Whole-cell biosensing of 3-chlorocatechol in liquids and soils

A rapid and sensitive technique is needed to analyze water and soils for chlorocatechols, common environmental pollutants produced from wood pulp chlorination and other processes. The soil bacteria Pseudomonas putida, harboring plasmid pSMM50R-B', selectively express beta-galactosidase in response to 3-chlorocatechol in pure water samples. The objective of the study was to determine whether background matrices in fresh water, sea water, soils, and organic solvents interfered with 3-chlorocatechol analysis by use of a bacteria-sensing system and by high-performance liquid chromatography (HPLC). Although 3-chlorocatechol detection by HPLC was not substantially affected by the background composition of aqueous or organic solvents, HPLC was ineffective in the analysis of contaminated soils due to irreversible contaminant sorption. Whereas detection by the bacteria-sensing system was reduced in the presence of aqueous and organic solvents, interferences could be reduced by sample dilution. 3-Chlorocatechol was detected when the bacteria were added directly to contaminated soils, suggesting that the organism enhanced desorption or had access to the sorbed compounds. Results indicate that the bacteria-sensing system has wide application for detection of 3-chlorocatechols in environmental samples, especially in soils where extraction and HPLC analysis are not efficient due to extensive contaminant sorption.

Effects of tumors on inhaled pharmacologic drugs: II. Particle motion

Computer simulations were conducted to describe drug particle motion in human lung bifurcations with tumors. The computations used FIDAP with a Cray T90 supercomputer. The objective was to better understand particle behavior as affected by particle characteristics, airflow conditions, and disease-modified airway geometries. The results indicated that increases in particle sizes, breathing intensities and tumor sizes could enhance drug deposition on the tumors. The modeling suggested that targeted drug delivery could be achieved by regulating breathing parameters and designing (selecting physical features of) aerosolized drugs. We present the theoretical work as a step towards improving aerosol therapy protocols. Since modeling describes factors affecting dose, it is complementary to considerations of the molecular aspects of drug formulation and pharmacokinetics.

Effects of tumors on inhaled pharmacologic drugs: I. Flow patterns

Lung carcinomas are now the most common form of cancer. Clinical data suggest that tumors are found preferentially in upper airways, perhaps specifically at carina within bifurcations. The disease can be treated by aerosolized pharmacologic drugs. To enhance their efficacies site-specific drugs must be deposited selectively. Since inhaled particles are transported by air, flow patterns will naturally affect their trajectories. Therefore, in Part I of a systematic investigation, we focused on tumor-induced effects on airstreams, in Part II (the following article [p. 245]), particle trajectories were determined. To facilitate the targeted delivery of inhaled drugs, we simulated bifurcations with tumors on carinas using a commercial computational fluid dynamics (CFD) software package (FIDAP) with a Cray T90 supercomputer and studied effects of tumor sizes and ventilatory parameters on localized flow patterns. Critical tumor sizes existed; e.g., tumors had dominant effects when r/R > or = 0.8 for bifurcation 3-4 and r/R > or = 0.6 for bifurcation 7-8 (r = tumor radius and R = airway radius). The findings suggest that computer modeling is a means to integrate alterations to airway structures caused by diseases into aerosol therapy protocols.

A catalytic antibody produces fluorescent tracers of gap junction communication in living cells

The antibody 38C2 efficiently catalyzed a retro-Michael reaction to convert a novel, cell-permeable fluorogenic substrate into fluorescein within living cells. In vitro, the antibody converted the substrate to fluorescein with a k(cat) of 1.7 x 10(-5) s(-1) and a catalytic proficiency (k(cat)/k(uncat)K(m)) of 1.4 x 10(10) m(-1) (K(m) = 7 microm). For hybridoma cells expressing antibody or Chinese Hamster Ovarian (CHO) cells injected with antibody, incubation of the substrate in the extracellular medium resulted in bright intracellular fluorescence distinguishable from autofluorescence or noncatalyzed conversion of substrate. CHO cells loaded with antibody were 12 times brighter than control cells, and more than 85% of injected cells became fluorescent. The fluorescein produced by the antibody traveled into neighboring cells through gap junctions, as demonstrated by blocking dye transfer using the gap junction inhibitor oleamide. The presence of functional gap junctions in CHO cells was confirmed through oleamide inhibition of lucifer yellow transfer. These studies demonstrate the utility of the intracellular antibody reaction, which could generate tracer dyes in specific cells within complex multicellular environments simply by bathing the system in substrate.

Estradiol (E2) elicits SRC phosphorylation in the mouse neocortex: the initial event in E2 activation of the MAPK cascade?

In neocortical explants, E2 activates various signaling components of the MAPK cascade, including B-Raf and MAPK kinase-dependent ERK, suggesting a possible role in the differentiative actions of E2 in the brain. To further characterize the signaling pathways activated by E2, we determined whether c-Src, a member of the Src family of nonreceptor tyrosine kinases and an important modulator of both the MAPK cascade and neuronal differentiation, may play a role in E2 signaling. The present studies show for the first time in the brain that E2 elicits phosphorylation of c-Src on three functionally critical tyrosine residues (Y220, Y423, and Y534), and that this phosphorylation occurs despite disruption of ER alpha (in ER knockout mice). PP2, a Src family kinase inhibitor, suppressed not only E2-induced phosphorylation of c-Src, but ERK phosphorylation as well, suggesting that c-Src may be an upstream regulator of E2 signaling. E2-induced phosphorylation of c-Src is associated with increased tyrosine phosphorylation of Shc, increased association of Shc with Grb2, and induction of Ras, but not Rap1, activation. Together, these data provide evidence that E2 activates a novel c-Src-dependent signal transduction pathway in the developing brain.

Effect of batroxobin on expression of neural cell adhesion molecule in temporal infarction rats and spatial learning and memory disorder

The effect of Batroxobin expression of neural cell adhesion molecule (NCAM) in left temporal ischemic rats with spatial memory disorder was investigated by means of Morri's water maze and immunohistochemical methods. The results showed that the mean reaction time and distance of temporal ischemic rats for searching a goal were significantly longer than those of sham-operated rats and at the same time NCAM expression of left temporal ischemic region was significantly increased. However, the mean reaction time and distance of Batroxobin-treated rats were shorter and they used normal strategies more often and earlier than those of ischemic rats. The number of NCAM immune reactive cells of Batroxobin-treated rats was more than that of ischemic group. In conclusion, Batroxobin can improve spatial memory disorder of temporal ischemic rats and the regulation of the expression of NCAM is probably related to the neuroprotective mechanism.

