirrhosis and sarcopenia.

Bu-Yin-Qian-Zheng Formula Ameliorates MPP+-Induced Mitochondrial Dysfunction in Parkinson's Disease via Parkin

As a typical traditional Chinese medicine, Bu-Yin-Qian-Zheng Formula (BYQZF) has been shown to have neuroprotective effects in patients with Parkinson’s disease (PD), particularly by ameliorating mitochondrial dysfunction and regulating expression of the parkin protein. However, the underlying mechanisms by which BYQZF affects mitochondrial function through parkin are unclear. Accordingly, in this study, we evaluated the mechanisms by which BYQZF ameliorates mitochondrial dysfunction through parkin in PD. We constructed a parkin-knockdown cell model and performed fluorescence microscopy to observe transfected SH-SY5Y cells. Quantitative real-time reverse transcription polymerase chain reaction and western blotting were conducted to detect the mRNA and protein expression levels of parkin. Additionally, we evaluated the cell survival rates, ATP levels, mitochondrial membrane potential (ΔΨm), mitochondrial morphology, parkin protein expression, PINK1 protein expression, and mitochondrial fusion and fission protein expression after treatment with MPP⁺ and BYQZF. Our results showed that cell survival rates, ATP levels, ΔΨm, mitochondrial morphology, parkin protein levels, PINK1 protein levels, and mitochondrial fusion protein levels were reduced after MPP⁺ treatment. In contrast, mitochondrial fission protein levels were increased after MPP⁺ treatment. Moreover, after transient transfection with a negative control plasmid, the above indices were significantly increased by BYQZF. However, there were no obvious differences in these indices after transient transfection with a parkin-knockdown plasmid. Our findings suggest that BYQZF has protective effects on mitochondrial function in MPP⁺-induced SH-SY5Y cells via parkin-dependent regulation of mitochondrial dynamics.

[Serum status and their changes of some vitamin substances and homocysteine in healthy subjects in Beijing]

Objective: To investigate serum status of folate, vitamin B(12), homocysteine (Hcy) and hydroxyvitamin D (25OHD) and their trends in different gender and age groups. Methods: This was a cross-sectional study. The enrolled subjects were those received medical examination in Beijing Hospital from September to November 2018 and were identified as appeared healthy persons. 1220 subjects were recruited and were divided into groups of young and middle age group (30-49 years, 50-59 years) and the elderly group (60-69 years, 70-79 years and ≥80 years). We measured folate, vitamin B(12), and 25OHD using electrochemiluminescence by chemiluminescence immunoassay. Hcy was measured by autobiochemical analyzer. Results: Total folate levels in male and female subjects were 7.16 (4.74-10.75) and 9.17 (6.49-13.55) μg/L respectively. Total vitamin B(12) levels in the male and female were 505.60 (386.80-700.90) and 582.60 (430.70-846.98) ng/L respectively. Hcy levels were 14.68 (12.25-18.58) and 11.29 (9.65-13.58) μmol/L. 25OHD levels were 21.60 (16.40-28.70) and 16.80 (12.30-24.15) μg/L respectively. Total folate and vitamin B(12) levels in female were higher than that in male subjects (Z=-7.796, -4.772, P<0.001). However, total Hcy and 25OHD levels in male were higher than that in female subjects (Z=-15.230, -8.447, P<0.001). Comparing with the substances in the above age groups, folate level in the elderly was lower than that in the younger age and middle age groups.However, vitamin B(12), 25OHD and Hcy levels were higher in the elderly groups. Furthermore, the levels of folate, vitamin B(12) and 25OHD were getting higher in the group of ≥80 years female compared with the rest of the age groups, but it turned lower in the male group of ≥80 years. Conclusions: There are some differences in the serum values of folate, vitamin B(12), Hcy and 25OHD among various age groups as well as between males and females. These should be considered in the development of national reference ranges.

Contribution to the knowledge of the genus Cucujus Fabricius (Coleoptera, Cucujidae) from China

Cucujus costatus Zhao Zhang, new species is described from Guangdong, China. This new species can be easily recognized by the longitudinal elevated carinae on elytra and its strongly convex eyes. Additional records for C. kempi Grouvelle, 1913 and C. elongatus Lee Pütz, 2008 are added. A key to the known Chinese species of Cucujus Fabricius is given.

[Mosquitoes, midges and related arboviruses in southeast Sichuan province]

Objective: To investigate the distribution patterns of mosquitoes, midges and related arboviruses in Sichuan province. Methods: Blood-sucking insects were collected from houses and pens, using the ultraviolet lights. Mosquito samples were classified according to morphologic characteristics and then stored at liquid nitrogen. All samples were incubated with BHK-21 and C6/36 cells for virus isolation and then detected for their viral genes. Sequences of the virus were identified and analyzed by molecular biological software, such as BioEdit 7.0.5.3, MEGA 6.0. Results: In total, 17 019 mosquitoes from 3 genera and 4 species and 12 700 midges were collected from the southeast regions of Sichuan province in 2016 and 2017. Among them, 79.4% (13 519/17 019) belonged to Culex tritaeniorhynchus with 11.1% (1 897/17 019) as Armigeres subalbatus, 5.5% (930/17 019) were Anopheles sinensis and 4.0% (673/17 019) were Anopheles sinensis 3 virus strains that isolated from Culex tritaeniorhynchus were identified as typeⅠ Japanese encephalitis virus. Seven pools of mosquitoes isolated from Hejiang county were identified Japanese encephalitis virus gene positive through PCR amplification. With 4 pool midges were detected positive for Akabane virus through PCR gene amplification while midges samples didn't have virus isolates. Conclusions: Culex tritaeniorhynchus appeared the predominant species in the southeast regions of Sichuan. Japanese encephalitis virus transmitted by mosquitoes and Akabane virus by midges were prevalent in southeast Sichuan province.

