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PubMed1989

Effects of mutagenic and non-mutagenic aniline derivatives on rat liver drug-metabolizing enzymes.

1. The effect of 4,4'-methylene bis(2-chloroaniline) (MOCA), 4,4'-methylene dianiline (MDA) and 4,4'-sulphonyldianiline (Dapsone) in vivo on xenobiotic biotransformation in male rat liver was studied. 2. Treatment with MOCA or MDA but not Dapsone caused a dose-dependent increase in ethoxyresorufin O-deethylase activity and a concomitant decrease in aldrin epoxidase activity in male rats. 3. Treatment with MOCA or MDA resulted in dose-dependent increases in ethoxycoumarin O-deethylation and epoxide hydrolation, while only MOCA induced cytosolic glutathione S-transferase activity. 4. Treatment with Dapsone resulted in no changes in xenobiotic biotransformation except for the induction of aniline hydroxylation. 5. The results are consistent with the contention that there is a relationship between carcinogenic chemicals and particular alterations in the activities of biotransformation enzymes.

7-Alkoxycoumarin O-Dealkylase↗

PubMed1990

[Comparative ability of three aniline derivatives to alter biotransformation enzymes in rat liver].

The effect of 4,4'-methylene bis (2-chloroaniline) (MOCA), 4,4'-methylene dianiline (MDA) and 4,4'-sulfonyl dianiline (Dapsone) on xenobiotic biotransformation in vivo was studied in male rat liver. Treatment with MOCA and MDA caused a dose dependent increase in ethoxyresorufin O-deethylase activity and concomitant decrease in aldrin epoxidase activity. Treatment with MOCA and MDA also resulted in increases in ethoxycoumarin O-deethylation and epoxide hydrolation while only MOCA induced cytosolic glutathione S-transferase activity. Treatment with Dapsone resulted in no changes in xenobiotic biotransformation except for the induction of aniline hydroxylation. The results are consistent with the contention that there is a relationship between carcinogenic chemicals and particular alteration in the activities of biotransformation enzymes.

Aniline Compounds↗

PubMed2000

Three-dimensional organization of retroviral capsid proteins on a lipid monolayer.

We have used a method for the two-dimensional crystallization of retroviral structural proteins to obtain a three-dimensional structure of negatively stained, membrane-bound, histidine-tagged Moloney murine leukemia virus (M-MuLV) capsid protein (his-MoCA) arrays. Tilted and untilted micrographs from crystals formed by purified his-MoCA proteins incubated beneath lipid monolayers containing nickel-chelating lipids were used in 3D reconstructions. The 2D crystals had unit cell dimensions of a=72.6 A, b=72.5 A and gamma=119.5 degrees, but appeared to have no intrinsic symmetry (p1) in 3D, in contrast to the trigonal or hexagonal appearance of their 2D projections. Membrane-bound his-MoCA proteins showed a strand-like organization, apparently with dimer building blocks. Membrane-proximal regions, or putative N-terminal domains (NTDs), dimerized with different partners than the membrane-distal putative C-terminal domains (CTDs). Evidence also suggests that CTDs can adopt alternate orientations relative to their NTDs, forming interstrand connections. Our results are consistent with helical-spiral models for retrovirus particle assembly, but are not easily reconcilable with icosahedral models.

Capsid↗

PubMed2026

Polygenic risk score for neurodevelopmental disorders and cognitive impairment at long-term follow-up of first-episode psychosis.