[Optimization of synthetic culture condition on lignin biodegradation ability of alkaliphilic ligninolytic bacteria using orthogonal experimental design]

The effects of seven single culture factors on lignin biodegradation ability of alkaliphilic ligninolytic bacteria strain 6 in alkaline liquid medium (pH approximately 10.5) with compounded carbons were optimized using orthogonal experiments. The result showed the seven single culture factors promote the activities of Laccase and MnP and the degradation rate of wheat straw lignin in varying degrees. The synthetic result was analysised. The optimal synthetic condition was static culture (10 days culture period), 37 degrees C, the initial pH10.6, 1 g/L sugar (the starting carbons), wheat straw lignin (the second carbons, wheat straw powder 20 g/L, added into on the fourth day after inoculation), 1.2 g/L NH4NO3 (nitrogen), 0.3% detergent T-80, 70 ml medium/250 ml flask.

[Studies on fatty liver, blood glucose and related factors in simple obese children]

OBJECTIVE

To study the prevalence of fatty liver, blood glucose and related factors in simple obese children.

METHODS

Their liver was scanned with B-type ultrasound and fasting blood glucose (with a microassay glucometer), as well as other related morphological and functional indices, were measured in 62 children aged 8 to 11 years, including 32 obese ones and 30 control ones.

RESULTS

Prevalence of fatty liver in obese and control groups was 93.8% and 10%, respectively, with very statistically significant difference (P < 0.01). Blood glucose level in obese and control groups was 5.42 mmol/L and 5.54 mmol/L, respectively, with statistically significant difference (P < 0.05). Proportion of children with normal cardiac function was 62.5% and 93.3%, respectively, in obese and control groups, with significant difference (P < 0.05). The prevalence of fatty liver correlated positively with skin-fold thickness, waist to hip ratio (WHR) and body mass index (BMI), with coefficients of correlation of 0.8786, 0.6256 and 0.8454, respectively (P < 0.01). Blood glucose correlated with skin-fold thickness and BMI positively, with coefficients of correlation of 0.3403 and 0.3155, respectively (P < 0.05). Regression analysis showed that skin-fold thickness and WHR were major risk factor for fatty liver and skin-fold thickness was major risk factor for high blood glucose.

CONCLUSIONS

Simple obesity could cause damage to the liver, glucose metabolism and cardiac function in children, forming the potential risk factors for cardiovascular diseases, diabetes and disturbance of lipid metabolism in adults.

Analysis of genetic alterations in primary nasopharyngeal carcinoma by comparative genomic hybridization

To identify genetic alterations associated with the development and progression of human nasopharyngeal carcinoma (NPC), 57 tumors were analyzed by comparative genomic hybridization (CGH). In 47 cases, chromosomal imbalances were found. Several recurrent chromosomal abnormalities were identified in the present study. The most frequently detected chromosomal gains involved chromosome arms 12q (24 cases, 51%), 4q (17 cases, 36%), 3q (16 cases, 34%), 1q (15 cases, 32%), and 18q (15 cases, 32%). Common regions of gain involved 12q13--q15, 4q12--q21, and 3q21--q26. High-copy-number increases of chromosomal materials were detected in four chromosomal regions, 3q21--q26.2, 4p12--q21, 8p, and 12q14--q15. The most frequently detected loss of chromosomal materials involved chromosome arms 16q (26 cases, 55%), 14q (21 cases, 45%), 1p (20 cases, 43%), 3p (20 cases, 43%), 16p (19 cases, 40%), 11q (17 cases, 36%), and 19p (16 cases, 34%). The most common regions of loss involved 14q24--qter, 1pter--p36.1, 3p22--p21.3, 11q21--qter, and the distal region of 19p. Genomic alterations detected by CGH were compared and found to be largely consistent with those identified in banding analysis and loss of heterozygosity studies. However, several previously unrecognized recurrent alterations were also identified in the present study, including gain of 4q and 18q, and loss of 16q, 14q, and 19p. In addition, gain of 1q, 8q, 18q, and loss of 9q showed a statistically significant association with advanced clinical stages (P < 0.05). Identification of recurrent sites of chromosomal gain and loss identify regions of the genome that may contain oncogenes or tumor suppressor genes, respectively, which may be involved in the tumorigenesis of NPC. Published 2000 Wiley-Liss, Inc.

Fluid dynamics in airway bifurcations: II. Secondary currents

As the second component of a systematic investigation on flows in bifurcations reported in this journal, this work focused on secondary currents. The first article addressed primary flows and the third discusses localized conditions (both in this issue). Secondary flow patterns were studied in two lung bifurcation models (Schreck, 1972) using FIDAP with the Cray T90 supercomputer. The currents were examined at different prescribed distances distal to the carina. Effects of inlet conditions, Reynolds numbers, and diameter ratios and orientations of airways were addressed. The secondary currents caused by the presence of the carina and inclination of the daughter tubes exhibited symmetric, multivortex patterns. The intensities of the secondary currents became stronger for larger Reynolds numbers and larger angles of bifurcation.

Fluid dynamics in airway bifurcations: III. Localized flow conditions

Localized flow conditions (e.g., backflows) in transition regions between parent and daughter airways of bifurcations were investigated using a computational fluid dynamics software code (FIDAP) with a Cray T90 supercomputer. The configurations of the bifurcations were based on Schreck s (1972) laboratory models. The flow intensities and spatial regions of reversed motion were simulated for different conditions. The effects of inlet velocity profiles, Reynolds numbers, and dimensions and orientations of airways were addressed. The computational results showed that backflow was increased for parabolic inlet conditions, larger Reynolds numbers, and larger daughter-to-parent diameter ratios. This article is the third in a systematic series addressed in this issue; the first addressed primary velocity patterns and the second discussed secondary currents.

Fluid dynamics in airway bifurcations: I. Primary flows

The subject of fluid dynamics within human airways is of great importance for the risk assessment of air pollutants (inhalation toxicology) and the targeted delivery of inhaled pharmacologic drugs (aerosol therapy). As cited herein, experimental investigations of flow patterns have been performed on airway models and casts by a number of investigators. We have simulated flow patterns in human lung bifurcations and compared the results with the experimental data of Schreck (1972). The theoretical analyses were performed using a third-party software package, FIDAP, on the Cray T90 supercomputer. This effort is part of a systematic investigation where the effects of inlet conditions, Reynolds numbers, and dimensions and orientations of airways were addressed. This article focuses on primary flows using convective motion and isovelocity contour formats to describe fluid dynamics; subsequent articles in this issue consider secondary currents (Part II) and localized conditions (Part III). The agreement between calculated and measured results, for laminar flows with either parabolic or blunt inlet conditions to the bifurcations, was very good. To our knowledge, this work is the first to present such detailed comparisons of theoretical and experimental flow patterns in airway bifurcations. The agreement suggests that the methodologies can be employed to study factors affecting airflow patterns and particle behavior in human lungs.