[The efficacy of ultrasound-guided spinal nerve posterior ramus pulsed radiofrequency treatment for aged lower back post-herpetic neuralgia]

Objective: To evaluate the efficacy of ultrasound-guided spinal nerve posterior ramus pulsed radiofrequency treatment of lower back post-herpetic neuralgia. Methods: One hundred and twenty-eight cases of lower back or anterior abdominal wall acute post-herpetic neuralgia patients were enrolled. They were randomly divided into two groups. Group A: oral treatment only with gabapentin+ celecoxib+ amitriptyline. Group B: while taking these drugs, patients were treated with radiofrequency pulses using a portable ultrasound device and the paravertebral puncture technique.In both groups, sudden outbreaks of pain were treated with immediate release 10 mg morphine tablets. Before and one week, two weeks, four weeks, eight weeks after treatment, visual analogue scale (VAS) was used for pain score, Pittsburgh sleep quality index scale (PSQI) was used to evaluate sleep quality, and morphine consumption was recorded. Eight weeks after treatment analgesic efficacy was evaluated. Treatment efficiency and significant efficiency was calculated while the occurrence of complications were documented. Results: In the control group, the VAS of T_1,T_2,T₃ and T₄ were 6.7 ±1.2, 5.2 ± 1.0, 3.3 ±1.1, 3.0±0.9.However, at the same time points, the VAS in the treatment group were 3.1±1.0, 2.2±0.7, 1.4±0.5, 1.2±0.5, respectively.The radio frequency group decreased significantly compared with the control group, the difference was statistically significant (t=17.925, 19.662, 12.580, 13.987, all P<0.05). Four weeks after treatment, the TNF-α in the control group was (11.04±2.36)ng/L, and the TNF-β in the radio frequency group was (8.07±2.13) ng/L. After the treatment, the TNF-α of the radio frequency group was lower than the control group, and the difference was statistically significant (t=-6.267, P<0.05). The IL-1β in the control group was (3.47±1.09) ng/L after treatment.The IL-1β in the radio frequency group was (1.96 ±0.56) ng/L, the IL-1β in the radio frequency group was lower than the control group and the difference was statistically significant (t=-8.266, P<0.05). Pearson correlation analysis showed that before and after the treatment of TNF-α were positively correlated with VAS score (r=0.455, 0.327, all P<0.05). IL-1β before and after treatment were positively correlated with VAS score (r=0.369, 0.357, all P<0.05). At T_1,T_2,T₃ and T₄, PSQI in the control group were 8.5±1.5, 7.3±1.4, 6.2±1.3 and 6.0±0.9 respectively.PSQI in the radio frequency group at the same time points were 6.5±1.4, 5.1±1.2, 4.0±1.1 and 3.9±0.5.Comparison between the two groups after treatment, radio frequency group was lower than the control group significantly, and the difference was statistically significant (t=7.798, 9.545, 10.335, 16.318, all P<0.05). Morphine consumption of the control group at T_1,T_2,T_3,T₄ were (22.5±2.2), (15.5±2.9), (6.8±1.5) and (4.2±0.9)mg.However, morphine consumption of the radio frequency group were (13.2±2.5), (7.2±2.7), (3.2±0.6) and (2.2±0.5)mg.Comparison between the two groups after treatment, morphine consumption of the radio frequency group decreased significantly than the control group, and the difference was statistically significant (t=22.341, 16.758, 17.827, 15.541, all P<0.05). During the operation , no error occurred with needle penetrating the abdominal cavity, chest, offal or blood vessels. Conclusion: Ultrasound-guided spinal nerve posterior ramus pulsed radio frequency treatment of lower back or anterior abdominal wall post-herpetic neuralgia proves effective and can reduce patient morphine usage and lead to fewer adverse reactions.

Characterization of submicron particles during biomass burning and coal combustion periods in Beijing, China

An Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) was deployed along with other observation instruments to measure the characteristics of PM1 (particulate matter with a vacuum aerodynamic diameter of ≤1μm) during the biomass burning period (October 1 to 27; BBP) and the coal combustion period (December 10 to 31; CCP) in Beijing in 2014. The average PM1 mass concentrations during the BBP and CCP were 82.3 and 37.5μgm(-3), respectively. Nitrate, ammonium and other pollutants emitted by the burning processes, especially coal combustion, increased significantly in association with increased pollution levels. Positive matrix factorization (PMF) was applied to a unified high-resolution mass spectra database of organic species with NO(+) and NO2(+) ions to discover the relationships between organic and inorganic species. One inorganic factor was identified in both periods, and another five and four distinct organic factors were identified in the BBP and CCP, respectively. Secondary organic aerosols (SOAs) accounted for 55% of the total organic aerosols (OAs) during the BBP, which is higher than the proportion during the CCP (oxygenated OA, 40%). The organic nitrate and inorganic nitrate were first successfully separated through the PMF analysis based on the HR-ToF-AMS observations in Beijing, and organic nitrate components accounted for 21% and 18% of the total nitrate mass during the BBP and CCP, respectively. Although the PM1 mass concentration during the CCP was much lower than in the BBP, the average concentration of polycyclic aromatic hydrocarbons (PAHs) during the CCP (107.3±171.6ngm(-3)) was ~5 times higher than that in the BBP (21.9±21.7ngm(-3)).

A polymorphism within ErbB4 is associated with risk for hepatocellular carcinoma in Chinese population

AIM: To investigate the association between hepatocellular carcinoma (HCC) susceptibility and a 12-bp insertion/deletion polymorphism (rs6147150) in the 3’UTR of ErbB4.

METHODS: Using a case-control design, the rs6147150 genotypes in 270 patients with HCC and 270 healthy controls were determined by direct polymerase chain reaction and polyacrylamide gel electrophoresis. Logistic regression was used to analyze the association between the polymorphism and cancer risk.

RESULTS: Computational modeling suggested that rs6147150 was located in the seed region of hsa-let-7c, a potential target sequence in ErbB4 3’UTR. Logistic regression analysis showed that, compared with individuals homozygous for wild-type, heterozygotes [adjusted odds ratio (OR) = 1.48, 95% confidence interval (CI) = 1.03-2.17, P = 0.034] and individuals homozygous for 12-bp del/del (OR = 2.50, 95% CI = 1.37-4.56, P = 0.001) were at significantly higher risk of HCC. Carriers of the “del” allele of rs6147150 had a 1.59-fold increased risk for HCC (95% CI = 1.22-2.07, P = 0.003).

CONCLUSION: rs6147150 may be associated with HCC risk, in part through let-7c-mediated regulation, and may be involved in the pathogenesis of HCC in Chinese populations.