BACKGROUND: One of the most outstanding contributions to the understanding of the etiopathogenesis of schizophrenia spectrum disorders (SSD) was the neurodevelopmental hypothesis. SSD and neurodevelopmental disorders (NDD) share pathogenetic mechanisms and overlapping clinical and cognitive impairment features. METHODS: We investigated whether polygenic risk scores (PRSs) for NDD are associated with cognitive performance in patients with first-episode psychosis (FEP). The sample comprised 127 patients with FEP who were followed up for a mean of 20.9 years. Cognitive examination was performed using the MoCA test at follow-up. Pearson coefficient correlations and multiple regression analyses were performed to examine the contribution of the three PRSs for rare neurodevelopmental conditions (PRSNDD), attention-deficit hyperactivity disorder (PRSADHD) and autism spectrum disorder (PRSASD) to cognitive impairment after allowing for the effect of covariates. Furthermore, we examined the interconnections between the PRS for NDD and cognitive impairment using network analysis (NA), including core premorbid variables. RESULTS: PRSNDD showed significant associations with impairment on visuospatial/executive, attention, and language MoCA subtests, after allowing for the influence of covariates. PRSNDD and PRSADHD, but not PRSASD, were significantly associated with worse performance on the total MoCA score. Moreover, in the network analysis, the relationships between PRSs for NDD and cognitive impairment were highly interconnected with premorbid variables and PRSs for schizophrenia and educational attainment. CONCLUSIONS: These results provide evidence for a possible direct genetic effect on cognitive performance for the PRS of common genetic variations related to neurodevelopment and attention deficit hyperactivity disorder in patients with FEP.

Cognitive impairment↗

PubMed1993

Characterization of a "mobilization cassette" in transposon Tn4399 from Bacteroides fragilis.

Derivatives of nonconjugal plasmids that carry Tn4399, a transposon isolated from Bacteroides fragilis, can be mobilized for transfer by the broad-host-range IncP plasmids pRK231 or R751 in Escherichia coli. To characterize regions of Tn4399 involved in mobilization, we have isolated and analyzed subcloned fragments of Tn4399 in E. coli, as well as mutations within the element. We have identified a "mobilization cassette" within a 2.8-kb region of Tn4399 which, when cloned into mobilization-deficient plasmids, allows these plasmids to be mobilized in trans by the IncP plasmids pRK231 and R751. The 2.8-kb region has been sequenced, and several open reading frames have been identified. Mutants defective in two genes, designated mocA and mocB, coding for deduced products of 36.4 and 16.4 kDa, respectively, cannot be mobilized by either IncP plasmid; these mutants can be complemented in the presence of the respective wild-type genes in trans. This suggests that the putative MocA and MocB proteins have a role in the mobilization process. The 36.4-kDa MocA protein contains a 14-amino-acid sequence which is closely related to a highly conserved motif within DNA relaxases encoded by a wide variety of conjugal or mobilizable plasmids. Subcloning experiments also lead to the localization of an oriT region within a 199-bp fragment, internal to the mobilization cassette.

Amino Acid Sequence↗

PubMed1995

Requirements for strand- and site-specific cleavage within the oriT region of Tn4399, a mobilizing transposon from Bacteroides fragilis.

Replicons that contain Tn4399, a conjugal mobilizing transposon isolated from Bacteroides fragilis, can be mobilized in the presence of broad-host-range IncP plasmids RP4 and R751 in Escherichia coli to B. fragilis or E. coli recipients (C. G. Murphy and M. H. Malamy, J. Bacteriol. 175:5814-5823, 1993). To identify the initial DNA processing events involved in Tn4399-mediated mobilization in E. coli, plasmid DNA from pCGM328 (a pUC7 vector that contains the mobilization region of Tn4399) was isolated from donor cells following the release of plasmid DNA from the relaxation complex. Site- and strand-specific cleavage within the oriT region of Tn4399 was detected by denaturing gel electrophoresis and Southern hybridization analysis of this DNA in the presence or absence of IncP plasmids. Mutations in either mocA or mocB, two genes which are encoded by Tn4399 and are required for mobilization, significantly decrease the amount of specifically nicked DNA detected. These results suggest roles for the MocA and MocB gene products in specific processing of Tn4399-containing plasmid DNA prior to mobilization. By isolation of the nicked strand and primer extension of this template, we mapped the precise 5' end of the single-stranded cleavage reaction. The nucleotide position of nicTn4399 is adjacent to two sets of inverted repeats, a genetic arrangement similar to those of previously characterized oriT regions. Two site-directed mutations which remove nicTn4399 (oriT delta 1 and oriT delta 2) cannot be mobilized to recipients when they are present in trans along with functional MocA and MocB proteins and an IncP mobilizing plasmid; they are cis-dominant loss-of-function mutations.