Differential regulation of neuropeptide Y receptors in the brains of NPY knock-out mice

To study the effect of NPY deletion on the regulation of its receptors in the NPY knockout (NPY KO) mice, the expression and binding of NPY receptors were investigated by in situ hybridization and receptor autoradiography using (125)I-[Leu(31),Pro(34)]PYY and (125)I-PYY(3-36) as radioligands. A 6-fold increase in Y2 receptor mRNA was observed in the CA1 region of the hippocampus in NPY KO mice, but a significant change could not be detected for Y1, Y4, Y5 and y6 receptors. Receptor binding reveals a 60-400% increase of Y2 receptor binding in multiple brain areas. A similar increase in Y1 receptor binding was seen only in the hypothalamus. These results demonstrate the NPY receptor expression is altered in mice deficient for its natural ligand.

Analysis of genetic alterations in primary nasopharyngeal carcinoma by comparative genomic hybridization

To identify genetic alterations associated with the development and progression of human nasopharyngeal carcinoma (NPC), 57 tumors were analyzed by comparative genomic hybridization (CGH). In 47 cases, chromosomal imbalances were found. Several recurrent chromosomal abnormalities were identified in the present study. The most frequently detected chromosomal gains involved chromosome arms 12q (24 cases, 51%), 4q (17 cases, 36%), 3q (16 cases, 34%), 1q (15 cases, 32%), and 18q (15 cases, 32%). Common regions of gain involved 12q13--q15, 4q12--q21, and 3q21--q26. High-copy-number increases of chromosomal materials were detected in four chromosomal regions, 3q21--q26.2, 4p12--q21, 8p, and 12q14--q15. The most frequently detected loss of chromosomal materials involved chromosome arms 16q (26 cases, 55%), 14q (21 cases, 45%), 1p (20 cases, 43%), 3p (20 cases, 43%), 16p (19 cases, 40%), 11q (17 cases, 36%), and 19p (16 cases, 34%). The most common regions of loss involved 14q24--qter, 1pter--p36.1, 3p22--p21.3, 11q21--qter, and the distal region of 19p. Genomic alterations detected by CGH were compared and found to be largely consistent with those identified in banding analysis and loss of heterozygosity studies. However, several previously unrecognized recurrent alterations were also identified in the present study, including gain of 4q and 18q, and loss of 16q, 14q, and 19p. In addition, gain of 1q, 8q, 18q, and loss of 9q showed a statistically significant association with advanced clinical stages (P < 0.05). Identification of recurrent sites of chromosomal gain and loss identify regions of the genome that may contain oncogenes or tumor suppressor genes, respectively, which may be involved in the tumorigenesis of NPC. Published 2000 Wiley-Liss, Inc.

Metabolic changes in rats with photochemically induced cerebral infarction and the effects of batroxobin: a study by magnetic resonance imaging, 1H- and 31P-magnetic resonance spectroscopy

Metabolic changes in rats with photochemically induced cerebral infarction and the effects of batroxobin were investigated 1, 3, 5 and 7 days after infarction by means of magnetic resonance imaging (MRI), 1H- and 31P-magnetic resonance spectroscopy (MRS). A region of T2 hyperintensity was observed in left temporal neocortex in infarction group and batroxobin group 1, 3, 5 and 7 days after infarction. The volume of the region gradually decreased from 1 day to 7 days after infarction. The ratio of NAA/Cho + Cr in the region of T2 hyperintensity in the infarction group was significantly lower than that in the corresponding region in the sham-operated group 3, 5 and 7 days after infarction respectively (P < 0.05). Lac appeared in the region of T2 hyperintensity in the infarction group 1, 3, 5 and 7 days after infarction, but it was not observed in the corresponding region in sham-operated group at all time points. Compared with the sham-operated group, the ratios of beta ATP/PME + PDE and PCr/PME + PDE of the whole brain in the infarction group were significantly lower 1, 3 and 5 days after infarction respectively (P < 0.05), and the ratio of beta ATP/PCr also was significantly lower 1 day after infarction (P < 0.05). Batroxobin significantly decreased the volume of the region of T2 hyperintensity 1 and 3 days after infarction (P < 0.05), significantly increased the ratio of NAA/Cho + Cr in the region 5 and 7 days after infarction (P < 0.05), significantly decreased the ratios of Lac/Cho + Cr and Lac/NAA in the region 5 and 7 days after infarction (P < 0.05), and significantly increased the ratios of beta ATP/PME + PDE and beta ATP/PCr in the whole brain 1 day after infarction (P < 0.05). The results indicated that the infracted region had severe edema, increased Lac and apparent neuronal dysfunction and death, and energy metabolism of the whole brain decreased after focal infarction, and that batroxobin effectively ameliorated the above-mentioned abnormal changes.

A study on producing monoclonal antibody with one diagnostic marker screened electrophoretically from the urine of individuals infected with Schistosoma japonicum

One diagnostic marker (a glycoprotein with 30kDa) from the urine of individuals infected with S. japonicum was screened with electrophoresis, and used as antigen to produce McAbs. Two lines of McAbs, named NP56 and NP54,were obtained. McAb NP56 was of better immunoreactivity and its immunoglobulin isotype was IgG(2b.) McAb NP56 could react with SEA (soluble egg antigen) and AWA (adult worm antigen) and express on miracidia in eggs of S. japonicum. When determined with NP56 as a probe in indirect ELISA, the sensitivity and specificity of positive urine samples (EPG median 69) was 50% and 80% in original urine samples, and 90% and 100% in concentrated urine samples, respectively. The results above indicated that with established means it is feasible to produce McAb with the diagnostic marker screened electrophoretically from the metabolic product of the individuals infected with this pathogen, and that McAb-NP56 is of potential value in the diagnosis of chronic cases and individuals with light infection with S. japonicum.

[The devitalization of tumor suppressor genes in oral squamous cell carcinoma]

OBJECTIVE

To study the expression of anti-oncogenes nm23, P16, P53 of squamous cell carcinoma within one sample.