In vitro antigen-specific cytotoxic T cell response against esophageal carcinoma cells induced by HPV18E7-transfected dendritic cells

Human Papillomavirus (HPV)-associated esophageal carcinoma (EC) is a high incidence tumor worldwide. Dendritic cell (DC)-based tumor vaccine is considered an alternative therapy to treat EC. Here we developed a DC-based vaccine by transfecting cord blood CD34+ stem cell-derived DC with HPV18E7 gene, observed its biological characteristics and the antigen-specific T-cell cytotoxicity on EC cells induced by HPV18E7-DC in vitro. Our results showed that 1) HPV18E7 gene transfer did not change the typical morphology of mature DC, 2) the representative phenotypes of mature DC (CD80, CD86, and CD83) were highly expressed in HPV18E7- DC (81.6%, 80.5%, and 86.6%, respectively), 3) the expression level of 18E7 protein in HPV18E7-DC was 47.5%, and 4) the specific cytotoxicity against EC cells was significantly higher than that in controls (p<0.01). This study indicates the possibility of a DC-based immunotherapy in HPV-associated EC.

Microencapsulated human hair dermal papilla cells: a substitute for dermal papilla?

Dermal papillae (DP) play a pivotal role in hair formation, growth and cycling. However, the number of DP is limited. In this study, we report the production of "reconstructed DP" by enclosing DP cells within an alginate-polylysine-alginate (APA) semipermeable membrane. MTT assay and electron microscopy showed that the microencapsulated dermal papilla cells retained normal activity. The microcapsules were implanted into rat footpads, which lack follicles and sebaceous glands, to assess their inductive properties. Histologic examination showed that numbers of follicle and sebaceous gland structures formed in the footpads within 6-10-week period. At the 10 weeks following transplantation, hair fibers were visible in the footpad. These findings indicate that the DP cell microcapsules retain the capacity to initiate follicle regeneration and could be considered a substitute for fresh isolated DPs.

LHRH-PE40-Induced Vascular Leak Syndrome

AIM

This study was designed to study the toxicity of LHRH-PE40, a recombinant DNA-derived protein composed of the decapeptide known as luteinizing hormone-releasing hormone and the translocation and catalytic domains of pseudomonas exotoxin A.

METHOD

Single-dose and repeat-dose toxicity of intravenous injection of LHRH-PE40 was studied by clinical signs, hematology, blood chemistry and histopathology, and lung permeability to Evans blue dye. Additional study was performed to find the relationship between dexamethasone pretreatment and vascular leak syndromes.

RESULTS

Dyspnea, increased hemocrit, low serum total protein, lung edema, and high lung permeability were found on rats treated with single or repeated doses of LHRH-PE40. Dexamethasone pretreatment before LHRH-PE40 administration partly lowered morbidity of rats.

CONCLUSION

LHRH-PE40-induced vascular leak syndrome was the chief cause of rats' death. Dexamethasone pretreatment partly reduced the frequency of vascular leak syndrome. Hypotheses about vascular leak syndromes were also formed by reviewing recent literature.

Effects of dendritic cells from cord blood CD34+ cells on human hepatocarcinoma cell line BEL-7402 in vitro and in SCID mice

AIM: To develop a cancer vaccine of dendritic cells derived from human cord blood CD34+ cells and to investigate its cytotoxicity on human hepatocarcinoma cells in vitro and in sever combined immunodeficiency (SCID) mice.

METHODS: Lymphocytes from cord blood or peripheral blood were primed by DCs, which were derived from cord blood and pulsed with whole tumor cell lysates. Nonradiative neutral red uptake assay was adopted to detect the cytotoxicity of primed lymphocytes on human hepatocarcinoma cell line BEL-7402 in vitro. The anti-tumor effect of primed lymphocytes in vivo was detected in SCID mice, including therapeutic effect and vaccination effect.

RESULTS: The cytotoxicity of DC vaccine primed lymphocytes from cord blood or peripheral blood on human hepatoc-arcinoma cell line BEL-7402 was significantly higher than that of unprimed lymphocytes in vitro (44.09% vs 14.69%, 47.92% vs 19.44%, P<0.01). There was no significant difference between the cytotoxicity of primed lymphocytes from cord blood and peripheral blood (P>0.05). The tumor growth rate and tumor size were smaller in SCID mice treated or vaccinated with primed lymphocytes than those with unprimed lymphocytes. SCID mice vaccinated with primed lymphocytes had a lower tumor incidence (80% vs 100%, P<0.05) and delayed tumor latent period compared with mice vaccinated with unprimed lymphocytes (11 d vs 7 d, P<0.01).

CONCLUSION: Vaccine of cord blood derived-DCs has an inhibitory activity on growth of human hepatocarcinoma cells in vitro and in SCID mice. The results also implicate the potential role of cord blood derived-DC vaccine in clinical tumor immunotherapy.

Study on immune function of dendritic cells in patients with esophageal carcinoma

AIM: To investigate the immune function of dendritic cells from both peripheral blood and operated tissues of esophageal carcinoma patients in order to find the relationship between the immune function of dendritic cells and the pathogenesis of esophageal carcinoma.

METHODS: The expression of CD83, CD80, and CD86 on the surface of dendritic cells cultured from the peripheral blood of patients was detected compared with that from health donors using flow cytometry. The ability of dendritic cells to induce T lymphocyte proliferation was evaluated by a liquid scintillation counter. The expression of CD80, CD86, CD83, and S-100 proteins was assessed in esophageal carcinoma tissues using immunohistochemical method.

RESULTS: Compared with those from healthy donors, dendirtic cells cultured from the peripheral blood of patients expressed lower CD80 and CD86. Furthermore, the ability of dendritic cells in patients to induce T lymphocyte proliferation was significantly lower than that of the control group. Compared with the control group, the positive expression ratio and frequencies of CD80, CD86, and S-100 in esophageal carcinoma tissues were significantly down regulated. The expression of CD83 was up-regulated in the pericancerous tissues, but no expression was found in the cancerous nodules.

CONCLUSION: The impaired immune function and the decreased number of dendritic cells cause pathogenesis and progression of esophageal carcinoma.

A vaccine prepared by fusion of H22 cells with the spleen-drived dendritic cells

AIM: To prepare a cancer vaccine (H₂₂-DC) based on fusion of hepatocarcinoma cells (H₂₂) with dendritic cells (DC) of mice and to analyze the biological characteristics, tumorigenicity and specific CTL activity of H₂₂-DC.