Bacterial Proteins↗

PubMed1995

Alterations of histone phosphorylation in rat spleen cells after treatment with the aromatic amine, 4,4'-methylene-bis(2-chloroaniline).

Alterations of the phosphorylation pattern of histones by the carcinogen, 4,4'-methylene-bis(2-chloroaniline) (MOCA) were investigated using rodent spleen cells. Spleen cells were isolated from Sprague-Dawley rats and treated with either 5, 10, 25, or 50 microM MOCA or acetone vehicle controls for 1, 2, 4, or 8 hours. Cells were incubated with 32P-phosphoric acid, and histones from these cells were fractionated utilizing two-dimensional polyacrylamide gel electrophoresis. Marked stimulation of histone phosphorylation was observed with the 10 microM MOCA treatment. A transient decrease in histone phosphorylation was observed at the 1 and 2 hour time points followed by a marked stimulation at 4 hours.

Animals↗

PubMed2026

Dual Transcranial Direct Current Stimulation Modulates Hierarchical Functional Network Organization in Post-Stroke Cognitive Impairment: A Randomized Controlled Trial.

OBJECTIVE: To evaluate the clinical efficacy of dual transcranial direct current stimulation (tDCS) in patients with post-stroke cognitive impairment (PSCI) and to explore the effects on the hierarchical organization of functional brain networks, ranging from regional synchronization to inter-regional connectivity and global network topology. METHODS: In this randomized, double-blind, sham-controlled trial, 74 PSCI patients received conventional therapy alongside either active dual-tDCS (n = 38) or sham stimulation (n = 36). Active tDCS targeted the dorsolateral prefrontal cortex (DLPFC) via anodal-left/cathodal-right nodes (2.0 mA, 20 min/day, 20 sessions). The primary outcome was the Montreal Cognitive Assessment (MoCA). Secondary outcomes included the Mini-Mental Status Examination (MMSE), Stroop Test (ST), Trail Making Test (TMT), Wechsler Memory Scale (WMS), and Barthel Index (BI). A subgroup of 36 participants (18 per group) underwent resting-state functional magnetic resonance imaging (rs-fMRI) to analyze regional homogeneity (ReHo), functional connectivity (FC), and network topology. Partial correlations assessed the association between neuroimaging alterations and clinical improvements. RESULTS: The tDCS group showed significantly greater improvements in MoCA scores (tDCS: 5.74 ± 2.76 vs. sham: 2.69 ± 2.69; t = 4.799, p < 0.001) as well as in attention and memory domains compared to the sham group. The rs-fMRI changes included increased ReHo in the right middle temporal gyrus (MTG) and the left inferior frontal gyrus (IFG), and reduced FC between the right MTG-left superior frontal gyrus and left IFG-cerebellum (p < 0.05, FWE-corrected). Additionally, small-worldness and global efficiency increased (p < 0.05) with these alterations correlating with clinical recovery. Adverse events were rare and self-limiting. CONCLUSION: Dual-tDCS over bilateral DLPFC safely improves cognitive recovery in PSCI. These clinical gains are associated with rs-fMRI alterations, specifically in regional synchronization, inter-regional connectivity, and global topology, which suggest a potential biomarker for monitoring tDCS efficacy, offering a rationale for precision neuromodulation in stroke rehabilitation.

Humans↗

PubMed2026

Efficacy and safety of add-on topiramate vs. metformin on cardiometabolic profile in patients of schizophrenia on atypical antipsychotics with metabolic syndrome: an active-controlled, rater-blinded, parallel-design randomized controlled trial.