METHODS

A total of 27 cases of oral squamous cell carcinoma came from our the First Clinical College, China Medical University from 1997 to 1998, and none of them had the history of radioactivity therapy or chemical therapy. In them, 8 cases were in the early period, and 19 cases were in the late period. 15 cases were male and 12 cases were female. The samples were fixed in formaldehyde solution, embedded with paraffin, sliced in 5 microns, and analysed by ABC immunohistochemistry staining. The first antibodies were anti-P16, anti-nm23, anti-P53 respectively. The criteria of judgment were the following: For nm23, the case that cytoplasm or nucleus were buffy particles or ball was positive. For P16, the case that nucleus were brown was positive, while the case with the light brown cytoplasm and unstained nucleus was negative. The stained nucleus of interstitial cells were treated as the control. For p53, the positive protein product was assembled in the carcinoma cell nucleus, so the nucleus with buffy or brown particles was positive. According to the criteria, 5 high power sights were selected from each case, more than one hundred cells were counted. The case that the positive cells was more than 30 percentage was high expression, and less than 30 percentage was low expression. Two doctors completed the procedure respectively, and only the same results could be qualified.

RESULTS

In the 27 cases, the devitalization of nm23 and p16 was showed in low expression, p53 in high expression. The devitalization rate: p16 was 66.7%, nm23 was 48.1%, and p53 was 25.9%. In 14 cases, combined mutation of two inhibitory genes were seen. 9 cases were p16 and nm23, among them, 4 cases had transferred to cervical lymph nodes (In all the cases, there were 6 cases who had cervical lymph node transference).

CONCLUSION

p16 genetic changes are more often detected in oral squamous cell carcinoma than the other genetic changes; In a large portion of cases, there were combined genetic changes instead of single gene mutation.

[The application of fluorescence in situ hybridization performed on the decolorized G-banding chromosomes in detecting the marker chromosomes of gastric cancer]

OBJECTIVE

Using a rapid, accurate method that detects the marker chromosomes of gastric cancer and enhancing the ability of discriminating complicated chromosome rearrangements of gastric cancer.

METHODS

The improved method of fluorescence in situ hybridization(FISH) performed on the decolorized G-banding chromosome was used.

RESULTS

The changes of two marker chromosomes (M1, M2) of the cell line(SGC-7901) of gastric cancer and one marker chromosomes(M3) of one primary gastric cancer were respectively analyzed by this method. The M1, M2 and M3 had complicated structural chromosome aberrations: del(7)(p15)/del(7)(q22), t(1;3)(p11;q11) and del(7)(q32).

CONCLUSION

This method showed strong signals, low backgrounds and well-repetitions. It may play an important part in exploring the chromosome rearrangements in the process of pathogenesis and development of gastric cancer.

Chlorocatechol detection based on a clc operon/reporter gene system

A sensitive and selective sensing system for chlorocatechols (3-chlorocatechol and 4-chlorocatechol) was developed based on Pseudomonas putida bacteria harboring the plasmid pSMM50R-B'. In this plasmid, the regulatory protein of the clc operon, ClcR, controls the expression of the reporter enzyme beta-galactosidase. When bacteria containing components of the clc operon are grown in the presence of chlorocatechols, ClcR activates the clcA promoter, which is located upstream from the beta-galactosidase gene. Thus, the concentration of chlorocatechols can be related to the production of beta-galactosidase in the bacteria. The concentration of beta-galactosidase expressed in the bacteria was determined by measuring the chemiluminescence signal emitted with the use of a 1,2-dioxetane substrate. ClcR has a high specificity for chlorocatechols and provides the sensing system with high selectivity. This was demonstrated by evaluating several structurally related organic compounds as potential interfering agents. Both 3-chlorocatechol and 4-chlorocatechol can be detected with this sensing system at concentrations as low as 8 x 10(-10) and 2 x 10(-9) M, respectively, using a 2-h induction period. In the case of 3-chlorocatechol, a highly selective sensing system was developed that can detect this species at concentrations as low as 6 x 10(-8) M after a 5-min induction period; the presence of 4-chlorocatechol at concentrations as high as 2 x 10(-4) M did not interfere with this system.

High chromium yeast supplementation improves glucose tolerance in pigs by decreasing hepatic extraction of insulin

Twenty Landrace x Yorkshire cross pigs (body wt, 47.9+/-2.9 kg) were used to evaluate effects of dietary high chromium (Cr) yeast supplementation on plasma kinetics of glucose, insulin and C-peptide. Pigs were provided free access to either a control diet (C) containing 204 microg Cr/kg or a diet supplemented with an additional 200 microg Cr/kg as high Cr yeast (CR) for between 23 and 30 d. After overnight food deprivation, dextrose (500 g/L) was infused through a jugular vein catheter at a dose of 0.5 g glucose/kg body weight with an infusion rate of 10 g glucose/min within 6 min. High Cr yeast supplementation did not affect body weight gain or food intake. There were no differences in fasting plasma concentrations of either glucose or C-peptide, although basal plasma concentration of insulin tended to be higher in pigs fed CR (P<0.10). Plasma glucose concentrations were lower (P<0.01) at postinfusion times 5, 10, 15 and 20 min in pigs fed CR. Plasma insulin concentrations in pigs fed CR were higher (P<0.05) at 2 and 0 min before the completion of dextrose infusion. However, the increase in plasma insulin concentrations was not accompanied by a comparable elevation in plasma C-peptide concentrations. The 30-min (postinfusion) area of plasma glucose concentrations tended to be lower (P<0.10) in pigs fed CR, but there were no differences in 30-min areas of either plasma insulin or plasma C-peptide concentrations between treatments. Plasma clearance rates of glucose, insulin and C-peptide were higher and their half-lives shorter (P<0.05) in pigs fed CR. In conclusion, dietary high Cr yeast supplementation improved glucose tolerance, possibly through a decrease in hepatic extraction of insulin.

[Interaction between biofilm formed by Pseudomonas aeruginosa and antibacterial agents]

We hypothesized that bacterial biofilm formation could be an important factor that make some infection intractable. Interaction of P. aeruginosa biofilm with antibactial agents was examined in vitro.

METHODS

P. aeruginosa incubated for 6 days in a saline-teflon system formed biofilm on the surfaces of the teflon piece. The biofilm were characteried by dense colonization of bacteria and thick membranous structure that covered the colonies, it was observed with a scanning electron microscopy. CPFX, CAM, ROX and Herba Andrographitis were added to the biofilm bacteria.