METHODS: DCs were fused with H₂₂ cells and fusion cells were marked with CD11c MicroBeads. The teachniques of cell culture, immunocytochemistry and light microscopy were used to test the characteristics of growth morphology of H₂₂-DC in vitro. As an immunogen, H₂₂-DC was inoculated subcutaneously into the right armpit of Balb/C mice, and their tumorigenicity in vivo was observed. MTT was used to test the CTL activity of murine spleen in vitro.

RESULTS: H₂₂-DC was able to divide and prolifterate in vitro,but its activity of proliferation was significantly decreased as compared with H₂₂ cells and its growth curve was flatter than that of H₂₂ cells. The spleen CTL activity against H₂₂ cells in mice implanted with fresh H₂₂-DC was significantly higher than that in control groups (P < 0.01).

CONCLUSION: H₂₂-DC can significantly stimulate the specific CTL activity of murine spleen. The DC vaccine is likely to become a helpful approach in immunotherapy of hepatocellular carcinoma.

Antitumor immunopreventive and immunotherapeutic effect in mice induced by hybrid vaccine of dendritic cells and hepatocarcinoma in vivo

AIM: To develop atumor vaccine by fusion of H22 hepatocarcinoma cells and DC, and to study its protective and therapeutical effect against H22 cell.

METHODS: H22-DC vaccine was produced by PEG fusion of H22 and DC induced by cytokine released from splenic mononuclear cells, sorted by CD11c magnetic microbead marker. It was injected through the tail vein of the mice and the H₂₂-DC oncogenesis was detected in the liver, spleen and lung. In order to study the therapeutical and protective effect of H₂₂-DC against tumor H₂₂, two groups were divided: immune group and therapeutic group. Immune group was further divided into P, D, HD and H subgroups, immunized by PBS, DC, H₂₂-DC and inactivated H₂₂, respectively, and attacked by H₂₂ cell. The tumor size, tumor weight, mice survival time and tumor latent period were recorded and statistically analyzed; Therapeutical group was divided into three subgroups of P, D and HD, and attacked by H₂₂, then treated with PBS, DC, and H₂₂-DC, respectively. Pathology and flow cytometry were also applied to study the mechanism how the H₂₂-DC vaccine attacked on the H₂₂ cell.

RESULTS: 1. No oncogenesis was found in spleen, lung and liver after H22-DC injection. 2. Hybrid vaccine immunized mice had strongest CTL activity. 3. In the immune group, latent period was longer in HD subgroup than that in P, H and D subgroup; and tumor size and weight were smaller in HD subgroup than that in P, H and D subgroup. 4. In therapeutic group, tumor size was smaller in HD subgroup than that in P, D subgroup.

CONCLUSION: 1. H22-DC tumor vaccine is safe without oncogenesis in vivo. 2. Hybrid vaccine can stimulate potent specific CTL activity against H22. 3. H22-DC vaccine has distinctive prophylatic effect on tumor H22 and can inhibit the tumor growth.

Antitumor activities of human dendritic cells derived from peripheral and cord blood

AIM: To observe the biological specialization of human peripheral blood dendritic cells (DC) and cord blood derived DC and its effects on effector cells killing human hepatocarcinoma cell line BEL-7402 in vitro.

METHODS: The DC biological characteristics were detected with immunohistochemical and MTT assay. Two antitumor experimental groups are: peripheral blood DC and cord blood DC groups. Peripheral blood DC groups used LAK cells as the effector cells and BEL-7402 as target cells, while cord blood DC groups used CTL induced by tumor antigen twice pulsed DC as effector cells and BEL-7402 as target cells, additional peripheral blood DC and cord blood DC are added to observe its stimulating activities to effector cells. The effector¡äs cytotoxicity to tumor cells were detected with neutral red colorimetric assay at two effector/ target ratios of 5:1 and 10:1.

RESULTS: Peripheral blood DC and cord blood DC highly expressed HLA-ABC, HLA-DR, HLA-DQ, CD54 and S-100 protein. The stimulating activities to lymphocyte proliferation were compared between experimental groups (DC added) and control group (no DC added), in six experiment subgroups,the DC/lymphocyte ratio was sequentially 0.25:100, 0.5:100, 1:100, 2:100, 4:100 and 8:100, A values(^-x±s) were 0.75396 ± 0.009, 0.84916 ± 0.010, 0.90894 ± 0.012, 0.98371 ± 0.007, 1.01299 ± 0.006 and 1.20384 ± 0.006 in peripheral blood DC groups and 0.77650 ± 0.005, 0.83008 ± 0.007, 0. 92725 ± 0.007, 1.05990 ± 0.010, 1.15583 ± 0.011, 1. 22983 ± 0.011 in cord blood DC groups. A value was 0.59517 ± 0.005 in control group. The stimulating activities were higher in experimental groups than in control group (P < 0.01), which were increased when the DC concentration was enlarged (P < 0.01). Two differently derived DCs had the same phenotypes and similar stimulating activities (P > 0.05). In peripheral blood DC groups, the cytotoxicity (^-x±s) of the LD groups (experimental groups) and L groups (control group) was 58.16% ± 2.03% (5:1), 46c18% ± 2.25% (10:1) and 38c13% ± 1.29% (5:1) and 65.40% ± 1.56% (10:1) respectively; in cord blood DC groups, TD groups (experimental groups) and T groups (control groups) were 69.71% ± 2.33% (5:1), 77.64% ± 1.94% (10:1) and 56.89% ± 1.82% (5:1) and 60.99% ± 1.42% (10:1) respectively. The cytotoxicity activities were enhanced with increased effector/target ratio (P < 0.01). At the same effector/target ratio, the cytotoxicity of experimental groups were bigger than that of control groups (P < 0.01). The cytotoxicity activities of cord blood DC groups were higher than that of peripheral blood DC groups (P < 0.01).

CONCLUSION: Peripheral blood DC and cord blood DC are mature DC in morphology and function, both can enhance the effector cell killing activities to hepatocarcinoma cells. DC pulsed with tumor antigen can induce higher specific CTL activity than unpulsed DC.

Human papillomavirus 16 E6 is associated with the nuclear matrix of esophageal carcinoma cells

AIM: To explore the etiologic role of HPV infection in esophageal carcinoma, and the association of HPV-16 E6 with the nuclear matrix of carcinoma cells.

METHODS: Two esophageal carcinoma cell lines, EC/CUHK1 and EC/CUHK2, were tested for HPV-16 E6 subgenetic fragment by polymer a se chain reaction amplification of virus DNA associated nuclear matrix. RT-PCR and immunocytochemistry were also used to visualize the expression of E6 subgene in the cells.