BACKGROUND: Metabolic syndrome is common among patients with schizophrenia, but current treatment options are limited, with metformin being the most studied. While placebo-controlled studies suggest potential benefits of topiramate, comparative efficacy and safety data are lacking. This study aimed to compare the efficacy and safety of topiramate versus metformin for treating metabolic syndrome and reducing cardiovascular risks among patients with schizophrenia. METHODS: A randomised, open-label, parallel-group clinical trial was conducted on 60 patients of schizophrenia with metabolic syndrome, randomised equally to receive either topiramate (50 mg/day) or metformin (1000 mg/day) for eight weeks. Primary outcome was cardiovascular risk score (QRISK3), and secondary outcomes were LDL∶HDL ratio, insulin resistance (HOMA-IR), positive and negative syndrome scale (PANSS), Montreal Cognitive Assessment (MoCA) and clinical global impression-Schizophrenia scale (CGI-SCH) scores. RESULTS: Over the study period, QRISK3 scores improved significantly in both groups [topiramate: MD = 0.61 (0.02 to 1.21), p = 0.04; metformin: MD = 0.45 (0.07 to 0.83), p = 0.02], with no significant between-group difference in unadjusted analysis (p = 0.648). However, ANCOVA adjusting for baseline QRISK3 revealed a significantly greater improvement in the topiramate group (β = -0.324, p = 0.043). Metformin showed significant within-group improvements in LDL: HDL ratio and HOMA-IR; however, ANCOVA adjusting for baseline HOMA-IR showed the between-group difference remained non-significant (β = -1.209, p = 0.078). Both groups showed significant improvements in PANSS and CGI-SCH scores, with no significant between-group differences in MoCA scores. A moderate correlation between the QRISK3 change, the PANSS change, and the CGI-SCH-I scores was observed in the topiramate group and the total population. Regression analysis identified PANSS change as a predictor of QRISK3 improvement. CONCLUSION: Topiramate demonstrated comparable, and on adjusted analysis superior, cardiovascular risk reduction compared to metformin, supporting its use as a viable alternative in the management of metabolic syndrome in patients with schizophrenia on atypical antipsychotics, particularly where metformin is contraindicated.

Humans↗

PubMed1989

Genotoxicity of aniline derivatives in various short-term tests.

Various substituted aniline derivatives were tested for genotoxicity in several short-term tests in order to examine the hypothesis that a substitution at both ortho positions (2,6-disubstitution) could prevent genotoxicity due to steric hindrance of an enzymatic activation to electrophilic intermediates. In the Salmonella/microsome assay, 2,6-dialkylsubstituted anilines and 2,4,6-trimethylaniline (2,4,6-TMA) were weakly mutagenic in strain TA100 when 20% S9 mix was used, although effects were small compared to those of 2,4-dimethylaniline and 2,4,5-trimethylaniline (2,4,5-TMA). In Drosophila melanogaster, however, 2,4,6-TMA and 2,4,6-trichloroaniline (TCA) were mutagenic in the wing spot test at 2-3 times lower doses than 2,4,5-TMA. In the 6-thioguanine resistance test in cultured fibroblasts, 2,4,6-TMA was again mutagenic at lower doses than 2,4,5-TMA. Two methylene-bis-aniline derivatives were also tested with the above methods: 4,4'-methylene-bis-(2-chloroaniline) (MOCA) was moderately genotoxic in all 3 test systems whereas 4,4'-methylene-bis-(2-ethyl-6-methylaniline) (MMEA) showed no genotoxicity at all. DNA binding studies in rats, however, revealed that both MOCA and MMEA produced DNA adducts in the liver at levels typically found for moderately strong genotoxic carcinogens. These results indicate that the predictive value of the in vitro test systems and particularly the Salmonella/microsome assay is inadequate to detect genotoxicity in aromatic amines. Genotoxicity seems to be a general property of aniline derivatives and does not seem to be greatly influenced by substitution at both ortho positions.

Aniline Compounds↗

PubMed2004

Two-dimensional electrophoretic protein profile analysis following exposure of human uroepithelial cells to occupational bladder carcinogens.

Protein biomarkers to occupational carcinogens were investigated using a transformable human uroepithelial cell system, SV-HUC.PC. SV-HUC.PC was treated with N-hydroxy-4,4'-methylene bis (2-chloroaniline) (N-OH-MOCA) or N-hydroxy-4 aminobiphenyl (N-OH-ABP). Two-dimensional gel electrophoresis of cell lysates compared protein changes across treatments. Increasing N-OH-MOCA resulted in a dose-related increase in protein spots altered. Comparing cell profiles treated with either carcinogen revealed alterations in the expression of nine proteins, identified using the TagIdent database. These demonstrated isoelectric point shift (1) or quantity change (8). Our investigation may be useful in identifying biomarkers of effects of exposure to bladder carcinogens.