RESULTS

The rate of survial of the floating bacteria decreased to 0.02% after 4 hours of contact with 2MIC of Ciprofloxacin (CPFX), but that of biofilms was 41% When 10 micrograms/mL of Clarithromycin (CAM per mL was combined with CPFX, the survial rate for the biofilm bacteria decreased to 0.2%. When 12 micrograms/mL of Roxithromycin (ROX) was combined with CPFX, the survial rate for the biofilm bacteria decreased to 0.5%. When 0.05 g of Burm. f. per mL was combined with CPFX the survial rate for the biofilm bacteria decreased to 2.7%.

CONCLUSION

We conclude that biofilm bacteria are much more resistant to CPFX than the floating bacteria. The combination of CPFX and CAM, ROX HA were more effective in decreasing the biofilm bacteria survial rate than CPFX alone. The results suggest that the combination of CPFX and CAM, ROX, HA can be one of the therapeutic manauvers against biofilm bacteria.

Anti-fecundity immunity in mice immunized with anti-idiotypic monoclonal antibody NP30 of Schistosoma japonicum

OBJECTIVE

To observe the effects of anti-fecundity and anti-embryonation immunity of anti-idiotypic monoclonal antibody NP30 of Schistosoma japonicum on female adult worm.

METHODS

The active immunization of C57BL/6 mice was conducted by means of three intraperitoneal injections of NP30. The control group was injected with SP2/0 ascites intraperitoneally.

RESULTS

On the twenty-seventh day after challenge infection, the number of eggs in the liver tissue and in uterus of the group immunized with NP30 decreased by 30.91% and by 38.55%, respectively. On the thirty-ninth day after the challenge infection, the number of mature eggs in the liver tissue of the group immunized with NP30 decreased by 66.63% and the number of dead eggs increased by 60.66%.

CONCLUSIONS

NP30, with which mice were actively immunized, possesses double effects of anti-fecundity and anti-embryonation immunity on female adult worm of Schistosoma japonicum, therefore it can be used as a promising candidate of anti-pathologic vaccine molecule against Schistosomiasis japonica.

[Induction of apoptosis in various cancer cell lines by human soluble TRAIL expressed in Escherichia coli]

OBJECTIVE

To investigate the induction of apoptosis by human soluble TRAIL expressed in Escherichia coli and analyze its relationship with p53 in various cancer cell lines, especially the solid tumor.

METHODS

TRAIL codons 114 approximately 281 were amplified by polymerase chain reaction. The soluble segment was expressed in Escherichia coli JF1125, refolded and purified. Induction of apoptosis was assessed by examination of morphological changes under electron microscope and quantified by FACS analysis. The mutation of p53 in employed cell lines was detected by immunohistochemistry.

RESULTS

By multi-step purification, the purity of human soluble TRAIL exceeded 90%. Induction of apoptosis by the product exhibited a marked increase in human breast cancer cell line MCF-7, HeLa cervical carcinoma cells and hepatocellular carcinoma cell lines SMMC7721, BEL7402, and BEL7405. The mutation of p53 in employed cell lines was positive in aforementioned cell lines.

CONCLUSION

The human soluble TRAIL expressed in Escherichia coli has similar activity to that generated in cells to induce apoptosis in various cancer cell lines, and acts independently of p53.

[Clinical observation of taxotere in the treatment of advanced non-small-cell lung cancer and breast cancer]

OBJECTIVE

To observe the response rate and toxic reaction of taxotere in the treatment of advanced NSCLC and breast cancer.

METHODS

A total of 24 cases was included in the study. Taxotere 75 mg/m2 i.v. drip for 1 hour; dexamethasone 8 mg bid 24 hour before taxotere, and continued for 3 days. For NSCLC, the taxotere was combined with DDP 90 mg/m2; for breast cancer, it was combined with ADM 40 mg/m2. The second treatment cycle was given after 3 weeks. At last 2 cycles were given.

RESULTS

In 15 NSCLC patients, there were 6 PR, 7 NC and 2 PD. In 9 breast cancer patients, there were 2 CR, 6 PR and 1 NC. The major toxic reactions were neutropenia, diarrhea, fatigue, muscle pain and alopecia. Grade 3 and grade 4 neutropenia occurred in 9 and 4 cases, respectively. Decrease in hemoglobin and thrombocytopenia were mild. Diarrhea occurred in 19 cases and allergic reaction in 1 case.

CONCLUSION

Taxotere is effective in the combined treatment of advanced NSCLC and breast cancer. The toxic reactions are tolerable.

Estrogen-induced activation of the mitogen-activated protein kinase cascade in the cerebral cortex of estrogen receptor-alpha knock-out mice

We have shown previously in the developing cerebral cortex that estrogen elicits the rapid and sustained activation of multiple signaling proteins within the mitogen-activated protein (MAP) kinase cascade, including B-Raf and extracellular signal-regulated kinase (ERK). Using estrogen receptor (ER)-alpha gene-disrupted (ERKO) mice, we addressed the role of ER-alpha in mediating this action of estrogen in the brain. 17beta-Estradiol increased B-Raf activity and MEK (MAP kinase/ERK kinase)-dependent ERK phosphorylation in cerebral cortical explants derived from both ERKO and their wild-type littermates. The ERK response was stronger in ERKO-derived cultures but, unlike that of wild-type cultures, was not blocked by the estrogen receptor antagonist ICI 182,780. Surprisingly, both the ER-alpha selective ligand 16alpha-iodo-17beta-estradiol and the ER-beta selective ligand genistein failed to elicit ERK phosphorylation, suggesting that a different mechanism or receptor may mediate estrogen-induced ERK phosphorylation in the cerebral cortex. Interestingly, the transcriptionally inactive stereoisomer 17alpha-estradiol did elicit a strong induction of ERK phosphorylation, which, together with the inability of the ER-alpha- and ER-beta-selective ligands to elicit ERK phosphorylation, and of ICI 182,780 to block the actions of estradiol in ERKO cultures, supports the hypothesis that a novel, estradiol-sensitive and ICI-insensitive estrogen receptor may mediate 17beta-estradiol-induced activation of ERK in the brain.

[Relationship of bcl-2 gene expression with cell proliferation and apoptosis in human gliomas]

OBJECTIVE

To investigate the relationship of bcl-2 gene expression level in human gliomas with the malignant degree, cell proliferative activity and apoptosis of the tumors.

METHODS

The expression of bcl-2 mRNA, bcl-2 protein and proliferating cell antigen, and the apoptosis in sixty-nine human glioma specimens with different malignant grades were studied using in situ hybridization, in situ cell death detection (TUNEL method) and immunohistochemistry.

