451
|
Abstract
BACKGROUND The reference strains NCTC11637 and NCTC11638 were among the very first Helicobacters ever cultured and have been distributed through national reference culture collections to researchers throughout the world. Because H. pylori is an extremely diverse species, such reference strains are invaluable as universal standards, provided that they are identified correctly. MATERIALS AND METHODS H. pylori strains (previously called "NCTC11637") from three different sources and NCTC11638 were fingerprinted by the arbitrarily primed polymerase chain reaction (PCR) (also known as random amplified polymorphic DNA, or RAPD) method and further were characterized by NotI digestion and pulsed field gel electrophoresis of total genomic DNA (NotI-PFGE) and by restriction of PCR-amplified ureCD and flaA gene segments. RESULTS RAPD tests of two "NCTC11637" strains from different sources (CCUG17874, UA1178) indicated that they were closely related or identical to NCTC11638. Given the diversity of H. pylori strains and the high sensitivity of the RAPD method, close matches in RAPD patterns from independent clinical isolates are not expected. In contrast, the version of "NCTC11637" from the American Type Culture Collection (ATCC43504) did not match NCTC11638 in RAPD fingerprint. Concordant results were obtained by NotI-PFGE and by restriction of PCR amplified gene segments. CONCLUSIONS Two unrelated versions of the reference (type) H. pylori strain NCTC11637 are in general circulation and are distinguished easily by DNA fingerprinting. One matches another reference strain, NCTC11638, whereas the other is distinct from it, as expected of independent clinical isolates. Knowing which "NCTC11637" reference strain one has could be important, especially because H. pylori strains probably are diverse in phenotypic traits that are important for colonization or disease.
Collapse
Affiliation(s)
- N S Akopyants
- Department of Molecular Microbiology, Washington University Medical School, St. Louis, MO 63110, USA
| | | | | | | |
Collapse
|
452
|
Lian HZ, Zhang WB, Miao J, Jiang Q, Mao L, Zong L, Li L, Wu XX, Cheng RM. A study on the stability of bronopol in bronopol lotion by ion-paired reversed-phase high performance liquid chromatography. J Pharm Biomed Anal 1997; 15:667-71. [PMID: 9127279 DOI: 10.1016/s0731-7085(96)01895-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- H Z Lian
- Center of Materials Analysis, Nanjing University, People's Republic of China
| | | | | | | | | | | | | | | | | |
Collapse
|
453
|
Abstract
We developed a fibrin-rich thrombotic focal cerebral ischemic model with reproducible and predictable infarct volume in rats. In male Wistar rats (n = 77), a thrombus was induced at the origin of the middle cerebral artery (MCA) by injection of thrombin via an intraluminal catheter placed in the intracranial segment of the internal carotid artery (ICA). Thrombus induction and consequent ischemic cell damage were examined by histopathological analysis and neurological deficit scoring, and by measuring changes in cerebral blood flow (CBF) using laser-Doppler flowmetery (LDF), perfusion-weighted imaging (PWI), and by diffusion weighted imaging (DWI). Histopathology revealed that a fibrin-rich thrombus localized to the origin of the right MCA. Regional cerebral blood flow (rCBF) in the right parietal cortex was reduced by 34-58% of preinjection levels after injection of thrombin in rats administered 30 U of thrombin (n = 10). Magnetic resonance imaging (MRI) showed a reduction in CBF and a hyperintensity DWI encompassing the territory supplied by the right MCA. The infarct volume in rats administered 80 U of thrombin was 31.29 +/- 12.9% of the contralateral hemisphere at 24 h (n = 13), and 34.7 +/- 16.4% of the contralateral hemisphere at 168 h (n = 6). Rats administered 30 U of thrombin exhibited a hemispheric infarct volume of 34.0 +/- 14.5% (n = 9) at 24 h and 29.7 +/- 13.9% (n = 8) at 168 h. In addition, thrombotic rats (n = 3) treated with recombinant tissue plasminogen activator (rt-PA) (10 mg/kg) 2 h after thrombosis showed that CBF rapidly returned towards preischemic values as measured by PWI. This model of thrombotic ischemia is relevant to thromboembolic stroke in humans and may be useful in documenting the safety and efficacy of thrombolytic intervention as well as for investigating therapies complementary to antithrombotic therapy.
Collapse
Affiliation(s)
- Z Zhang
- Department of Neurology, Henry Ford Health Science Center, Detroit, Michigan, USA
| | | | | | | | | | | |
Collapse
|
454
|
Jiang Q, Wakerley JB. The milk-ejection reflex in the peri-partum rat: effects of oestradiol and progesterone on basal milk-ejection frequency and the facilitatory response to central oxytocin. J Neuroendocrinol 1997; 9:9-16. [PMID: 9023734 DOI: 10.1046/j.1365-2826.1997.00602.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Experiments were undertaken to examine the effects of ovarian steroids on the functional characteristics of the milk-ejection reflex during late pregnancy. Basal milk-ejection frequency and response to i.c.v. oxytocin (OT) were compared in different experimental groups, using intramammary pressure recordings obtained in suckling tests under urethane anaesthesia. Ovariectomy (OVX) on day 20 of pregnancy significantly (P < 0.05) increased milk-ejection frequency on day 22, compared with sham-OVXed animals. I.c.v. injection of 2.2 ng OT during suckling had no consistent effect on milk ejection in either of these groups. Pretreatment with oestradiol (5 micrograms per day, s.c.) or progesterone (5 mg per day, s.c.) both resulted in a fall in milk-ejection frequency compared to oil-treated OVXed controls. However, whereas oestradiol-treated OVXed rats showed a facilitatory response to i.c.v. OT, with a significant (P < 0.05) increase in milk-ejection frequency in the 20 min period after injection, progesterone-treated OVXed rats showed only a delayed decrease in milk-ejection frequency (significant at P < 0.05 between 20-40 min after injection). Oil-treated OVXed rats showed no significant response to i.c.v. OT at any stage. Electrophysiological recordings from supraoptic OT neurones confirmed that bursting activity was increased by i.c.v. injection of OT in oestradiol-treated, but not progesterone-treated rats. Further experiments with hysterectomized ovariectomized rats indicated that the difference in response to i.c.v. OT in oestradiol- vs progesterone-treated rats was not related to changes in the timing of birth induced steroid treatments. These findings demonstrate the ability of ovarian steroids to alter the characteristics of the milk-ejection reflex in the peri-partum rat. In particular, the rise in oestradiol and fall in progestesterone near term, may contribute to programming of the facilitary response to central OT in preparation for lactation.
Collapse
Affiliation(s)
- Q Jiang
- Department of Anatomy, School of Medical Sciences, University of Bristol, UK
| | | |
Collapse
|
455
|
Abstract
The model legume Lotus japonicus was demonstrated to be amenable to classical and molecular genetic analysis, providing the basis for the genetic dissection of the plant processes underlying nodulation and nitrogen fixation. We have developed an efficient method for the sexual hybridization of L. japonicus and obtained F1 progeny derived from a cross of L. japonicus B-129-S9 Gifu x B-581 Funakura. Over half of the cross-pollinations resulted in fertile hybrid seed, which were confirmed morphologically and by single arbitrary primer DNA amplification polymorphisms using the DAF technique. Molecular and morphological markers segregated in true Mendelian fashion in a F2 population of 100 plants. Several DAF loci were linked using the MAPMAKER software to create the first molecular linkage groups of this model legume. The mapping population was advanced to generate a set of immortal recombinant inbred lines (F6; RILs), useful for sharing plant material fixed genetically at most genomic regions. Morphological loci for waved stem shape (Ssh), dark leaf color (Lco), and short flowering period (Fpe) were inherited as single dominant Mendelian loci. DAF markers were dominant and were detected between Gifu and Funakura at about one per primer, suggesting that the parents are closely related. One polymorphism (270G generated by single octomer primer 8.6m) was linked to a morphological locus controlling leaf coloration. The results demonstrate that (i) Lotus japonicus is amenable to diploid genetic analysis, (ii) morphological and molecular markers segregate in true diploid fashion, (iii) molecular polymorphisms can be obtained at a reasonable frequency between the related Gifu and Funakura lines, and iv) the possibility exists for map-based cloning, marker assisted selection and mapping of symbiotic mutations through a genetic and molecular map.