Biomarkers↗

PubMed2006

Correlation between induction of DNA fragmentation in lung cells from rats and humans and carcinogenic activity.

Six chemicals, known to induce lung tumors in rats, were examined for their ability to induce DNA fragmentation in primary cultures of rat and human lung cells, and in the lung of intact rats. Significant dose-dependent increases in the frequency of DNA single-strand breaks and alkali-labile sites, as measured by the single-cell gel electrophoresis (Comet) assay, were obtained in primary lung cells from male rats with the following, minimally toxic, concentrations of the six test compounds: N-nitrosodimethylamine (NDMA; 2.5-10 mM), hydrazine (HZ; 0.5-4 mM), cadmium sulfate (CD; 31.2 and 62.5 μM), 4,4'-methylene bis (2-chloroaniline) (MOCA; 31.2-125 μM), isobutyl nitrite (IBN; 7.8-31.2 μM) and tetranitromethane (TNM; 1.9-15.6 μM). Similar degrees of DNA fragmentation were obtained in primary human lung cells; however, due to inter-donor differences, the minimum effective concentrations were in some donors lower and in others higher than in rats, and IBN induced DNA damage only in one of three donors. The DNA-damaging potency of HZ was higher in rats than in humans, and the opposite was true for MOCA. In agreement with these findings, statistically significant increases in the average frequency of DNA breaks were obtained in the lung of rats given a single oral dose (1/2 LD50) of the six test compounds. These findings give evidence that genotoxic lung carcinogens may be identified by use of the DNA fragmentation/Comet assay on rat lung cells as targets cells, and show that the six compounds tested produce in primary cultures of lung cells from human donors DNA-damaging effects substantially similar to those observed in rats.

Adenocarcinoma↗

PubMed2006

FTIR spectroscopic characterization of polyurethane-urea model hard segments (PUUMHS) based on three diamine chain extenders.

Six polyurethane-urea model hard segments (PUUMHS) were prepared by a solution method based, respectively, on two isocyanates: 4,4'-methylene-diphenyl-diisocyanate (MDI), 4,4'-methylene-dicyclohexyl diisocyanate (HMDI) and three amine chain extenders: ethylene diamine (EDA), methylene-bis-ortho-chloroaniline (MOCA), 2,4-diamino-3,5-dimethylsuphylchlorobenzene (DDSCB). FTIR was used to study their spectroscopic characterization. The main FTIR bands of the six samples were assigned and compared. It was found that most of N-H and C=O are H-bonded in these PUUMHS. However, the N-H in three MDI based PUUMHS is all in the stronger H-bond state than that in their corresponding HMDI based while the C=O in three HMDI based PUUMHS is all in the stronger H-bond state than that in their corresponding MDI based, respectively. In addition, the order of the H-bond strength in HMDI based PUUMHS is MOCA, DDSCB and EDA whether according to nuN-H or nuC=O band wavenumbers, which is, however, different from that in MDI based PUUMHS. Moreover, the HMDI based PUUMHS shows obvious double amide III bands while the MDI based has only prominent one. The results are discussed according mainly to the different characteristics of the three chain extenders as well as the structure difference between MDI and HMDI.

Diamines↗

PubMed2001

Carcinogen substrate specificity of human COX-1 and COX-2.