RESULTS

Of the 69 gliomas, 64 (92.8%) and 60 (87.0%) expressed bcl-2 mRNA and bcl-2 protein, respectively. The expression levels of bcl-2 mRNA and bcl-2 protein were correlated positively with each other (r(s) = 0.999, P < 0.01). The expression levels of bcl-2 mRNA and bcl-2 protein were both higher in WHO grade IV gliomas than in grade III gliomas, and the expression was lowest in grade I-II gliomas (P < 0.02 approximately 0.001). With the increase in the expression of bcl-2 protein, the cell proliferating activity increased and apoptosis decreased in the tumor cells. There was significant difference of cell proliferation and apoptosis between + + + group and + + group of bcl-2 protein expression (P < 0.05) as well as between both the former groups, and the negative and + group (P < 0.01) respectively.

CONCLUSIONS

Over-expression of bcl-2 gene inhibits apoptosis of glioma cells, and the inhibitory intensity increases with the ascending of bcl-2 gene expression level in glioma cells. Both the decrease in apoptosis caused by bcl-2 gene over-expression and the excessive cell proliferation promoted by other gene abnormalities may result in unlimited cell accumulation, which may play an important role in the development and malignant progression of gliomas.

Mathematical Model of Airflow in the Lungs of Children II: Effects of Ventilatory Parameters

In an effort to develop more effective aerosol therapy procedures, we examined airflow patterns in the lung of a child (age four years). In particular, we were concerned with how ventilatory parameters (i.e., breathing rate and tidal volume) affected the patterns of airflow around tumors. To conduct the study, a computational fluid dynamics package, FIDAP was used to define a model lung. The results of simulations show the extent to which changing ventilatory parameters can affect flow patterns in the neighborhood of the tumors as well as drug distribution throughout the lung.

Engraftment and growth of patient-derived retinoblastoma tumour in severe combined immunodeficiency mice

The development of an in vivo model of retinoblastoma could be important for studying its biological behaviour and developing novel therapeutic strategies. We examined the ability of patient-derived retinoblastoma cells to grow and disseminate in severe combined immunodeficiency CB-17-SCID mice after subcutaneous (s.c.) inoculation without conditioning treatment. 24/30 (80%) of patient-derived tumours engrafted and grew as s.c. nodules in SCID mice. Whilst most xenografted tumours appeared to be localised, by PCR assay a positive DNA band of human minisatellite region (YNZ.22) was determined in the bone marrow of 19/25 (76%), in the spleen of 14/25 (56%) and in the liver of 16/25 (64%) mice, respectively, indicating dissemination to distant organs. Cytogenetic analysis demonstrated i(6p) in 5/12 (42%) and trisomy 1 or 1q abnormalities in 8/12 (67%) of the xenografted tumour samples studied, respectively, suggesting that retinoblastoma tumour cells maintain their cytogenetic abnormalities following adoptive growth in SCID mice. In this report we demonstrate the ability to propagate human primary retinoblastoma cells in SCID mice after s.c. inoculation and suggest the possibility of using the SCID mouse model to study the intrinsic biological behaviour of human retinoblastoma and to develop novel therapeutic strategies in the treatment of this disease.

Mathematical Model of Airflow in the Lungs of Children I: Effects of Tumor Sizes and Locations

To contribute to the development of more effective aerosol therapy protocols in pediatric medicine, we examined airflow patterns in the lung of a four-year-old child. In particular, we addressed how the presence of tumors in airways affected the character of airflow patterns. To study the effects of tumors we employed a computational fluid dynamics package, FIDAP, to define flow conditions within a model lung. The results indicated that tumors have a pronounced affect on both (i) localized velocity profiles in airways and (ii) bulk flow distribution within the lung. By identifying the effects of physical factors on flow conditions the findings will lead to improved drug delivery regimens.

Identification of S-(n-butylcarbamoyl)glutathione, a reactive carbamoylating metabolite of tolbutamide in the rat, and evaluation of its inhibitory effects on glutathione reductase in vitro

Tolbutamide (TOLB), a widely used hypoglycemic agent in the therapy of non-insulin-dependent diabetes mellitus, has been reported to be teratogenic and/or embryotoxic in several animal species and humans. It has been proposed that the teratogenic effects of TOLB are linked to drug-mediated depletion of glutathione (GSH) through inhibition of the enzyme glutathione reductase (GR), although the mechanism by which this inhibition occurs remains unknown. In the study presented here, rats were injected with TOLB (200 mg/kg ip), and bile was collected for analysis by liquid chromatography/tandem mass spectrometry (LC/MS/MS). This led to the identification of S-(n-butylcarbamoyl)glutathione (SBuG), a reactive GSH conjugate derived from n-butyl isocyanate, as a minor metabolite of TOLB in bile. Upon incubation of SBuG (0.25-1.0 mM) with GR from either yeast or bovine intestinal mucosa in the presence of NADPH (0.20 mM), enzyme activity was lost in a time- and concentration-dependent manner. No inhibition was observed when NADPH was omitted from incubations, or when the natural substrate for the enzyme, glutathione disulfide (GSSG, 0.05 mM), was added. TOLB itself did not inhibit GR over the concentration range of 0.8-2.0 mM. It is concluded that metabolic activation of TOLB in vivo leads to the generation of reactive intermediates (n-butyl isocyanate and SBuG) which carbamoylate and thereby inhibit GR. At critical periods of organogenesis, the resulting perturbation of GSH homeostasis in exposed tissues may play a key role in the teratogenic and/or embryotoxic effects of TOLB.

[Comparative genomic hybridization analysis of primary gastric carcinomas]

OBJECTIVE

To investigate whether unknown genes are involved in the tumorigenesis of gastric cancer.

METHODS

Fourty-three primary gastric carcinomas were analyzed by comparative genomic hybridization(CGH).

RESULTS

A gain in chromosome 3p(8/43), 8q(8/43), 20[20(9/43), 20p(7/43), 20q(4/43)], 12q (16/43), and 13q(12/43) was observed while a loss of 19[19(15/43), 19p (13/43)], 17[17(8/43), 17p(10/43)], 16(10/43) and 1p(11/43) was discovered.

CONCLUSION

There were characteristic changes in 3p, 8q, 20, 12q, 13q, 19, 17, 16, and 1p in gastric carcinoma, and some unknown genes located in the above regions might be of importance to gastric carcinoma pathogenesis.