Collapse
Affiliation(s)
- Q Jiang
- Center for Legume Research, University of Tennessee, Knoxville 37901-1071 USA
| | | |
Collapse
|
456
|
Jiang Q, Chopp M, Zhang ZG, Knight RA, Jacobs M, Windham JP, Peck D, Ewing JR, Welch KM. The temporal evolution of MRI tissue signatures after transient middle cerebral artery occlusion in rat. J Neurol Sci 1997; 145:15-23. [PMID: 9073024 DOI: 10.1016/s0022-510x(96)00286-9] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We have developed a multiparameter magnetic resonance imaging (MRI) cluster analysis model of acute ischemic stroke using T2 relaxation times and the diffusion coefficient of water (ADCw). To test the ability of this model to predict cerebral infarction, male Wistar rats (n = 7) were subjected to 2 h of transient middle cerebral artery (MCA) occlusion, and diffusion and T2 weighted MRI were performed on these rats before, during and up to 7 days after MCA occlusion. MRI tissue signatures, specified by values of ADCw and T2 were assigned to tissue histopathology. Significant correlations were obtained between MRI signatures at different time points and histopathologic measurements of lesion area obtained at 1 week. In addition, we compared the temporal evolution of MRI tissue signatures to a separate population of animals at which histological data were obtained at select times of reperfusion. A significant shift (p < or = 0.05) within signatures reflecting tissue histopathology was demonstrated as the ischemic lesion evolved over time. Our data suggest, that the MRI signatures are associated with the degree of ischemic cell damage. Thus, the tissue signature model may provide a noninvasive means to monitor the evolution of ischemic cell damage and to predict final outcome of ischemic cell damage.
Collapse
Affiliation(s)
- Q Jiang
- Department of Neurology, Henry Ford Health Science Center, Detroit, MI 48201, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
457
|
Abstract
The inability of conventional gel electrophoresis to separate DNA molecules exceeding 50 kb in size led to the development of pulsed-field gel electrophoresis (PFGE) by Schwartz et al, (1)in 1982. He introduced the concept of applying two alternating electric fields (i.e., pulsed-field) to separate DNA molecules greater than 50 kb embedded in an agarose gel matrix. Since then, many instruments based on this principle have been developed. For a discussion of various pulsed-field applications, see review articles by Lai et al. (2) and Crété et al. (3). It was shown that, under the influence of an electric field, a DNA molecule embedded in a gel matrix undergoes reorientation, elongation, and migration along the field toward the anode. When a second field is applied in an alternate direction, the DNA molecule must reorientate, elongate, and migrate along the direction of the new field. Larger DNA molecules will take longer to reorientate than smaller molecules; therefore the larger ones spend less time migrating down the gel than the smaller per pulse time. Consequently, larger DNA molecules will appear near the origin while the smaller molecules will migrate furthest. This principle becomes important when different fragment sizes of DNA are to be separated. PFGE has become an important tool for determining genome sizes, physical mapping of the chromosome, and localization of genes on the chromosome of prokaryotic micro-organisms.
Collapse
Affiliation(s)
- N Chang
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta, Canada
| | | | | |
Collapse
|
458
|
Huang Y, Jiang Q, Voigt JM, Debolt KM, Colby HD. Strain differences in adrenal CYP2D16 expression in guinea pigs. Relationship to xenobiotic metabolism. Biochem Pharmacol 1996; 52:1925-9. [PMID: 8951353 DOI: 10.1016/s0006-2952(96)00665-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Experiments were done to determine the mechanisms responsible for differences in adrenal microsomal xenobiotic metabolism between Strain 13 and English Short-Hair (ESH) guinea pigs. The rates of adrenal xenobiotic metabolism (bufuralol 1'-hydroxylase, benzo[a]pyrene hydroxylase, benzphetamine N-demethylase) were 2-3 times greater in microsomes from the Strain 13 animals. In both strains, xenobiotic-metabolizing activities were far greater in the inner zone (zona reticularis) than in the outer zones (zona fasciculata and zona glomerulosa) of the adrenal cortex. Northern blot analyses of total adrenal RNA with a CYP2D16 cDNA as the probe revealed significantly greater amounts of CYP2D16 mRNA in the Strain 13 guinea pigs. In addition, SDS-PAGE and Western blotting of adrenal microsomes demonstrated higher concentrations of CYP2D16 protein in Strain 13 than in ESH animals. Expression of CYP2D16 was predominantly in the inner zone of the adrenal, coinciding with the major site of xenobiotic metabolism. The results demonstrated higher levels of expression of CYP2D16 in adrenal glands from Strain 13 than from ESH guinea pigs, which may account for the strain differences in adrenal xenobiotic metabolism. Strain 13 guinea pigs should serve as a good experimental model for further studies on the regulation of adrenal CYP2D16.
Collapse
Affiliation(s)
- Y Huang
- Department of Pharmacology and Tøxicology, Philadelphia College of Pharmacy and Science, PA 19104, USA
| | | | | | | | | |
Collapse
|
459
|
Jiang Q, Huang Y, Voigt JM, DeBolt KM, Kominami S, Takemori S, Funae Y, Colby HD. Differential effects of adrenocorticotropin in vivo on cytochromes P4502D16 and P450c17 in the guinea pig adrenal cortex. Endocrinology 1996; 137:4811-6. [PMID: 8895351 DOI: 10.1210/endo.137.11.8895351] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Studies were performed to compare the effects of ACTH treatment in vivo on cytochromes P4502D16 and P450c17 in the guinea pig adrenal cortex. In untreated animals, CYP2D16 protein and messenger RNA (mRNA) expression as well as xenobiotic-metabolizing activities (bufuralol 1'-hydroxylase, benzphetamine N-demethylase, and benzo(a)pyrene hydroxylase) were far greater in the inner (zona reticularis) than the outer (zona fasciculata plus zona glomerulosa) zones of the cortex. ACTH treatment for 3 or 7 days significantly decreased the rates of xenobiotic metabolism in both the inner and outer adrenal zones. Western and Northern blot analyses revealed that adrenal CYP2D16 protein and mRNA concentrations were significantly decreased by ACTH. In contrast to its inhibitory effects on CYP2D16, ACTH treatment increased steroid 17 alpha-hydroxylase activity in the adrenal inner zone, but did not affect outer zone activity. Microsomal CYP17 protein concentrations were not affected by ACTH despite increases in CYP17 mRNA levels in both zones. The results indicate that ACTH causes down-regulation of adrenal CYP2D16, probably at the transcriptional level. Thus, modulation of CYP2D16 by ACTH is opposite that for the steroidogenic P450 isozymes, suggesting unique regulatory mechanisms. In addition, the data suggest that posttranscriptional mechanisms contribute to ACTH regulation of 17 alpha-hydroxylase activity in the guinea pig adrenal cortex.
Collapse
Affiliation(s)
- Q Jiang
- Department of Pharmacology and Toxicology, Philadelphia College of Pharmacy and Science, Pennsylvania 19104, USA
| | | | | | | | | | | | | | | |
Collapse
|
460
|
Jiang Q, Van Rhee AM, Kim J, Yehle S, Wess J, Jacobson KA. Hydrophilic side chains in the third and seventh transmembrane helical domains of human A2A adenosine receptors are required for ligand recognition. Mol Pharmacol 1996; 50:512-21. [PMID: 8794889 PMCID: PMC3418326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Hydrophilic residues of the G protein-coupled human A2A adenosine receptor that are potentially involved in the binding of the ribose moiety of adenosine were targeted for mutagenesis. Residues in a T88QSS91 sequence in the third transmembrane helical domain (TM3) were individually replaced with alanine and other amino acids. Two additional serine residues in TM7 that were previously shown to be involved in ligand binding were mutated to other uncharged, hydrophilic amino acids. The binding affinity of agonists at T88 mutant receptors was greatly diminished, although the receptors were well expressed and bound antagonists similar to the wild-type receptor. Thus, mutations that are specific for diminishing the affinity of ribose-containing ligands (i.e., adenosine agonists) have been identified in both TM3 and TM7. The T88A and T88S mutant receptor fully stimulated adenylyl cyclase, with the dose-response curves to CGS 21680 highly shifted to the right. A Q89A mutant gained affinity for all agonist and antagonist ligands examined in binding and functional assays. Q89 likely plays an indirect role in ligand binding. S90A, S91A, and S277C mutant receptors displayed only moderate changes in ligand affinity. A S281N mutant gained affinity for all adenosine derivatives (agonists), but antagonist affinity was generally diminished, with the exception of a novel tetrahydrobenzothiophenone derivative.