The activation of carcinogenic aromatic and heterocyclic amines and benzo[a]pyrene-7,8-diol to intracellular electrophiles by prostaglandin H synthase (COX) is well documented for ovine sources of this enzyme. Here, the arachidonic acid-dependent activation of substrates by human (h)COX-1 and-2 is examined, utilizing recombinant enzymes. The COX-dependent activation of benzidine (BZ), 4-aminobiphenyl, (+)benzo[a]pyrene-7,8-diol, (+)benzo[a]pyrene-7,8-diol, 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), 2-amino-3-methylimidazo [4,5-f]quinoline (IQ), 2-amino-1-methyl-6-phenylimidazo [4,5-b] pyridine (PhIP), and 4,4'-methylenebis(2-chloroaniline) (MOCA) is assessed by means of COX-catalyzed, covalent DNA binding. The hCOX isozymes activated all substrates tested, activation varied from barely detectable for IQ (0.76 and 1.52 pmol bound/mg DNA for COX-1 and -2, respectively) to a high of 65 and 117 pmol bound/mg DNA for COX-1 and -2, respectively, for the activation of MOCA. BZ, which is an excellent peroxidase substrate, did not exhibit high DNA binding levels in hCOX assays and this phenomenon was found to be due to high levels of binding to protein, which effectively competed with the DNA for binding in the assay. The demonstrated ability of the COX enzymes to activate a variety of environmental and dietary carcinogens indicates a potential role for COX in the activation pathway of aromatic and heterocyclic amines and polycyclic hydrocarbons at extra-hepatic sites during early or late stages of carcinogenesis.

Animals↗

PubMed1998

Occupational applications of a human cancer research model.

Many bladder cancers are indolent, and since there are no biomarkers to predict progression, the prognosis is problematic. Utilizing an in vitro/in vivo human uroepithelial cell (SV-HUC.PC) transformation system, we investigated several molecular events occurring along the continuum of exposure to disease outcome as potential biomarkers for occupational carcinogenesis. The model also served to generate information on the occupational carcinogenicity of N-hydroxy-4,4'-methylene bis(2-chloroaniline) [N-OH-MOCA]. Two of 14 groups of SV-HUC.PC treated with various concentrations of N-OH-MOCA formed carcinomas in athymic nude mice. Each of the biomarkers investigated demonstrated potential for interventions/prevention applications of occupational bladder cancers but will require validation and further evaluation. Those investigated displaying potential occupational utility included the induction of ornithine decarboxylase (ODC), DNA adducts, and altered proteins, as detected on HUC two-dimensional polyacrylamide gel electrophoresis protein maps.

Animals↗

PubMed1997

Characterization of 1-hydroxypyrene as a novel marker substrate of 3-methylcholanthrene-inducible phenol UDP-glucuronosyltransferase(s).

Rats were treated with acetone, pyrazole, phenobarbital, 4,4'-methylenebis-(2-chloroaniline) (MOCA), 3-methylcholanthrene, creosote oil, or a mixture of polychlorinated biphenyls (Aroclor 1254) to study the inducibility and enzyme kinetics of UDP-glucuronosyltransferases towards 1-hydroxypyrene, which is a human metabolite and a urinary biomarker of exposure to pyrene. The rate of 1-hydroxypyrene glucuronidation was analyzed in rat liver microsomes by a fluorometric HPLC assay of the formed glucuronide. The apparent K(m) and Vmax values in untreated controls (K(m) = 0.27 mM; Vmax = 31 nmol/min./mg protein) did not differ markedly from those in rats treated with acetone, pyrazole or phenobarbital, whereas the significantly decreased K(m) and increased Vmax values of the rats treated with the carcinogenic chemicals, MOCA (0.11; 51), creosote (0.06; 137), 3-methylcholanthrene (0.07; 141) or the Aroclor-1254 polychlorinated biphenyl (PCB) mixture (0.08; 226), implicated major changes in the hepatic expression of UDP-glucuronosyltransferases. 1-Hydroxypyrene proved to be a high affinity substrate and a sensitive marker of the polycyclic aromatic hydrocarbon (PAH) metabolizing UDP-glucuronosyltransferase(s). Catalytically, the most efficient isoforms were induced in creosote, 3-methylcholanthrene and PCB-treated rats showing Vmax/K(m) ratios which were 22-27 times greater than in untreated controls. Our findings suggest the existence of a 3-methylcholanthrene type inducible and a functionally efficient low-K(m)/ high-Vmax form(s) of UDP-glucuronosyltransferase(s) that detoxify 1-hydroxypyrene and probably other polycyclic aromatic hydrocarbons as well.