Restricting the mobility of Gs alpha: impact on receptor and effector coupling

The alpha-subunit of the stimulatory G protein, Gs, has been shown to dissociate from the plasma membrane into the cytosol following activation by G protein-coupled receptors (GPCR) in some experimental systems. This dissociation may involve depalmitoylation of an amino-terminal cysteine residue. However, the functional significance of this dissociation is not known. To investigate the functional consequence of Gs alpha dissociation, we constructed a membrane-tethered Gs alpha (tetGs alpha), expressed it in Sf9 insect cells, and examined its ability to couple with the beta(2) adrenoceptor and to activate adenylyl cyclase. Compared to wild-type Gs alpha, tetGs alpha coupled much more efficiently to the beta 2 adrenoceptor and the D1 dopamine receptor as determined by agonist-stimulated GTP gamma S binding and GTPase activity. The high coupling efficiency was abolished when Gs )alpha was proteolytically cleaved from the membrane tether. The membrane tether did not prevent the coupling of tetGS alpha to adenylyl cyclase. These results demonstrate that regulating the mobility of Gs alpha relative to the plasma membrane, through fatty acylation or perhaps interactions with cytoskeletal proteins, could have a significant impact on receptor-G protein coupling. Furthermore, by enabling the use of more direct measures of receptor-G protein coupling (GTPase activity, GTP gamma S binding), tetGS alpha can facilitate the study for receptor-G protein interactions.

[Observations on expression of c-fos and c-myc genes and activity of PDGFBB autocrine loop in 67 human gliomas]

OBJECTIVE

To investigate the variance of expression of c-fos and c-myc genes and the activity of platelet-derived growth factor (PDGF) BB autocrine loop in human gliomas as well as their relationship.

METHODS

In situ hybridization and immunohistochemistry were used to study 67 human glioma specimens of different grades.

RESULTS

The incidences, of positive expression for c-fos mRNA, c-fos protein, c-myc mRNA and c-myc protein were 100% (67/67), 100% (67/67), 85.1% (57/67) and 83.6% (56/67) respectively. There was significant positive correlation between the positive cell densities of c-fos mRNA (92.49 +/- 33.87) and c-fos protein (91.64 +/- 38.11), and of c-myc mRNA (72.70 +/- 40.56) and c-myc protein (71.49 +/- 41.11, r = 0.917 - 0.988, P < 0.001). All of them also increased correspondingly with the malignant degree of the tumors and level of PDGFB mRNA expression in the tumor cells (P < 0.05 - 0.01). Not only were the positive cell densities of PDGF alpha receptor (58.46 +/- 28.77), PDGF beta receptor (63.03 +/- 31.63) and phosphotyrosine protein (68.25 +/- 29.30) correlated positively with one another (r = 0.827 - 0.896, P < 0.001), but they also all correlated positively with the positive cell densities of PDGFB mRNA, c-fos mRNA, c-fos protein, c-myc mRNA and c-myc protein respectively (r = 0.615 - 0.888, P < 0.001).

CONCLUSIONS

The abnormally increased activity of the PDGFBB autocrine loop possibly upregulated the overexpression of c-fos and c-myc genes in glioma cells and suggested that c-fos and c-myc proteins probably played an important role as downstream response factors in the signaling pathway in which PDGFBB could induce gliocyte transformation and glioma development.

Arachidonic acid amide inhibitors of gap junction cell-cell communication

A series of arachidonic acid amides including anandamide and arachidonamide that act as potent inhibitors of the rat glial cell gap junction is described.

[Simultaneous determination of phosphorus in hair by ICP-AES]

A useful ICP-AES method for the determination of microelements P, Zn, Cu, Fe, Ca, Mg, Pb, Mn and Al in hair is described. The JY38 spectrometer in the JY70PII ICP-AES system,equipped with a 3600 g/mm holographic diffraction grating (1 m focal length) was used for the determination of phosphorus. The detection limit value (at 3 standard deviations of background) for spectral line 213.618 nm is 0.022 microg x mL(-1).

Estrogen-induced activation of mitogen-activated protein kinase in cerebral cortical explants: convergence of estrogen and neurotrophin signaling pathways

We have shown that estrogen elicits a selective enhancement of the growth and differentiation of axons and dendrites (neurites) in the developing CNS. We subsequently demonstrated widespread colocalization of estrogen and neurotrophin receptors (trk) within developing forebrain neurons and reciprocal transcriptional regulation of these receptors by their ligands. Using organotypic explants of the cerebral cortex, we tested the hypothesis that estrogen/neurotrophin receptor coexpression also may result in convergence or cross-coupling of their signaling pathways. Estradiol elicited rapid (within 5-15 min) tyrosine phosphorylation/activation of the mitogen-activated protein (MAP) kinases, ERK1 and ERK2, that persisted for at least 2 hr. This extracellular signal-regulated protein kinase (ERK) activation was inhibited successfully by the MEK1 inhibitor PD98059, but not by the estrogen receptor (ER) antagonist ICI 182,780, and did not appear to result from estradiol-induced activation of trk. Furthermore, we also found that estradiol elicited an increase in B-Raf kinase activity. The latter and subsequent downstream events leading to ERK activation may be a consequence of our documentation of a multimeric complex consisting of, at least, the ER, hsp90, and B-Raf. These novel findings provide an alternative mechanism for some of the estrogen actions in the developing CNS and could explain not only some of the very rapid effects of estrogen but also the ability of estrogen and neurotrophins to regulate the same broad array of cytoskeletal and growth-associated genes involved in neurite growth and differentiation.

Geranoyl-CoA carboxylase: a novel biotin-containing enzyme in plants

Geranoyl-CoA carboxylase (EC 6.4.1.4) is a biotin-containing enzyme previously described in two genera of bacteria. Here we report the presence of geranoyl-CoA carboxylase in kingdom Plantae. Geranoyl-CoA carboxylase was purified 180-fold from maize leaves. The enzyme has a biotin-containing subunit of 122 kDa. The pH optimum for activity is 8.3. The apparent Km values for the substrates geranoyl-CoA, bicarbonate, and ATP are 64 +/- 5 microM, 0. 58 +/- 0.04 mM, and 8.4 +/- 0.4 microM, respectively. Subcellular fractionations indicate that geranoyl-CoA carboxylase is located in plastids. Geranoyl-CoA carboxylase activity is ubiquitous in organs of monocots and dicots and varies with development. We postulate that geranoyl-CoA carboxylase plays an important role in isoprenoid catabolism in plants, in a pathway analogous to that shown in Psuedomonas sp. In plants, this catabolic pathway would require the interaction of at least three subcellular compartments (plastids, microbodies, and mitochondria) and two biotin-containing enzymes, geranoyl-CoA carboxylase and 3-methylcrotonyl-CoA carboxylase.