RESULTS: The HPV-16 E6 subgenetic fragment was found to be present in nuclear matrix-associated DNA, E6 oncoprotein localized in the nucleus where it is tightly associated with nuclear matrix after sequential extraction in EC/CUHK2 cells. It was not detected, however, in EC/CUHK1 cells.

CONCLUSION: The interaction between HPV-16 E6 and nuclear matrix may contribute to the virus induced carcinogenesis in esophageal carcinoma.

Effect of bilateral testicular resection on thymocyte and its microenvironment in aged mice

AIM

To observe the changes in thymocyte and its microenvironment in aged mice after bilateral testicular resection.

METHODS

In male old mice, at the 25th day after testicular resection, the peripheral blood and thymus were collected. Blood and thymus suspension smears were prepared for quantitative histochemistry and immunohistochemistry study under light and electron microscopes.

RESULTS

In testes resected mice the size and the weight of thymus were markedly increased. The demarcation between cortex and medulla was clear. The cortex was thickened and the cell density was increased. The ratio of cortex/medulla stereometry was increased. The total cell count, thymocyte count, the percentage of acid alpha-naphthyl acetate esterase (ANAE) positive thymocytes, nonlymphocytes and the rosette formation of macrophages and thymocytes were all increased. The thymocytes surrounded closely to the light thymic epithelial cells, dendritic cells or macrophages. The lymphocytes, particularly the ANAE positive lymphocytes of peripheral blood were increased.

CONCLUSION

After bilateral testicular resection, the thymus of aged male mice showed morphological regeneration and the thymocytes and its microenvironment appeared to be definitely improved. It is suggested that testicular resection may improve immune function.

Effect of a cancer vaccine prepared by fusions of hepatocarcinoma cells with dendritic cells

AIM: To prepare a cancer vaccine (H₂₂-DC) expressing high levels of costimulatory molecules based on fusions of hepatocarcinoma cells (H₂₂) with dendritic cells (DC) of mice and to analyze the biological characteristics and induction of specific CTL activity of H₂₂-DC.

METHODS: DCs were isolated from murine spleen by metrizamide density gradient centrifugation, purified based on its characteristics of semi-adhesion to culture plates and FcR^-, and were cultured in the medium containing GM-CSF and IL-4. A large number of DC were harvested. DCs were then fused with H₂₂ cells by PEG and the fusion cells were marked with CD11c MicroBeads. The H₂₂-DC was sorted with Mimi MACS sorter. The techniques of cell culture, immunocytochemistry and light microscopy were also used to test the characteristics of growth and morphology of H₂₂-DC in vitro. As the immunogen, H₂₂-DC was inoculated subcutaneously into the right armpit of BALB/C mice, and their tumorigenicity in vivo was observed. MTT was used to test the CTL activity of murine spleen in vitro.

RESULTS: DC cells isolated and generated were CD11c+ cells with irregular shape, and highly expressed CD80, CD86 and CD54 molecules. H₂₂ cells were CD11c^- cells with spherical shape and bigger volume, and did not express CD80, CD86 and CD54 molecules. H₂₂-DC was CD11c⁺ cells with bigger volume, being spherical, flat or irregular in shape, and highly expressed CD80, CD86 and CD54 molecules, too. H₂₂-DC was able to divide and proliferate in vitro, but its activity of proliferation was significantly decreased as compared with H₂₂ cells and its growth curve was flatter than H₂₂ cells. After subcutaneous inoculation over 60 d, H₂₂-DC showed no tumorigenecity in mice, which was significantly different from control groups (P < 0.01). The spleen CTL activity against H₂₂ cells in mice implanted with fresh H₂₂-DC was significantly higher than control groups (P < 0.01).

CONCLUSION: H₂₂-DC could significantly stimulate the specific CTL activity of murine spleen, which suggests that the fusion cells have already obtained the function of antigen presenting of parental DC and could present H₂₂ specific antigen which has not been identified yet, and H₂₂-DC could induce antitumor immune response; although simply mixed H₂₂ cells with DC could stimulate the specific CTL activity which could inhibit the growth of tumor in some degree, it could not prevent the generation of tumor. It shows that the DC vaccine is likely to become a helpful approach in immunotherapy of hepatocarcinoma.

Prenatal alcohol exposure retards the migration and development of serotonin neurons in fetal C57BL mice

Incomplete neural tube fusion (iNTF), induced by alcohol, in midline floor and roof plates was found in our recent study. In this study, serotonin (5-HT) neurons, known to be born entirely in the midline raphe at brainstem, were examined during their development with fetal alcohol exposure. Weight-matched C57BL mice pregnant dams were divided into three groups on E8: one received ethanol via a chocolate Sustacal liquid diet providing 20% ethanol-derived calories as the sole source of nutrients (ALC); the second received an isocaloric Sustacal liquid diet and was pair-fed to individual dams in the ethanol-fed group (PF); the third was fed ad lib rat chow (Chow). Fetal brains were obtained on E15 and were processed for immunostaining of 5-HT and its trophic factor, S100 beta. The ascending 5-HT neurons, in normal development, appear bilaterally near midline on E12, and by E15, as seen in chow and PF groups, migrate from the midline germinal zone laterally and dorsally to their final position with rich fibers. In contrast, in the E15 ALC group, many 5-HT-im neurons were found remaining in the midline germinal region or had migrated, but with under-differentiated, sparse fibers. There were 20--30% fewer 5-HT-im neurons in ALC as compared to PF and Chow. In addition, the number of S100 beta cells was less in ALC as compared with PF and Chow groups. No difference was found between PF and Chow in number of 5-HT-im or S100 beta-im cells. The 5-HT neurons found compromised in migration and differentiation may, in part, stem from failure of access to floor plate or midline tissue induction and the insufficient support by S100 beta. As 5-HT neurons have been implicated for signaling brain maturation, fewer 5-HT neurons may have lasting effects on the development of brain or, if persistent in the adult, profoundly affect adult brain function.