Collapse
Affiliation(s)
- Q Jiang
- Molecular Recognition Section, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
| | | | | | | | | | | |
Collapse
|
461
|
Jiang Q, Zhang S, Yuan H, Liu Z, Zhao G, Brinkmann U. The effect of a combined approach to schistosomiasis control on the transmission of Schistosoma japonicum in Xingzi of Poyang Lake area, China. Southeast Asian J Trop Med Public Health 1996; 27:535-41. [PMID: 9185265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The impact of a combined approach to schistosomiasis control from 1987 to 1989 and mass chemotherapy from 1992 to 1994 was studied in a rural community in Xingzi county in the northwest corner of Poyang Lake in Jiangxi Province, China. Humans, cattle, buffalo and pigs were known potential reservoirs of Schistosoma japonicum. Transmission occurs during water contact on and around seasonally flooded marshes that are used for grazing, the harvesting of grass and fishing. Humans and livestock underwent yearly selective mass chemotherapy, and snails were eliminated through ploughing and compacting of the marshland in the spring of 1988. Transmission was monitored through the determination of annual re-infection rates in samples of the human population, the annual examination of piles of feces from animals and humans in the marshland, the annual collection and examination of intermediate snail hosts, and the exposure to potentially polluted water and subsequent examination of sentinel mice. Schistosomiasis prevalence among humans and animals declined sharply as soon as mass chemotherapy was implemented. Snail density decreased even before mollusc control was started, possibly indicating a high variability of this indicator. The infection rates of snails and sentinel mice reached zero after a single application of mollusc control. The results underline the importance of single infected water buffalo for the transmission of schistosomiasis. Since the impact stopped for two years (1990-1991), the schistosomiasis prevalence rose quickly. Mass chemotherapy was an effective means to curb the prevalence of schistosomiasis in this area, but the effects were only maintained for one or two years in the marsh zone.
Collapse
Affiliation(s)
- Q Jiang
- Shanghai Medical University, People's Republic of China
| | | | | | | | | | | |
Collapse
|
462
|
Jiang Q, Walton NY, Gunawan S, Treiman DM. High-performance liquid chromatographic determination of midazolam in rat brain. J Chromatogr B Biomed Appl 1996; 683:276-80. [PMID: 8891927 DOI: 10.1016/0378-4347(95)00569-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
A high-performance liquid chromatography method for the determination of midazolam in rat brain is described. Midazolam and the internal standard halazepam were extracted with toluene and analyzed isocratically on a reversed-phase column with a mobile phase consisting of methanol, acetonitrile and potassium phosphate buffer. Detection was monitored by ultraviolet absorption at 240 nm. The standard curves were linear over the range of 25-350 ng midazolam per 50 mg brain tissue. The day-to-day coefficient of variation ranged from 1.7 to 6.9%. The limit of quantification was 80 ng/g brain tissue. The method is rapid, simple and reproducible for brain analysis.
Collapse
Affiliation(s)
- Q Jiang
- Neurology Service, Department of Veteran Affairs Medical Center, Los Angeles, CA 90073, USA
| | | | | | | |
Collapse
|
463
|
IJzerman AP, Von Frijtag Drabbe Künzel JK, Kim J, Jiang Q, Jacobson KA. Site-directed mutagenesis of the human adenosine A2A receptor. Critical involvement of Glu13 in agonist recognition. Eur J Pharmacol 1996; 310:269-72. [PMID: 8884226 PMCID: PMC5472059 DOI: 10.1016/0014-2999(96)00495-5] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
A glutamic acid residue in the first transmembrane domain of the human adenosine A2A receptor was mutated to glutamine. Radioligand binding studies on COS-7 cell membranes expressing either the wild-type or the mutant receptor revealed that the affinity of the prototypic agonist CGS21680 (2-[4-[(2-carboxyethyl)phenyl]ethylamino]-5'-N-ethylcarboxamidoadenosine ) for the mutant receptor was 15-fold lower than for the wild-type receptor. This was confirmed in functional studies with intact cells. The EC50 values of CGS21680 for the stimulation of cAMP production differed in a similar way. Antagonists of various chemical structure were equally effective on both mutant and wild-type receptors, thus the mutation selectively diminishes agonist affinity. We propose an indirect perturbation of the binding site, perhaps through a proton transfer mechanism as suggested by molecular modelling.
Collapse
Affiliation(s)
- A P IJzerman
- Division of Medicinal Chemistry, Leiden/Amsterdam Center for Drug Research, Netherlands
| | | | | | | | | |
Collapse
|
464
|
Evans HH, Mencl J, Ricanati M, Horng MF, Chaudhry MA, Jiang Q, Hozier J, Liechty M. Induction of multilocus mutations at the Tk1 locus after X irradiation of L5178Y cells at different times in the mitotic cycle. Radiat Res 1996; 146:131-8. [PMID: 8693062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
TK1+/- L5178Y-R16 cells were separated into G1, S and G2/M-phase populations by centrifugal elutriation and were treated with 1.5 Gy X radiation. Cells irradiated in the G1 and G2/M phases were most sensitive to the cytotoxic effects of radiation, while cells irradiated in the G2/M phase showed the highest mutant frequency at the thymidine kinase (Tk1) locus. DNA isolated from independent TK1-/- mutants was analyzed for loss of heterozygosity (LOH) at the Tk1 locus and two microsatellites, D11Mit48 and D11Nds7. Homogenates of each mutant were assayed for activity of galactokinase (GLK), the product of the galactokinase (Glk) gene neighboring the Tk1 gene on chromosome 11. Irradiated G1-phase cells had the highest percentage of mutants showing no LOH. The frequency of mutants with LOH at both Tk1 and D11Nds7 with no loss of GLK activity was high in all cell populations: There was no significant difference in the observed frequency of these mutants between the populations. The frequency of mutants losing GLK activity was low, particularly in cells irradiated in the S or G2/M phases. The possibility that the loss of GLK activity is not indicative of LOH at the Glk gene under the conditions of the present experiments is discussed.
Collapse
Affiliation(s)
- H H Evans
- Department of Radiology, Case Western Reserve University, Cleveland, Ohio 44106-4942, USA
| | | | | | | | | | | | | | | |
Collapse
|
465
|
Chen S, Jiang Q, Yu T. Influence of human factors on performance of Chinese speech recognition systems. Space Med Med Eng (Beijing) 1996; 9:235-40. [PMID: 11539905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
Human factors affecting the performance of the speaker dependent isolated Chinese speech recognition system (SRS) were studied. The results showed that the training mode and dialect factors had significant influence upon recognition accuracy; speaker's psychological factor, cooperativeness and educational background had certain influence, while factors such as sex, age, and profession of the speaker had less influence on recognition performance. With the results taken into consideration, ways for improving performance of the speech recognition systems were explored from the point of view of man-machine integration.