Acetone↗

PubMed2005

RANTES and chemotactic activity in synovial fluids from patients with rheumatoid arthritis and osteoarthritis.

A massive accumulation of inflammatory cells in synovial tissues is a major pathological feature of rheumatoid arthritis (RA). Neutrophiles dominate synovial fluid while rheumatoid synovium is infiltrated with mononuclear cells. Mechanisms regulating influx of particular subpopulations of leukocytes into articular cavity and synovium compartment are not completely defined. An increasing amount of data supports a crucial role of a C-C chemokine RANTES in the RA pathogenesis. Our objective is to evaluate chemotactic activity for neutrophils (NCA), lymphocytes (LCA), and monocytes (MoCA) in SFs obtained from patients with RA and osteoarthritis (OA). We also aimed to characterise the relation between chemotactic activity, RANTES, and percentage distribution of leukocytes in SF. SFs from 11 patients with RA and 6 with OA were included in the study. Modified microchamber Boyden method was employed to assess chemotactic activity. Cytological and biochemical analysis of SF was performed. RANTES was measured with ELISA. Rheumatoid SFs were rich in cells with predominance of neutrophiles while osteoarthritic fluids were lymphocytic. RA SFs were also characterised by increased lactoferrin level. Both NCA and LCA were higher in SF from patients with RA (62 +/- 12 and 24 +/- 6 cells/HPF, resp) as compared to patients with OA (23 +/- 6; P < .05 and 6 +/- 2 cells/HPF; P < 0.05). The chemoattractive effect of RA SF was more pronounced on neutrophiles than on lymphocytes. RA SF expressed high RANTES levels (145+/- 36 pg/mL), while OA SF was characterised by only trace amount of this chemokine (2 +/- 1 pg/mL). We found positive correlation of RANTES with chemotactic activity for mononuclear cells (LCA + MoCA; R = 0.61; P < .05). Surprisingly, RANTES correlated also positively with neutrophiles number (R = 0.77; P < 0.001). Rheumatoid SF possesses strong chemotactic potency for leukocytes. RANTES is overexpressed in RA SF and is a potential mediator influencing intensity and composition of cellular infiltration in joints affected with inflammatory arthritis.

Aged↗

PubMed1991

Purification and characterization of human liver microsomal cytochrome P-450 2A6.

Cytochrome P-450 (P-450) 2A6 was purified by chromatography of human liver microsomes. The final preparation was electrophoretically homogeneous and contained 16 nmol of P-450/mg of protein. The amino-terminal amino acid sequence of the protein (first 13 residues) matched that of the reported cDNA exactly. The UV-visible spectrum indicated that the isolated hemoprotein was in the low-spin form. The protein was recognized by rabbit antibodies raised against rat P-450 2A1, and a rabbit antiserum against the P-450 2A6 preparation was also prepared. With these antibodies, it was estimated that P-450 2A6 accounted for a maximum of 1% of the total P-450 present in the human liver microsomes; the level varied greater than 100-fold among the 20 samples examined. Purified P-450 2A6 catalyzed coumarin 7-hydroxylation and 7-ethoxycoumarin O-deethylation at rates similar to those measured in the human liver sample used to prepare P-450 2A6, and these two microsomal activities were strongly inhibited by the antibodies. The purified P-450 2A6 enzyme also catalyzed low levels of 4,4'-methylene-bis(2-chloroaniline) (MOCA) N-oxidation and activation of aflatoxin B1, 6-aminochrysene, 2-amino-3-methylimidazo[4,5-f]quinoline, and 2-amino-3,5-dimethylimidazo [4,5-f]quinoline to genotoxic products; the antibody inhibited the activity of purified P-450 2A6 towards aflatoxin B1 and 6-aminochrysene but did not inhibit these reactions in human liver microsomes (MOCA N-oxidation was inhibited approximately 20%). Human P-450 2A6 did not catalyze testosterone 7 alpha-hydroxylation, a characteristic activity of the related rat P-450 2A1 protein. These results emphasize the need to characterize individual P-450 enzymes in order to understand their functions in the context of more complex systems.

7-Alkoxycoumarin O-Dealkylase↗