In vivo transposon mutagenesis of the methanogenic archaeon Methanosarcina acetivorans C2A using a modified version of the insect mariner-family transposable element Himar1

We present here a method for in vivo transposon mutagenesis of a methanogenic archaeon, Methanosarcina acetivorans C2A, which because of its independence from host-specific factors may have broad application among many microorganisms. Because there are no known Methanosarcina transposons we modified the mariner transposable element Himar1, originally found in the insect Hematobia irritans, to allow its use in this organism. This element was chosen because, like other mariner elements, its transposition is independent of host factors, requiring only its cognate transposase. Modified mini-Himar1 elements were constructed that carry selectable markers that are functional in Methanosarcina species and that express the Himar1 transposase from known Methanosarcina promoters. These mini-mariner elements transpose at high frequency in M. acetivorans to random sites in the genome. The presence of an Escherichia coli selectable marker and plasmid origin of replication within the mini-mariner elements allows facile cloning of these transposon insertions to identify the mutated gene. In preliminary experiments, we have isolated numerous mini-mariner-induced M. acetivorans mutants, including ones with insertions that confer resistance to toxic analogs and in genes that encode proteins involved in heat shock, nitrogen fixation, and cell-wall structures.

Generation of dominant selectable markers for resistance to pseudomonic acid by cloning and mutagenesis of the ileS gene from the archaeon Methanosarcina barkeri fusaro

Currently, only one selectable marker is available for genetic studies in the archaeal genus Methanosarcina. Here we report the generation of selectable markers that encode resistance to pseudomonic acid (PA(r)) in Methanosarcina species by mutagenesis of the isoleucyl-tRNA synthetase gene (ileS) from Methanosarcina barkeri Fusaro. The M. barkeri ileS gene was obtained by screening of a genomic library for hybridization to a PCR fragment. The complete 3,787-bp DNA sequence surrounding and including the ileS gene was determined. As expected, M. barkeri IleS is phylogenetically related to other archaeal IleS proteins. The ileS gene was cloned into a Methanosarcina-Escherichia coli shuttle vector and mutagenized with hydroxylamine. Nine independent PA(r) clones were isolated after transformation of Methanosarcina acetivorans C2A with the mutagenized plasmids. Seven of these clones carry multiple changes from the wild-type sequence. Most mutations that confer PA(r) were shown to alter amino acid residues near the KMSKS consensus sequence of class I aminoacyl-tRNA synthetases. One particular mutation (G594E) was present in all but one of the PA(r) clones. The MIC of pseudomonic acid for M. acetivorans transformed with a plasmid carrying this single mutation is 70 microgram/ml of medium (for the wild type, the MIC is 12 microgram/ml). The highest MICs (560 microgram/ml) were observed with two triple mutants, A440V/A482T/G594E and A440V/G593D/G594E. Plasmid shuttle vectors and insertion cassettes that encode PA(r) based on the mutant ileS alleles are described. Finally, the implications of the specific mutations we isolated with respect to binding of pseudomonic acid by IleS are discussed.

Expression of serotonin transporter protein in developing rat brain

Serotonin transporter (5-HTT), a transmembrane protein, has been shown in adult brain to be distributed not only on synaptic terminals but to a great extent on axons as well. Here we report the ontogeny of 5-HTT and its relationship with serotonin (5-HT) neurons using established 5-HTT and 5-HT antibodies. Both 5-HTT- and 5-HT-immunostaining (-im) appear in 5-HT neurons at embryonic day 12 (E12) in rostral raphe nuclei (RRN). Soon after appearing, 5-HTT-im is highly expressed on axons, similar to adult expression. However, in contrast to adult, 5-HTT-im also outlines the soma-dendrites. Rich 5-HTT-im appears along the entire length of projecting axons, extending to the growth tip. In the next 2 days, intensive 5-HTT-im axons from RRN travel a course preferentially in the floor plate and later, the medial forebrain bundle trajectory. A group of new 5-HT-im neurons and 5-HTT-im axons appear at E13 in caudal raphe nuclei. At E16-18, taking the exact trajectory course of 5-HT axons, 5-HTT-im axons reach ganglionic eminence, olfactory bulb, and cortex and disperse into many brain regions in E18-20. No 5-HTT-im cell bodies were seen in nigral, locus ceruleus, or hypothalamus. However, the transient expression of 5-HTT on non-serotonergic system was seen in cortical and striatal neuroepithelia at E12 and sensory thalamic pathways at P0-P10. Prominent 5-HTT-im fibers in thalamocortical bundles project from sensory thalamic nuclei through reticular nucleus, internal capsule bundle and form barrels in somatosensory cortices. No 5-HTT-im was seen in glia-like cells using currently available antibody. These observations indicate that 5-HTT is: (a) associated preferentially with 5-HT neurons in brainstem, (b) temporally co-expressed with 5-HT in 5-HT neurons, (c) expressed on axons prior to synaptical sites at target neurons, which strongly indicates a volumic (extrasynaptic) transmission, (d) expressed in non-5-HT neurons within a specific window, which may affect the development of the systems "borrowing" the 5-HT. The early appearance of 5-HTT may also endow functionality as well as vulnerabilities of 5-HT, sensory thalamic, and cortical neurons to 5-HTT targeting drugs during pregnancy and after birth.

Innate differences of neuropeptide Y (NPY) in hypothalamic nuclei and central nucleus of the amygdala between selectively bred rats with high and low alcohol preference

BACKGROUND

Neuropeptide Y (NPY) is a neuropeptide that has been demonstrated to produce anxiolytic effects when administered centrally. To examine the hypothesis that NPY might play a role in alcohol-seeking behavior, this study took advantage of the genetic differences of the alcohol-preferring (P) rats and alcohol-nonpreferring (NP) rats, as well as the high alcohol-drinking (HAD) rats and low alcohol-drinking (LAD) rats, in voluntary alcohol consumption to examine if NPY neurons in the brains differ between these selected lines.

METHODS

The NPY immunoreactivity (NPY-I) was measured using an established radioimmunohistochemical assay in discrete brain structures including the paraventricular hypothalamic nucleus (PVN), arcuate nucleus (ARC), and central nucleus of the amygdala (CeA).

RESULTS

The quantitative data indicated that there was more NPY-I in the PVN and ARC of P rats than NP rats, whereas there was less NPY-I in the PVN and ARC of HAD rats than LAD rats. However, the NPY-I in the CeA was less in both the P and HAD rats than in the NP and LAD rats, respectively. Therefore, the data indicate that there are innate differences in the NPY-I in the brain between selectively bred rats with high and low alcohol preference.