Collapse
Affiliation(s)
- S Chen
- Institute of Space Medico-Engineering, Beijing, China
| | | | | |
Collapse
|
466
|
Evans HH, Mencl J, Ricanati M, Horng MF, Chaudhry MA, Jiang Q, Hozier J, Liechty M. Induction of Multilocus Mutations at the Tk1 Locus after X Irradiation of L5178Y Cells at Different Times in the Mitotic Cycle. Radiat Res 1996. [DOI: 10.2307/3579584] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
467
|
Abstract
Peroxynitrite ion (ONO2-) reacted rapidly with CO2 to form a short-lived intermediate provisionally identified as the ONO2CO2- adduct. This adduct was more reactive in tyrosine oxidation than ONO2- itself and produced 3-nitrotyrosine and 3,3'-dityrosine as the major oxidation products. With tyrosine in excess, the rate of 3-nitrotyrosine formation was independent of the tyrosine concentration and was determined by the rate of formation of the ONO2CO2- adduct. The overall yield of oxidation products was also independent of the concentration of tyrosine and medium acidity; approximately 19% of the added ONO2- was converted to products under all reaction conditions. However, the 3-nitrotyrosine/3,3'-dityrosine product ratio depended upon the pH, tyrosine concentration, and absolute reaction rate. These data are in quantitative agreement with a reaction mechanism in which the one-electron oxidation of tyrosine by ONO2CO2- generates tyrosyl and NO2 radicals as intermediary species, but are inconsistent with mechanisms that invoke direct electrophilic attack on the tyrosine aromatic ring by the adduct. Based upon its reactivity characteristics, ONO2CO2- has a lifetime shorter than 3 ms and a redox potential in excess of 1 V, and oxidizes tyrosine with a bimolecular rate constant greater than 2 x 10(5) M-1 s-1. In comparison, in CO2-free solutions, oxidation of tyrosine by peroxynitrite was much slower and gave significantly lower yields (approximately 8%) of the same products. When tyrosine was the limiting reactant, 3,5-dinitrotyrosine was found among the reaction products of the CO2-catalyzed reaction, but this compound was not detected in the uncatalyzed reaction.
Collapse
Affiliation(s)
- S V Lymar
- Department of Chemistry, Washington State University, Pullman 99163-4630, USA
| | | | | |
Collapse
|
468
|
Ge Z, Jiang Q, Taylor DE. Conservation and diversity of the Helicobacter pylori copper-transporting ATPase gene (copA) sequence among Helicobacter species and Campylobacter species detected by PCR and RFLP. Helicobacter 1996; 1:112-7. [PMID: 9398888 DOI: 10.1111/j.1523-5378.1996.tb00020.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND Helicobacter pylori is a causative pathogen of such human stomach diseases as chronic type B gastritis, ulcer, and possibly gastric carcinoma. As a cofactor in various redox enzymes and an essential trace metal required for the synthesis of metalloproteins, copper might play a role in the pathogenesis of H. pylori. A gene, copA, associated with copper transport, has been isolated from H. pylori UA802. In this study, conservation and diversity of this gene were analyzed among some Helicobacter and Campylobacter species. MATERIALS AND METHODS Twenty-one clinical isolates and strains of helicobacters and campylobacters were used in this study. Methods including polymerase chain reaction (PCR) amplification, restriction fragment-length polymorphisms (RFLPs), and hybridization were employed to carry out this work. RESULTS The copA gene was highly conserved in all the H. pylori isolates tested (Helicobacter nemestrinae and Helicobacter felis but not in Helicobacter mustelae and the Campylobacter species), whereas the sequence downstream of the copA appears to diverge among H. pylori isolates. In addition, two restriction patterns of the PCR-amplified copA fragments from seven H. pylori isolates and H. nemestrinae were identified, and the RFLP of H. nemestrinae was identical to that of one of the H. pylori isolate group. CONCLUSIONS The adenosine triposphatase-derived copper-transporting mechanism is employed by various H. pylori strains, H. nemestrinae, H. felis, and perhaps by other Helicobacter species. The nucleotide mutations have risen in the copA gene. It appears that there is a genetic relatedness of the copA gene to H. pylori and H. nemestrinae.
Collapse
Affiliation(s)
- Z Ge
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Canada
| | | | | |
Collapse
|
469
|
Jiang Q, Maclennan JE, Clark NA. Generalized dynamic domain shape calculation in ferroelectric liquid crystals. Phys Rev E Stat Phys Plasmas Fluids Relat Interdiscip Topics 1996; 53:6074-6079. [PMID: 9964967 DOI: 10.1103/physreve.53.6074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
|
470
|
Abstract
Considerable genomic microdiversity has been reported previously among Helicobacter pylori isolates. We have constructed genome maps of four unrelated H. pylori strains (NCTC11637, NCTC11639, UA802 and UA861) using pulsed-field gel electrophoresis (PFGE) with NotI and NruI, hybridization with extracted PFGE DNA fragments and probing with 17 gene probes. These strains of H. pylori were compared with a fifth unrelated H. pylori strain NCTC11638 mapped previously. Considerable diversity in gene arrangement was evident among the five H. pylori maps, and no consistent gene clustering was found. The association of only four genes, katA (catalase gene), vacA (vacuolating cytotoxin gene), hpaA (a putative adhesin gene), and pfr (bacterial ferritin gene) were generally conserved within approximately the same 25% of the genome; however, the order of these genes also varied. Our study demonstrates that macrodiversity, i.e. variability in gene order, in addition to microdiversity, is a characteristic of the H. pylori genome.
Collapse
Affiliation(s)
- Q Jiang
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Canada
| | | | | |
Collapse
|
471
|
Kim J, Jiang Q, Glashofer M, Yehle S, Wess J, Jacobson KA. Glutamate residues in the second extracellular loop of the human A2a adenosine receptor are required for ligand recognition. Mol Pharmacol 1996; 49:683-91. [PMID: 8609897 PMCID: PMC3425639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The A2a adenosine receptor, a member of the G protein-coupled receptor family, is important in the regulation of dopaminergic pathways of the brain and in platelet and cardiovascular functions. In this study, the role of extracellular loops in ligand binding to the human A2a receptor was explored through site-directed mutagenesis. Four glutamate/aspartate residues (Glu151, Glu161, Glu169, and Asp170) in the second extracellular loop (E2) and a cysteine residue (Cys262) in the third extracellular loop (E3) were individually replaced with alanine and other amino acids. A proline residue (Pro173) in E2 was mutated to arginine, the homologous amino acid in A3 receptors. The binding properties of the resultant mutant receptors were determined in transfected COS-7 cells. The mutant receptors were tagged at their amino terminus with a hemagglutinin epitope, thus allowing their detection in the plasma membrane with immunological techniques. High affinity specific binding of [3H]2-[4-[(2-carboxyethyl)phenyl]ethyl-amino]-5'-N-ethylcarboxamidoad eno sine (15 nM) and [3H]8-[4-[[[[2-aminoethyl)-amino]carbonyl]methyl]oxy]phenyl]-1,3- dipropylxanthine (4nM), an A2a agonist and antagonist, respectively, was not observed with four of the mutant receptors, E151A, E151Q, E151D, and E169A, although they were well expressed at the cell surface. The E151A and E169A mutant receptors showed nearly full stimulation of adenylyl cyclase at approximately 10(3)-fold higher concentrations of 2-[4-[(2-carboxyethyl)phenyl]ethyl-amino]-5'-N-ethylcarboxamidoadenosine . The E161A mutant receptor showed as increase in affinity for the nonxanthine adenosine antagonist 9-chloro-2-(furyl)[1,2,4]triazolo[1,5-c]quinazolin-5-amine(6 fold) but not for other ligands. An E169Q mutant gained affinity (5-22 fold) for adenosine derivatives (agonists) substituted at N6 but not at C2 or C5' positions. Mutant receptors D170K and P173R were similar to wild-type receptors in binding of both agonist and antagonist radioligands. A C262G mutant also resembled the wild-type receptor in radioligand binding, indicating that a potential disulfide bridge with another cysteine residue in proximity is not required for the structural integrity of the receptor. Our data suggest that certain amino acids in the second extracellular loop may be directly or indirectly involved in ligand binding.