Domain identification by clustering sequence alignments

MOTIVATION

As sequence databases grow rapidly, results from sequence comparison searches using fast search methods such as BLAST and FASTA tend to be long and difficult to digest.

RESULTS

In this paper, we present a new method to extract domain information from sequence comparison searches by clustering the resulting alignments according to their similarity to the query sequence. Efficient tree structures and algorithms are used to organize the alignment data such that structurally conserved elements can be easily identified. The hierarchical nature of the data structures used and the flexible X-Window-based interface provide an efficient and intuitive means to explore the alignment data at different levels so that the common domains, as well as distantly related features, can be explored.

AVAILABILITY

The clustering program is available by anonymous ftp at: ftp.embl-ebi.ac.uk under directory /pub/software/unix, file: clustering.tar.Z.

The effects of Radix Ginseng rubra on cAMP of experimental ischemic myocardium in rats

The model of SD rats ligated at the proximate left anterior descend (LAD) of coronary was used. The number and dissociation constant of beta receptor were studied by using receptor autoradiography to observe the changes in beta receptor and the effects of Radix Ginseng Rubra on cAMP in experimental ischemic myocardium. The result showed that the number of binding site in simple ligation group (Bmax = 0.279) was obviously higher than that in sham operation group (Bmax = 0.093) and the dissociation constant of simple ligation group (Kd = 12. 431) was higher than that of sham operation group (kd = 1.319). There was a significant difference between the two groups (P < 0.05). It proved that the number of beta receptor was increased and the activity was elevated in myocardial cell membranes after ligation of LAD. The myocardial cAMP level in simple ligation group [(1293.96 +/- 519.36) x 10(-3) nmol/g] was much higher than that in sham operation group [(774.44 +/- 210.55) x 10(-3) nmol/g]; but the level of cAMP in ligation group after receiving Radix Ginseng Rubra treatment (805.02 +/- 362.48 pm/g) was obviously lower than that in simple ligation group (P < 0.01), which was close to the result of sham operation. The results indicated that Radix Ginseng Rubra could decrease the cAMP level in ischemic myocardium.

Batch fermentation and optimization of media for Bacillus thuringiensis

The composition of No. II medium obtained with shaking cultivation contained three factors: nitrogen source, carbon source, and inorganic salts. The relationship between component factors (x(i)) of the media and spore numbers (y) of Bacillus thuringiensis (Bt) was demonstrated by the orthogonal-rotation-combination test. A response surface equation was formed as follows: y = 384 - 7.245x1 + 11.705x2 + 15.475x3 + 14.039x1(2) + 41.831x2(2) - 79.49x3(2) - 35.375x1x2 - 3.375x1x3 - 106.625x2x3. The results showed that this method is simple, practical, and rapid enough for selecting fermentation media for Bt. In addition, the whole course of batch fermentation was also investigated.

Saikosaponin b2 induces differentiation without growth inhibition in cultured B16 melanoma cells

Treatment with 5 microM of saikosaponin (SS) b2 for 30 days was found to induce differentiation of B16 melanoma cells, with potentiation of expressions of melanogenesis and tyrosinase. To explore the mechanism of this effect, we observed the cell growth, cell cycle and morphology, and found that SSb2 did not affect any of these parameters. That is, SSb2 induced the differentiation of B16 melanoma cells without growth inhibition or cytotoxicity under conditions of low dose and long-term treatment. Phorbol ester, a protein kinase C (PKC) activator, markedly inhibited the expressions of melanogenesis and tyrosinase in both the control B16 melanoma cells and the long-term treated B16 melanoma cells. Down-regulation of the PKC activity may be involved in the effects of SSb2.

Diarylsulfonylureas--a new class of antitumor agents

Diarylsulfonylureas (DSU) represent a new class of antitumor agents. DSU exhibit an exceptionally broad spectrum of activity against solid tumors. They show different toxicity to conventional anticancer agents and exhibit no cross-resistance with existing anticancer agents. In particular they have an unknown, but unique, potentially novel mechanism of action. Sulofenur is the first DSU to progress to clinical evaluation. The dose-limiting toxicity in humans is anemia and methemoglobinemia. Recently, DSU with novel structural features have also been reported to exhibit potent antitumor activity, demonstrating structural diversity of DSU antitumor agents.

[The development of an intelligent four-channel aggregometer]

The paper introduces the hardware and software design of the instrument. We use 89C52 single-chip computer as the microprocessor to control the amplifier, AD and DA conversion chip to realize the sampling, data process, printout and supervision. The final result is printed out in form of data and aggregation curve from PP40 plotter.

[Multiple subpial transection in surgical treatment of intractable epilepsy]

OBJECTIVE

To increase the effect of epilepsy surgery, we use multiple subpial transection (MST) clinically on the basis of experimental study.

METHOD

We analyzed the seizure type and course of 116 intractable epilepsy patients treated with MST and surgical technique were modified.

RESULT

100 patients were followed up for 1 to 5 years. Complete control of seizure was obtained in 62 patients (62%), significant reduction (over 75%) in 20 (20%), reduction (over 50%) in 12 (12%), and no change in 6 (6%). The total effective rate was 94%, and the significant effective rate was 82%. No functional defect was found in any patients.

CONCLUSION

MST is a effective in surgical treatment of intractable epilepsy and can replace conventional methods. Combined bilateral frontal lobe MST and anterior callosotomy is a good way to treat intractable generalized epilepsy.

Chemical requirements for inhibition of gap junction communication by the biologically active lipid oleamide

Oleamide is an endogenous fatty acid primary amide that possesses sleep-inducing properties in animals and has been shown to effect serotonergic systems and block gap junction communication in a structurally specific manner. Herein, the structural features of oleamide required for inhibition of the gap junction-mediated chemical and electrical transmission in rat glial cells are defined. The effective inhibitors fall into two classes of fatty acid primary amides of which oleamide and arachidonamide are the prototypical members. Of these two, oleamide constitutes the most effective, and its structural requirements for inhibition of the gap junction are well defined. It requires a chain length of 16-24 carbons of which 16-18 carbons appears optimal, a polarized terminal carbonyl group capable of accepting but not necessarily donating a hydrogen bond, a Delta9 cis double bond, and a hydrophobic methyl terminus. Within these constraints, a range of modifications are possible, many of which may be expected to improve in vivo properties. A select set of agents has been identified that serves both as oleamide agonists and as inhibitors of fatty acid amide hydrolase, which is responsible for the rapid inactivation of oleamide.