CONCLUSION

Because both P rats and HAD rats have high alcohol preference, the disparate finding between these two lines of rats suggests that the hypothalamic NPY neurons are probably not associated with alcohol preference. In contrast, consistent findings in the CeA of both P rats and HAD rats suggest that NPY in the CeA of P and HAD rats may contribute to the regulation of alcohol consumption. This is substantiated by a recent report showing that NPY-knockout mice drink significantly more ethanol, and transgenic mice that overexpress the NPY gene drink less alcohol, than wild-type mice. Together, the findings support the notion that NPY agonists that would enhance NPY function in the amygdala might be useful for the treatment of anxiety and alcoholism.

Infectious disease surveillance in China

A national system of infectious disease surveillance was established in 1959 in China. Now it consists of three subunits, namely, national disease reporting system (NDRS), nationwide disease surveillance points (DSPs), and surveillance network for specific infectious diseases. There are 35 notifiable infectious diseases, which are divided into Classes A, B, and C. The functions of the surveillance include explaining the natural history of infectious diseases, describing the distribution of case occurrence, triggering disease-control effort, monitoring epidemic of infectious diseases during natural disasters, predicting and controlling epidemics and providing the base of policy adjustment.

An anaerobic, intrachamber incubator for growth of Methanosarcina spp. on methanol-containing solid media

To simplify the incubation of Methanosarcina spp. on solid agar medium, a two-port, manual, rectangular air lock was modified to serve as an anaerobic incubator. In one operation, it is possible to incubate 153 petri plates, the equivalent of 11 standard anaerobic jars, with plating efficiencies identical to those of traditional protocols.

A genetic system for Archaea of the genus Methanosarcina: liposome-mediated transformation and construction of shuttle vectors

New methods that allow, for the first time, genetic analysis in Archaea of the genus Methanosarcina are presented. First, several autonomously replicating plasmid shuttle vectors have been constructed based on the naturally occurring plasmid pC2A from Methanosarcina acetivorans. These vectors replicate in 9 of 11 Methanosarcina strains tested and in Escherichia coli. Second, a highly efficient transformation system based upon introduction of DNA by liposomes has been developed. This method allows transformation frequencies of as high as 2 x 10(8) transformants per microgram of DNA per 10(9) cells or approximately 20% of the recipient population. During the course of this work, the complete 5467-bp DNA sequence of pC2A was determined. The implications of these findings for the future of methanoarchaeal research are also discussed.

Molecular, genetic, and biochemical characterization of the serC gene of Methanosarcina barkeri Fusaro

The Methanosarcina barkeri serC gene, encoding phosphoserine aminotransferase, was cloned by complementation of an Escherichia coli serC mutant, and its nucleotide sequence was determined. The M. barkeri SerC protein shares significant homology with other known SerC proteins. E. coli serC hosts carrying the cloned gene express phosphoserine aminotransferase activity, verifying the function of this gene.

Mesolimbic dopamine system in alcohol-preferring rats

The mesolimbic dopamine system of the brain, in particular the nucleus accumbens (Acb), is long known to be involved in reward behavior. When compared with the alcohol-nonpreferring NP rats, the alcohol-preferring P rats exhibit lower dopamine (DA) levels in the Acb as well as in other forebrain areas (20). In the present study, the DA innervation density, as determined by tyrosine hydroxylase (TH) immunostaining, was found lower in the selective cingulum cortex and the shell of the Acb of the P compared with that of NP rats. These structures cluster in the medial aspect of the mesolimbic system. There were no differences in other major DA mesolimbic brain regions. The subpopulation of DA neurons in the ventral tegmental area (VTA) projecting to the Acb was found to be smaller in the P than in the NP rats, as shown by horseradish peroxidase tracing and TH immunocytochemistry double staining. However, the total number of the DA neurons in the VTA, the major mesolimbic DA center, was found to be similar in the P and NP rats. These results indicate a selective reduction of catecholaminergic innervation in the dopaminergic medial mesolimbic system in the P rats and suggest that the P and NP rat lines should be a useful model for the investigation of DA involvement in alcohol drinking as well as other reinforced behaviors.

Study of gastric and gallbladder kinetics with real-time ultrasonography in cases of functional dyspepsia

Gastric and gallbladder emptying in 113 patients with functional dyspepsia (FD) were evaluated by real-time ultrasonography (RUS) after a liquid-fat meal by the patients, and compared with 15 healthy volunteers. The results showed that in FD group 69 patients (61.06%) had delayed gastric emptying, and 28 patients (24.77%) had gallbladder hypokinesia. Among them both delayed gastric emptying and gallbladder hypokinesia were found in 11 patients (9.7%), 44 patients (38.93%) had normal gastric emptying and 85 patients (75.22%) had normal gallbladder emptying.

[Delayed gastric liquid emptying in the patients with gastroesophageal reflux disease]

Although there were many reports on gastric emptying in patients with gastroesophageal reflux disease (GERD) in western country, there was no scientific paper about it in Chinese. In 22 cases of GERD, diagnosed by clinical manifestations, endoscopy, histology and 24-hour pH monitoring in the distal portion of esophagus, gastric liquid emptying was measured by using absorption test. The results suggested that the mean time to reach the peak of the serum paracetamol level after taking 500ml water was 34.02 +/- 9.09 min. in 13 healthy adults and 51.14 +/- 23.35 min. in 22 cases of GERD. The difference between the two groups was significant (P < 0.02). Among these 22 patients, 12(54.54%) had delayed gastric emptying, 1 rapid and 9 normal. Our data confirmed that gastric liquid emptying was delayed in some patients with GERD.

Imidazo[1,2-b]pyridazines. XIV. Syntheses and Central Nervous System Activities of Some 6-(Methoxy-, dimethoxy-, methylenedioxy-, chloro- and fluoro-)-3-alkoxy-2-phenyl(and substituted phenyl)imidazo[1,2-b]pyridazines

Syntheses are reported for 28 new 3-alkoxy-6-(3′-methoxy-,3′,4′-dimethoxy, 3′,4′-methylene-dioxy-, 2′- and 4′-chloro- and 4′-fluoro-benzylamino)-2-phenyl(and substituted phenyl) imidazo -[1,2-b] pyridazines from the corresponding 6-substituted pyridazin-3-amine 2-oxides with α- bromoacetophenones, followed by alkylation of the intermediate 3-hydroxyimidazo[1,2-b] pyridazines. In tests of the ability of these compounds to displace [3H]diazepam from rat brain membrane, 3-(2′-ethoxyethoxy)-6(3′-methoxybenzylamino)-2-phenyl- and 6(3′,4′-methylenedioxybenzylamino )-2-(3″,4″-methylenedioxyphenyl)-3-methoxy-imidazo[1,2-b] pyridazine bound most strongly, with IC50 values of 1nM.