Collapse
Affiliation(s)
- J Kim
- Molecular Recognition Section, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
| | | | | | | | | | | |
Collapse
|
472
|
Jiang Q, Huang Y, Voigt JM, DeBolt BK, Kominami S, Takemori S, Funae Y, Colby HD. Expression and zonal distribution of CYP2D16 in the guinea pig adrenal cortex: relationship to xenobiotic metabolism. Mol Pharmacol 1996; 49:458-64. [PMID: 8643085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
We recently cloned a CYP2D subfamily member (CYP2D16) from a guinea pig adrenal cDNA library and investigated the expression of CYP2D16 in the guinea pig adrenal cortex and its relationship to adrenal xenobiotic metabolism. A modified sodium dodecyl sulfate-polyacrylamide gel electrophoresis technique revealed three major bands in the molecular mass range of cytochromes P450 in guinea pig adrenal microsomes. Two of the bands were immunoreactive with anti-CYP17 (54 kDa) or anti-CYP21 (52 kDa) antibody. The third band (50 kDa) was immunoreactive with antibody raised against CYP2D1 and with anti-CYP1A1/1A2 antibody. Microsequencing of the 50-kDa band yielded an amino-terminal sequence of 38 amino acids identical to that deducted from the CYP2D16 cDNA. In addition, Northern blot analyses indicated the CYP1A1 was not expressed in the adrenal gland, suggesting that only CYP2D16 composed the microsomal 50-kDa band. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blot analyses demonstrated greater expression of CYP2D16 in microsomes from the inner zone (zona reticularis) of the adrenal cortex than from the outer zones, coinciding with the major site of adrenal xenobiotic metabolism. Bufuralol-1'-hydroxylase activity, a marker for CYP2D isozymes, was also greater in inner- than in outer-zone microsomal preparations and was highly correlated with CYP2D16concentrations. Northern blot analysis with a full-length CYP2D16 cDNA as the probe gave strong bands with adrenal inner zone RNA preparations and relatively weak bands with outer zone RNA. CYP2D16 mRNA was also detectable in liver and kidney RNA preparations, but at lower levels than in the adrenal inner zone, and it was not detectable in testes, lung, intestines, or heart. Overall, the results demonstrate that CYP2D16 is expressed at highest levels in the inner zone of the guinea pig adrenal cortex and suggest a major role for this isozyme in adrenal xenobiotic metabolism.
Collapse
Affiliation(s)
- Q Jiang
- Department of Pharmacology, Philadelphia College of Pharmacy and Science, Pennsylvania 19104, USA
| | | | | | | | | | | | | | | |
Collapse
|
473
|
Chaudhry MA, Jiang Q, Ricanati M, Horng MF, Evans HH. Characterization of Multilocus Lesions in Human Cells Exposed to X Radiation and Radon. Radiat Res 1996. [DOI: 10.2307/3579192] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
474
|
Chaudhry MA, Jiang Q, Ricanati M, Horng MF, Evans HH. Characterization of multilocus lesions in human cells exposed to X radiation and radon. Radiat Res 1996; 145:31-8. [PMID: 8532834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Human TK6 lymphoblasts were exposed to X radiation or radon, and thymidine kinase negative (TK-/-) mutants were selected, isolated and harvested for analysis of structural changes in the TK gene. A large majority (82%) of the radon-induced mutants, 74% of the X-radiation-induced mutants and 45% of the spontaneous mutants lost the entire active TK allele. To analyze these mutants further we measured the loss of heterozygosity at several loci neighboring the TK locus on chromosome 17q. A greater proportion (61%) of the radon-induced mutants than X-radiation-induced or spontaneous mutants harbored the smaller lesions involving the TK allele alone or extending from the TK locus to one or both of the closest neighboring sequences tested. Further, 21% of the X-radiation-induced mutants but only 5% of the radon-induced mutants lost heterozygosity at the col1A1 locus, 31 Mb from the TK gene. These results are in agreement with a recent analysis of radon- and X-radiation-induced lesions inactivating the HPRT gene of TK6 cells, in which we reported that a lower percentage of radon- than X-radiation-induced mutants showed lesions extending to markers 800 kb or more from the HPRT gene on the X chromosome (Bao et al., Mutat. Res. 326, 1-13, 1995). In the present study, we observed that the percentage of slowly growing and very slowly growing TK-/- mutants was greater after treatment with radon than after treatment with X radiation, regardless of the type of lesion present. It is possible, therefore, that the radon-induced lesions are complex and/or less easily repaired, leading to slow growth in a large proportion of the surviving mutant cells.
Collapse
Affiliation(s)
- M A Chaudhry
- Department of Radiology, Case Western Reserve University, Cleveland, Ohio 44106-4942, USA
| | | | | | | | | |
Collapse
|
475
|
Fu P, Mi X, Yu Z, Jiang Q, Zhang Y, Li X. Ultrafast modulation spectroscopy in a cascade three-level system. Phys Rev A 1995; 52:4867-4870. [PMID: 9912828 DOI: 10.1103/physreva.52.4867] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
|
476
|
Jiang Q, Yang H, Wang G. Scaling and dynamics of low-frequency hysteresis loops in ultrathin Co films on a Cu(001) surface. Phys Rev B Condens Matter 1995; 52:14911-14916. [PMID: 9980831 DOI: 10.1103/physrevb.52.14911] [Citation(s) in RCA: 84] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
|
477
|
DeSilva K, Jiang Q, Kuwana T. Chiral separation of naphthalene-2,3-dialdehyde labelled peptides by cyclodextrin-modified electrokinetic chromatography. Biomed Chromatogr 1995; 9:295-301. [PMID: 8580702 DOI: 10.1002/bmc.1130090624] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The chiral separation of several dipeptide enantiomers, derivatized by naphthalene-2,3-dialdehyde (NDA), was achieved by use of cyclodextrin-modified micellar electrokinetic chromatography (CD-MEKC). The dipeptides contained one or two chiral centers. In the case of several dipeptides containing two chiral centers, all four of the optical isomers could be separated and baseline resolved in less than 15 min with 20 mM gamma-CD and 50 mM sodium dodecyl sulphate (SDS) in the background electrolyte. The order of elution of these derivatized dipeptides was explained by considering important chemical equilibria in the SDS, CD and peptide system. Additionally, the influence of geometric location of the chiral center, the structure of the side-chain and the effect of CD concentration on the resolution are discussed.
Collapse
Affiliation(s)
- K DeSilva
- Department of Chemistry and Pharmaceutical Chemistry, University of Kansas, Lawrence 66047, USA
| | | | | |
Collapse
|
478
|
Maclennan JE, Jiang Q, Clark NA. Computer simulation of domain growth in ferroelectric liquid crystals. Phys Rev E Stat Phys Plasmas Fluids Relat Interdiscip Topics 1995; 52:3904-3914. [PMID: 9963863 DOI: 10.1103/physreve.52.3904] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
|
479
|
Jiang Q, Valentini J, Chiew Y. Theoretical Models for Dynamic Dilational Surface Properties of Binary Surfactant Mixtures. J Colloid Interface Sci 1995. [DOI: 10.1006/jcis.1995.1391] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
|
480
|
Tao R, Jiang Q, Sim HK. Finite-element analysis of electrostatic interactions in electrorheological fluids. Phys Rev E Stat Phys Plasmas Fluids Relat Interdiscip Topics 1995; 52:2727-2735. [PMID: 9963719 DOI: 10.1103/physreve.52.2727] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
|
481
|
Salama SM, Jiang Q, Chang N, Sherbaniuk RW, Taylor DE. Characterization of chromosomal DNA profiles from Helicobacter pylori strains isolated from sequential gastric biopsy specimens. J Clin Microbiol 1995; 33:2496-7. [PMID: 7494058 PMCID: PMC228454 DOI: 10.1128/jcm.33.9.2496-2497.1995] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The restriction endonuclease profiles of DNAs from Helicobacter pylori strains isolated from 20 patients in two or more consecutive biopsy specimens over a period of up to 2 years were analyzed by pulsed-field gel electrophoresis with NotI and NruI. H. pylori strains possess a high degree of genomic diversity which was not observed to occur in vivo, and attempts to observe it in vitro were not successful.
Collapse
Affiliation(s)
- S M Salama
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Canada
| | | | | | | | | |
Collapse
|
482
|
Zhang J, Zhang L, Shao Z, Mu X, Jiang Q, Chen H, Jiang M. Observation of multireflections from cat self-pumped phase conjugators with Cu-doped (K<inf>0.5</inf>Na<inf>0.5</inf>)<inf>0.2</inf>(Sr<inf>0.75</inf>Ba<inf>0.25</inf>)<inf>0.9</inf>Nb<inf>2</inf>O<inf>6</inf> crystals and conjugation fidelity analysis. Opt Lett 1995; 20:979. [PMID: 19859396 DOI: 10.1364/ol.20.000979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
|
483
|
Jiang Q, Seyed-Mozaffari A, Sebastian A, Archer S, Bidlack JM. Preventing morphine antinociceptive tolerance by irreversible mu opioid antagonists before the onset of their antagonism. J Pharmacol Exp Ther 1995; 273:680-8. [PMID: 7752070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Irreversible opioid antagonists, when administered at small doses, require several hours to display their antagonism of antinociception mediated by opioid receptors. However, most opioid affinity ligands only need a few minutes to produce wash-resistant inhibition of opioid binding to brain membranes. Our study investigated whether the irreversible antagonists, beta-funaltrexamine (beta-FNA), 14 alpha, 14'beta-[dithiobis[(2-oxo-2,1-ethanediyl)imino]]-7,8-dihydro-N- (cyclopropylmethyl)normorphine (N-CPM-TAMO), and N-cyclopropylmethyl-5 beta-methyl- beta-(p-nitrocinnamoylamino)-7,8-dihydromorphinone (N-CPM-MET-CAMO) had any effect on morphine-induced antinociceptive tolerance before the appearance of their antagonism in the mouse tail-flick assay. All opioids were given by i.c.v. administration. The irreversible antagonists, beta-FNA (20 nmol), N-CPM-TAMO (0.5 nmol) and N-CPM-MET-CAMO (1 nmol) did not produce any antagonism of morphine-induced analgesia until at least 8 hr after administration. Pretreatment with morphine (3 nmol, -140 min) produced acute antinociceptive tolerance as demonstrated by a 45-fold rightward shift of the morphine dose-response curve. When coadministered with morphine, beta-FNA, N-CPM-TAMO and N-CPM-MET-CAMO completely prevented the development of morphine tolerance 140 min after administration in a dose-dependent manner. This preventive effect lasted for up to 420 min, during which time, morphine was given repeatedly up to four times. This antinociception produced by morphine after coadministration with irreversible antagonists was antagonized by naloxone, demonstrating that morphine-induced analgesia was still mediated by opioid receptors. The kappa- and delta-selective opioid antagonists, nor-binaltorphimine and ICI 174,864, respectively, did not block the preventive effect produced by the irreversible antagonists.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
Affiliation(s)
- Q Jiang
- Department of Pharmacology, University of Rochester, School of Medicine and Dentistry, New York, USA
| | | | | | | | | |
Collapse
|
484
|
Jiang Q, Voigt JM, Colby HD. Molecular cloning and sequencing of a guinea pig cytochrome P4502D (CYP2D16): high level expression in adrenal microsomes. Biochem Biophys Res Commun 1995; 209:1149-56. [PMID: 7733969 DOI: 10.1006/bbrc.1995.1617] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Studies were done to characterize a guinea pig adrenal microsomal P450 that had been linked with xenobiotic metabolism in the inner zone of the gland. N-terminal amino acid sequencing of the isolated protein revealed homology with members of the CYP2D subfamily. A human CYPD2D6 cDNA probe was used to screen a guinea pig adrenal cDNA library and a full-length clone was obtained having an open reading frame encoding a 500 amino acid protein. The sequence was found to be highly homologous with all members of the CYP2D subfamily and was designated CYP2D16. The N-terminal sequence of 38 amino acids obtained from the protein microsequencing was identical to that deduced from the nucleotide sequence of the cloned CYP2D16. Northern blot analysis confirmed that CYP2D16 is expressed at high levels in the inner zone of the guinea pig adrenal cortex. The results suggest that CYP2D16 may account, at least in part, for the high rates of xenobiotic metabolism in the guinea pig adrenal.
Collapse
Affiliation(s)
- Q Jiang
- Department of Pharmacology and Toxicology, Philadelphia College of Pharmacy and Science, PA 19104, USA
| | | | | |
Collapse
|
485
|
Wang XB, Tian DC, Jiang Q, Zhang ZH. Effect of fractons on the exciton dynamics in dilute magnets. Phys Rev B Condens Matter 1995; 51:3575-3580. [PMID: 9979167 DOI: 10.1103/physrevb.51.3575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
|
486
|
Lau WA, Ventura S, Jiang Q, Pennefather JN. Endothelin-induced facilitation of sympathetic neurotransmission to the rat vas deferens: effects of suramin. Eur J Pharmacol 1995; 272:31-8. [PMID: 7536159 DOI: 10.1016/0014-2999(94)00624-g] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Experiments were conducted to elucidate the mechanisms of action of endothelins in facilitating neurotransmission to the rat isolated vas deferens. Endothelin-1 and endothelin-3 potentiated field stimulation-induced contractions and those evoked by ATP and alpha, beta-methylene ATP. Responses to noradrenaline were unaffected. The C-terminal hexapeptide, endothelin-(16-21) was without effect on neurotransmission. The facilitation by endothelin-1 of responses to trains of stimulation (10 Hz for 10 s) was absent in the presence of the P2-purinoceptor antagonist, suramin, in concentrations which antagonised the contractile effects of alpha, beta-methylene ATP, but not those of noradrenaline. Suramin did not affect 1,4-dihydro-2,6-dimethyl-5-nitro-4-[2-(trifluoromethyl)- phenyl]-3-pyridine carboxylic acid methyl ester (Bay K 8644)-induced potentiation of contractions in response to field stimulation. These results support the hypothesis that endothelin-induced facilitation of sympathetic neurotransmission to the vas deferens is due to potentiation of the postjunctional effects of the co-transmitter, ATP, acting at P2X-purinoceptors, and indicate that this effect is mediated through actions at endothelin receptors that are not of the ETB-subtype.
Collapse
Affiliation(s)
- W A Lau
- Department of Pharmacology, Monash University, Clayton, Victoria, Australia
| | | | | | | |
Collapse
|
487
|
Jiang Q, Seyed-Mozaffari A, Sebastian A, Archer S, Bidlack JM. Preventing morphine antinociceptive tolerance by irreversible mu opioid antagonists before the onset of their antagonism. ACTA ACUST UNITED AC 1994. [DOI: 10.1016/0167-0115(94)90428-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
488
|
Jiang Q, Chan A, Wang G. Dynamic scaling of island-size distribution in submonolayer growth of 1 x 1 films. Phys Rev B Condens Matter 1994; 50:11116-11120. [PMID: 9975222 DOI: 10.1103/physrevb.50.11116] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
|
489
|
Wang XB, Li JX, Jiang Q, Zhang ZH, Tian DC. Spin-phonon renormalization of the excitation energy in a dilute two-dimensional antiferromagnet. Phys Rev B Condens Matter 1994; 50:7056-7064. [PMID: 9974662 DOI: 10.1103/physrevb.50.7056] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
|
490
|
Jiang Q, Chopp M, Zhang ZG, Helpern JA, Ordidge RJ, Ewing J, Jiang P, Marchese BA. The effect of hypothermia on transient focal ischemia in rat brain evaluated by diffusion- and perfusion-weighted NMR imaging. J Cereb Blood Flow Metab 1994; 14:732-41. [PMID: 8063869 DOI: 10.1038/jcbfm.1994.94] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The effect of moderate whole-body hypothermia (30 degrees C) on transient middle cerebral artery (MCA) occlusion in the rat was evaluated using diffusion- and perfusion-weighted magnetic resonance imaging. Two hours of transient MCA occlusion was induced by intracarotid insertion of a nylon filament under normothermic (n = 14) and hypothermic (n = 7) conditions. Diffusion- and perfusion-weighted imaging were performed before, during, and after focal ischemia from 30 min up to 7 days. In hypothermic animals, scattered neuronal necrosis was localized to select areas of the caudate putamen and the parietal and insular cortex. In contrast, the normothermic ischemic animals exhibited pan-necrosis and infarct encompassing the damaged area. The diffusion and perfusion data measured from caudate putamen indicate that hypothermia causes a significant reduction in the apparent diffusion coefficient of water (ADCw) and CBF values from normothermic control values (p < 0.01). In both normothermic and hypothermic animals after onset of MCA occlusion, ADCw and CBF values in the core of the ischemic region (striatum) significantly declined from the preischemic and homologous contralateral control ADCw and CBF values (p < 0.05). However, ADCw and CBF in the hypothermic group returned toward control more rapidly than in the normothermic group. These results suggest that the protective effect of hypothermia on ischemic cell damage is reflected in the early return of ADCw during reperfusion and the reduction of ischemic cell damage by hypothermia may be mediated by the improved CBF during acute reperfusion.