[Measurement of gastric emptying in non-ulcer dyspepsia]

Using real-time ultrasonography, we monitored gastric emptying indirectly in 26 cases of non-ulcer dyspepsia (NUD) and 13 healthy adults by determining the anteroposterior gastric measurement of a single section of the stomach in the corpus fundus immediately after drinking 500 ml water and then every 10 min. for five times. The average time for 50% gastric emptying in NUD patients (36.46 +/- 13.13, x +/- s) was longer than that in healthy adults (23.54 +/- 5.93), but the half time of gastric emptying in male with NUD was not significantly different as compared with that in male controls and female patients of NUD.

[Effects of beta-agkistrodotoxin on synaptic transmission in toad sympathetic ganglia]

The effects of beta-agkistrodotoxin (beta-AgTX) on synaptic transmission of the toad sympathetic ganglia were investigated by intracellular recording techniques. Superfusion of beta-AgTX (30 microgram/ml, 5-15 min) reversibly inhibited the cholinergic fast excitatory postsynaptic potential (f-EPSP, n = 16) and the fast components of acetylcholine (ACh) potential induced by micropressure administration of ACh (n = 24). Comparison of beta-AgTX effect in the same cell group showed significantly different inhibition rates on f-EPSP (77.2 +/- 27.7%) and ACh potential (25.5 +/- 17.5%) (n = 6, P less than 0.01, F test). During application of beta-AgTX (30 or 50 micrograms/ml) for 15-30 min, no detectable change was found in non-cholinergic late slow EPSPs (n = 22). The results suggest that beta-AgTX selectively inhibits the cholinergic transmission of the toad sympathetic ganglia by both presynaptic and postsynaptic mechanism.

Imidazo[1,2-b]pyridazines. X. Syntheses and Central Nervous System Activities of Some 3-(Acetamido, benzamido, substituted benzamido or dimethylamino)methyl-2-(phenyl or substituted phenyl)-6-(halogeno, alkylthio, alkoxy, phenylthio, phenoxy, benzylthio or benzyloxy)imidazo[1,2-b]pyridazines

Syntheses of some 3-( acetamido, benzamido , substituted benzamido or dimethylamino)methyl-2-(phenyl or substituted phenyl)-6( halogeno, alkylthio, alkoxy, phenylthio, phenoxy , benzylthio or benzyloxy ) imidazo [1,2-b] pyridazines from the 3-unsubstituted analogues are described. The IC50 values (or percentage displacements) are reported and discussed for the displacement of [3H]diazepam from rat brain membrane by each of these compounds. .The 3-benzamidomethyl compounds were generally the most active; of these, 3-benzamidomethyl-2-(3',4'-methylenedioxyphenyl)-6-methylthioimido[1,2-b] pyridazine showed outstanding activity with IC50 2 nM .

Imidazo[1,2-b]pyridazines. XII. Syntheses and Central Nervous System Activities of Some Substituted Imidazo[1,2-b]pyridazines and Related Imidazo[1,2-a]pyridines, Imidazo[1,2-a]pyrimidines and Imidazo[1,2-a]pyrazines

Syntheses are reported for some 6-chloro(alkoxy,alkylthio and pheny1thio)-3-benzamidomethyl-(acetamidomethyl and methoxy)-2-arylimidazo[1,2-apyridines and some corresponding imidazo- [1,2- b]pyridazines, imidazo[1,2-a[pyrimidines and imidazo[l,2-a]pyrazines. IC50 values (or percentage displacement) are reported and discussed for the displacement of [3H]diazepam from rat brain membrane by each of these compounds. The imidazo[l,2-a[pyridines were generally slightly less potent than the imidazo[l,2- b]pyridazines but considerably more potent than the corresponding imidazo[1,2-a]pyrimidines or imidazo[1,2- a[pyrazines. Substitution of a 2-aryl group by a 2-alkyl group in imidazo[l,2- b]pyridazines led to a significant loss of activity.

Imidazo[1,2-b]pyridazines. XI. Syntheses and Central Nervous System Activities of Some 6-(N-Benzyl-N-methylamino)-3-methoxy-2-phenyl(and substituted phenyl)imidazo[1,2-b]pyridazines

Syntheses are reported for 196-(N-benzyl-N-methylamino )-3-methoxy-2-phenyl(and substituted phenyl or pyridinyl ) imidazo [1,2-b] pyridazines from 6-(N-benzyl-N-methylamino)pyridazin-3- amine 2-oxide. The ability of each of these compounds to displace [3H]diazepam from rat brain membrane preparations was measured and the IC50 values (or percentage displacements) are reported and discussed. 6-(N-Benzyl-N-methylamino )-3-methoxy-2-phenylimido[1,2-b]pyridine was about half as active as its 6-bemylamino analogue, and the most active compound was 6-(N-benzyl-N-methylamino )-2-(2'-fluorophenyl)-3-methoxyimido[1,2-b] pyridazine with IC50 9.8 nM.

Imidazo[1,2-b]pyridazines. XIII. Syntheses and Central Nervous System Activities of Some 2-Benzyl(phenethyl, biphenyl-4'-yl, 6'-methylnaphthalen-2'-yl, t-Butyl and cyclohexyl)-3-methoxy(acylaminomethyl and dimethylaminomethyl)-6-(variously substituted)imidazo[1,2-b]pyridazines

6-(Variously substituted)-3-methoxy(unsubstituted, dimethylaminomethyl, acetamidomethyl and benzamidomethy1)-2-benzyl(phenethyl, biphenyl-4'-yl, 6'-methylnaphthalen-2'-yl, t-butyl and cyclohexyl)imidazo[1,2-b] pyridazines have been prepared and examined for activity in the central nervous system. Of these, 2-benzyl-3-methoxy-6-(3'-methoxybenzylamino) imidazo[1,2-b]pyridazine (IC50 88nM) bound most strongly to rat brain membrane. In general, the order of activity for groups at the 2-position was Ph > PhCH2 > PhCH2CH2 > C6H4Ph-p, 6'-methylnaphthalen-2'-yl, c-C6H11 or But.