Collapse
Affiliation(s)
- Q Jiang
- Department of Neurology, Henry Ford Health Sciences Center, Detroit, MI 48202
| | | | | | | | | | | | | | | |
Collapse
|
491
|
|
492
|
Fu P, Yu Z, Mi X, Li X, Jiang Q. Doppler-free ultrafast modulation spectroscopy with phase-conjugation geometry. Phys Rev A 1994; 50:698-708. [PMID: 9910940 DOI: 10.1103/physreva.50.698] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
|
493
|
Archer S, Seyed-Mozaffari A, Jiang Q, Bidlack JM. 14 alpha,14' beta-[Dithiobis[(2-oxo-2,1-ethanediyl)imino]]bis (7,8-dihydromorphinone) and 14 alpha,14' beta-[dithiobis[(2-oxo-2,1- ethanediyl)imino]]bis[7,8-dihydro-N-(cyclopropylmethyl)normorphinone]: chemistry and opioid binding properties. J Med Chem 1994; 37:1578-85. [PMID: 7515442 DOI: 10.1021/jm00037a008] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
14 alpha,14' beta-[Dithiobis[(2-oxo-2,1-ethanediyl)imino]] bis(7,8-dihydromorphinone) (TAMO) (13) was synthesized by condensing 14 beta-amino-7,8-dihydromorphine (4) with acetylthioglycolyl chloride and hydrolyzing the resulting ester with mild base to give a mixture of the thiol 9 and the disulfide 13. Chromatography of the mixture resulted in conversion of the bulk of the thiol 9 to the disulfide 13 by air oxidation. The disulfide 13 was also prepared by condensing the tert-butyldimethylsilyl ether of 4 with the dithiodiglycolyl chloride and treating the resulting product with F- to give the desired product. The pure thiol 9 free of contamination with the disulfide was prepared by treating 13 with excess N-acetyl-L-cysteine and processing the reaction mixture without resorting to chromatography for purification. The corresponding N-(cyclopropylmethyl) nor compound 15 was prepared from the silyl ether 6 and acetylthioglycolyl chloride followed by hydrolysis, treatment with F-, and air oxidation. Incubation of bovine striatal membranes with 13 and 15 resulted in wash-resistant inhibition of the binding of the mu-selective peptide [3H][D-Ala2,(Me)Phe4,Gly(ol)5]-enkephalin (DAMGO). Incubation of membranes with mu but not kappa or delta ligands protected the mu binding sites from alkylation by 13 and 15. The wash-resistant inhibition of mu opioid binding was partially reversed by the addition of the reducing reagent dithiothreitol (DTT). A Scatchard plot of the effect of 13 and 15 on [3H]DAMGO binding showed that these affinity ligands caused a marked decrease in the Bmax value without affecting the Kd value. The wash-resistant inhibition of binding, the reduction in the number of binding sites, the partial reversal of wash-resistant inhibition of binding by DTT, and previously observed long-term antagonism of mu opioid receptors in vivo support the conclusion that 13 and 15 bind covalently to the mu opioid receptor.
Collapse
Affiliation(s)
- S Archer
- Department of Chemistry, Cogswell Laboratory, Rensselaer Polytechnic Institute, Troy, New York 12180-3590
| | | | | | | |
Collapse
|
494
|
Wang XB, Li JX, Jiang Q, Zhang ZH, Tian DC. Effect of fractons in superconductors with fractal structure. Phys Rev B Condens Matter 1994; 49:9778-9781. [PMID: 10009778 DOI: 10.1103/physrevb.49.9778] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
495
|
Akunne HC, Monn JA, Thurkauf A, Jacobson AE, Rice KC, Linders JT, Jiang Q, Porreca F, Rothman RB. An electrophilic affinity ligand based on (+)-MK801 distinguishes PCP site 1 from PCP site 2. Neurochem Res 1994; 19:385-9. [PMID: 8065494 DOI: 10.1007/bf00967314] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The electrophilic affinity ligand, (+)-3-isothiocyanato-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cycl ohepten-5,10 - imine hydrochloride [(+)-MK801-NCS] was characterized for its ability to acrylate phencyclidine (PCP) and sigma binding sites in vivo. Initial studies, conducted with mouse brain membranes, characterized the binding sites labeled by [3H]1-[1-(2-thienyl)cyclohexyl]piperidine ([3H]TCP). The Kd values of [3H]TCP for PCP site 1 (MK801-sensitive) and PCP site 2 (MK801-insensitive) were 12 nM and 68 nM, with Bmax values of 1442 and 734 fmol/mg protein, respectively. Mice were sacrificed 18-24 hours following intracerebroventricular administration of the acylator. The administration of (+)-MK801-NCS increased [3H]TCP binding to site 2, but not to site 1. Although (+)-MK801-NCS decreased [3H](+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d; ccyclohepten-5,10-imine maleate ([3H](+)-MK801) binding to site 1, it had no effect on [3H]TCP binding to site 1. Viewed collectively with other published data, these data support the hypothesis that PCP sites 1 and 2 are distinct binding sites, and that [3H]TCP and [3H](+)-MK801 label different domains of the PCP binding site associated with the NMDA receptor.
Collapse
Affiliation(s)
- H C Akunne
- Clinical Psychopharmacology Section, NIDA/NIH Addiction Research Center, Baltimore, MD 21224
| | | | | | | | | | | | | | | | | |
Collapse
|
496
|
Jiang Q, Sebastian A, Archer S, Bidlack JM. 5 beta-Methyl-14 beta-(p-nitrocinnamoylamino)-7,8-dihydromorphinone and its corresponding N-cyclopropylmethyl analog, N-cyclopropylmethylnor-5 beta-methyl-14 beta-(p-nitrocinnamoylamino)- 7,8-dihydromorphinone: mu-selective irreversible opioid antagonists. J Pharmacol Exp Ther 1994; 268:1107-13. [PMID: 7511163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
5 beta-Methyl-14 beta-(p-nitrocinnamoylamino)-7,8-dihydromorphinone (MET-CAMO) and its corresponding N-cyclopropylmethyl analog, N-cyclopropylmethylnor-5 beta-methyl-14 beta-(p-nitrocinnamoylamino)- 7,8-dihydromorphinone (N-CPM-MET-CAMO) were tested in opioid receptor binding assays and in the mouse tail-flick test in order to characterize the affinity, selectivity and antinociceptive properties of these two compounds. Incubating bovine striatal membranes with either MET-CAMO or N-CPM-MET-CAMO produced a wash-resistant, concentration- and time-dependent inhibition of the binding of the mu-selective ligand, [3H]-[D-Ala2,MePhe4,Gly(ol)5]enkephalin, but with no change in delta or kappa binding. Preincubating membranes with N-CPM-MET-CAMO decreased the maximum binding value for [3H]-[D-Ala2,MePhe4,Gly(ol)5]enkephalin binding without changing the Kd value. In the mouse tail-flick assay, MET-CAMO and N-CPM-MET-CAMO did not produce any antinociception up to a dose of 100 nmol after i.c.v. administration. However, pretreatment of mice with either compound produced a time- and dose-dependent antagonism of morphine-induced antinociception. Analgesia mediated by delta or kappa opioids was not altered by either MET-CAMO or N-CPM-MET-CAMO at a dose of up to 100 nmol. The mu antagonistic effect of 1 nmol of MET-CAMO and N-CPM-MET-CAMO appeared at 8 hr and lasted up to 72 hr, with a maximal effect at 16 to 24 hr after i.c.v. administration. Pretreatment of mice with 1 nmol of MET-CAMO or N-CPM-MET-CAMO, given by i.c.v. administration at -24 hr, produced a rightward and downward shift of dose-response line of i.c.v. morphine.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
Affiliation(s)
- Q Jiang
- Department of Pharmacology, University of Rochester, School of Medicine and Dentistry, New York
| | | | | | | |
Collapse
|
497
|
Jiang Q, Zhang ZG, Chopp M, Helpern JA, Ordidge RJ, Garcia JH, Marchese BA, Qing ZX, Knight RA. Temporal evolution and spatial distribution of the diffusion constant of water in rat brain after transient middle cerebral artery occlusion. J Neurol Sci 1993; 120:123-30. [PMID: 8138799 DOI: 10.1016/0022-510x(93)90262-w] [Citation(s) in RCA: 72] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The regional distribution and temporal evolution of the diffusion coefficient (Dw) of water in rat brain was measured during and after transient middle cerebral artery (MCA) occlusion. Male Wistar rats (n = 14) were subjected to 2 h of middle cerebral artery occlusion, induced by intracarotid insertion of a filament. Diffusion (n = 14) and perfusion (n = 7) weighted magnetic resonance imaging were performed before, and at various time points after MCA occlusion, ranging from 30 min up to 7 days. Our data demonstrate that the temporal profiles of Dw differ between the severely and the least damaged regions of tissue. In the core of the lesion, where the tissue evolved to necrosis, Dw declined significantly (P < 0.001) within 0.5 h after onset of ischemia, and remained depressed until 24 h after withdrawal of the suture. However, no statistically significant decline in Dw was found in the perifocal regions containing morphologically intact cells. Perfusion MRI qualitatively exhibited a hypoperfusion and reperfusion during, and after 2 h MCA occlusion, respectively. A significant (r > or = 0.71, P < 0.01) correlation was found between delta Dw (the difference in Dw between the ipsilateral ischemic and homologous contralateral control regions) obtained immediately before withdrawal of the suture (2 h of ischemia) and at specific early time points after withdrawal of the suture, and the degree of ischemic cell damage. No significant (P > 0.01) correlation was detected at an early time points of ischemia or at other time points after withdrawal of the suture.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
Affiliation(s)
- Q Jiang
- Department of Neurology, Henry Ford Hospital, Detroit, MI 48202
| | | | | | | | | | | | | | | | | |
Collapse
|
498
|
Abstract
Nodule development in the interaction of Glycine soja Sieb. & Zucc. PI468.397 with Bradyrhizobium japonicum USDA110 was studied by hypochlorite clearing and methylene blue staining. Even the earliest stages of nodule development could be observed. The entire length of the primary root was examined up to 15 d postinoculation. Markedly curled root hairs and the first cell divisions in the hypodermal layer (stage I) were observed 2 d postinoculation, and by 3 d cell division activity had spread to the outer layers of the cortex (stage II). Cortical cell division centers not associated with curled root hairs, frequently observed in soybean (Glycine max [L.] Merr.), were very rare in G. soja. The cortical cell division centers that had developed a well-defined nodule meristem (at or beyond stage IV) by 6 d postinoculation continued to develop, but the less-advanced stages became arrested. Almost all nodules developed near the position of the root tip at the time of inoculation. In the parts of the root that developed after inoculation, regions with a high density of markedly curled root hairs per root length were observed. The percentage of the curled root hairs associated with cortical cell division centers, however, declined with each successive peak. Regulation of nodule development in G. soja was similar to that previously reported in soybean, although the rate of nodule development was slower.
Collapse
Affiliation(s)
- D. L. Eskew
- Plant Molecular Genetics, Institute of Agriculture and Center for Legume Research, University of Tennessee, P.O. Box 1071, Knoxville, Tennessee 37901-1071
| | | | | | | |
Collapse
|
499
|
Abstract
It is desirable to have slow-release dosage form to be taken once daily, or at most twice daily, as compared to three or four times in a single day. However, the existing computer-aided dosage form design method requires a large amount of computer time when applied to nonlinear disposition drugs. This large commitment of computer time makes it inconvenient to study the feasibility for prolonged-release products containing such drugs. Instead of evaluating all possible combinations of the amount of dose and release rates that produce acceptable steady-state plasma concentrations, only the contour of the dose-release rate domain needs to be determined. An image boundary tracking method has been used to determine such contours. When combined with several modifications of the numerical solution process, the acceptable dose and release rate constants can be determined efficiently. When this modified boundary tracking method was applied to phenytoin, which exhibits nonlinear disposition, the required computer time was reduced to about 5% of the previous method, making the dosage form feasibility assessment practical.
Collapse
Affiliation(s)
- C F Lam
- Department of Biometry and Epidemiology, Medical University of South Carolina, Charleston 29425-2503
| | | | | |
Collapse
|
500
|
Sebastian A, Bidlack JM, Jiang Q, Deecher D, Teitler M, Glick SD, Archer S. 14 beta-[(p-nitrocinnamoyl)amino]morphinones, 14 beta-[(p-nitrocinnamoyl)amino]-7,8-dihydromorphinones, and their codeinone analogues: synthesis and receptor activity. J Med Chem 1993; 36:3154-60. [PMID: 7693944 DOI: 10.1021/jm00073a015] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
A series of 14 beta-[(nitrocinnamoyl)amino]codeinones and morphinones, some of which contain a 5 beta-methyl group, were prepared from 14 beta-aminocodeinones and 14 beta-[N-(cyclopropylmethyl)-amino]norcodeinones. The affinities of the target compounds for the mu, delta, and kappa opioid receptors were determined by radiolabeled binding experiments using bovine brain membranes. An analogous series of 7,8-dihydrocodeinones and morphinones was prepared and assayed in the same systems. The 3-methoxy derivatives 3 and 4 were more selective than the corresponding morphinones for the mu receptor. The 5 beta-methylcodeinones 25 and 27 had lower affinity at all receptors than the corresponding morphinones, but the 5 beta-methylmorphinones had affinities similar to the morphinones 5 and 6. A similar pattern was observed in the 7,8-dihydro series. Two compounds, 5 beta-methyl-14 beta-[(p-nitrocinnamoyl)amino]-7,8-dihydromorphinone, 20 (MET-CAMO), and N-(cyclopropylmethyl)-14 beta-[(p-nitrocinnamoyl)amino]-7,8-dihydronormorphinone, 22 (N-CPM-MET- CAMO), acted as nonequilibrium ligands in antinociception and membrane binding studies. In mice after icv administration, neither ligand showed any agonist activity but 8-24 h after administration both compounds acted as potent mu antagonists. A Scatchard plot of the effect of N-CPM-MET-CAMO on [3H]DAMGO ([3H]D-Ala2, (Me)-Phe4, Gly(ol)5] enkephalin) binding to bovine striatal membranes showed that there was a significant decrease in the Bmax value and a marginal effect on the Kd value suggesting that the number of binding sites was reduced. When taken together, these results support the view that 20 and 22 bind covalently to the mu receptor. On the other hand, when N-acetylcysteine and 22 were allowed to react in a buffered solution, 22 was recovered unchanged. Under these conditions no Michael reaction was observed.
Collapse
Affiliation(s)
- A Sebastian
- Department of Chemistry, Rensselaer Polytechnic Institute, Troy, New York 12180
| | | | | | | | | | | | | |
Collapse
|