Synthesis and trazodone-like analgesic activity of 4-phenyl-6-aryl-2-[3-(4-arylpiperazin-1-yl)propyl]pyridazin -3-ones

A series of 4,6-diaryl pyridazinones, chemically related to trazodone, ws synthesized and evaluated for analgesic activity. With ED50 values ranging from 8.4 to 46.7 mg kg(-1) i.p. in the phenylbenzoquinone-induced writhing test (PBQ test), most compounds were several times more potent than acetaminophen (ED50 = 231.3 mg kg(-1) i.p.) and noramidopyrine (ED50 = 68.5 mg kg(-1) i.p.). A multiple linear regression analysis demonstrated a correlation between antinociceptive activity and lipophilicity, as well as electronic and steric factors. The most active pyridazinones 2c and 2j exhibited minimal sedative and neurotoxic effects at the dose of 25 mg kg(-1) i.p. They were devoid of activity in the hot plate test and their analgesic activity was not significantly reversed by naloxone in the PBQ test. The antinociceptive response induced by morphine (0.15 mg kg(-1) s.c.) in the PBQ test was greatly potentiated by 2c and 2j administered at the low doses of 1 and 2.5 mg kg(-1) i.p., respectively. On the other hand, their analgesic effects were enhanced synergistically by 5-hydroxytryptophan combined with carbidopa. All these data imply that a significant part of the antinociceptive effect induced by 2c and 2j may involve both opioid and serotonergic pathways. In addition, these two pyridazinones did not exhibit any antidepressant properties in the forced swimming test, nor did they potentiate yohimbine-induced toxicity.     

Synthesis and QSAR of some 3-amino-2-(substituted)aminomethyl-5,6-disubstituted thieno[2,3-d]pyrimidin-4(3H)-ones as novel H1-receptor antagonists

The plasma concentrations of two bone matrix proteins (osteocalcin, osteonectin) were monitored in 56 samples from 14 patients receiving renal transplants and the values compared with serum bone alkaline phosphatase mass concentrations and osteotropic hormone levels (parathyroid hormone, calcitriol). There were no significant changes in the concentrations of plasma osteonectin at any time after transplantation, as compared with the values before transplantation (P > 0.1). None of the plasma samples showed osteonectin levels above the reference interval. There was a weak but significant relationship between platelet counts and plasma osteonectin levels (r = +0.322; P < 0.05). Osteocalcin showed a marked decrease of the values 1 week following transplantation as compared with the values before transplantation without further change of the values 1 and 3 months after transplantation (P > 0.5) whereas 3 months after transplantation bone alkaline phosphatase levels were higher than before transplantation (P < 0.05). Multiple regression analysis (performed with data from 42 samples obtained after transplantation) revealed serum creatinine as an independent predictor of plasma osteocalcin whereas serum calcitriol was an independent predictor of serum bone alkaline phosphatase (P < 0.05). No correlation was observed between serum calcitriol/plasma parathyroid hormone on the one hand and plasma osteocalcin on the other (P > 0.05). After transplantation there was a lack of correlation between serum bone alkaline phosphatase mass concentrations and plasma osteocalcin values (P > 0.05). In conclusion, serum bone alkaline phosphatase should be preferred to bone matrix proteins for the assessment of bone metabolism in patients receiving renal transplants: (a) bone alkaline phosphatase-but not osteocalcin-is significantly correlated with calcitriol and adequately reflects increased bone formation after renal transplantation; (b) interpretation of osteocalcin values is severely hampered by their strong correlation with serum creatinine concentrations; (c) plasma osteonectin determinations are not useful for monitoring bone formation.     

A specific inhibitor of phosphatidylinositol 3-kinase, 2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one (LY294002)

Phosphatidylinositol (PtdIns) 3-kinase is an enzyme implicated in growth factor signal transduction by associating with receptor and nonreceptor tyrosine kinases, including the platelet-derived growth factor receptor. Inhibitors of PtdIns 3-kinase could potentially give a better understanding of the function and regulatory mechanisms of the enzyme. Quercetin, a naturally occurring bioflavinoid, was previously shown to inhibit PtdIns 3-kinase with an IC50 of 1.3 microgram/ml (3.8 microM); inhibition appeared to be directed at the ATP-binding site of the kinase. Analogs of quercetin were investigated as PtdIns 3-kinase inhibitors, with the most potent ones exhibiting IC50 values in the range of 1.7-8.4 micrograms/ml. In contrast, genistein, a potent tyrosine kinase inhibitor of the isoflavone class, did not inhibit PtdIns 3-kinase significantly (IC50 > 30 micrograms/ml). Since quercetin has also been shown to inhibit other PtdIns and protein kinases, other chromones were evaluated as inhibitors of PtdIns 3-kinase without affecting PtdIns 4-kinase or selected protein kinases. One such compound, 2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one (also known as 2-(4-morpholinyl)-8-phenylchromone, LY294002), completely and specifically abolished PtdIns 3-kinase activity (IC50 = 0.43 microgram/ml; 1.40 microM) but did not inhibit PtdIns 4-kinase or tested protein and lipid kinases. Analogs of LY294002 demonstrated a very selective structure-activity relationship, with slight changes in structure causing marked decreases in inhibition. LY294002 was shown to completely abolish PtdIns 3-kinase activity in fMet-Leu-Phe-stimulated human neutrophils, as well as inhibit proliferation of smooth muscle cells in cultured rabbit aortic segments. Since PtdIns 3-kinase appears to be centrally involved with growth factor signal transduction, the development of specific inhibitors against the kinase may be beneficial in the treatment of proliferative diseases as well as in elucidating the biological role of the kinase in cellular proliferation and growth factor response.     

YM022 [(R)-1-[2,3-dihydro-1-(2''-methylphenacyl)-2-oxo-5-phenyl-1H-1,4- benzodiazepin-3-yl]-3-(3-methylphenyl)urea]: an irreversible cholecystokinin type-B receptor antagonist

It is controversial whether osteopontin (OP) is expressed in glomeruli and involved in glomerular diseases. We examined whether the OP expression is present at gene and protein levels in cultured rat mesangial cells (MCs). Northern blotting revealed a 1.7 kb OP-mRNA expression in MCs. Fetal calf serum (FCS) and TNF-alpha increased OP gene expression in serum-starved MCs by 2.7- and 1.8-fold over 24- and 12-hour periods, respectively. PDGF, IL-1beta, and TGF-beta had little effect on OP gene expression. Western blotting detected the OP protein expression (69 kDa). FCS and TNF-alpha increased OP protein expression in serum-starved MCs over 48- and 24-hour periods, respectively. The present study clearly demonstrated the expression of OP gene and protein in cultured rat MCs. Increased OP production under serum or TNF-alpha stimulation suggests that intraglomerular OP may contribute to the development of glomerular diseases.     

Structure-activity relationships of 4-(phenylethynyl)-6-phenyl-1,4-dihydropyridines as highly selective A3 adenosine receptor antagonists

4-(Phenylethynyl)-6-phenyl-1,4-dihydropyridine derivatives are selective antagonists at human A3 adenosine receptors, with Ki values in a radioligand binding assay vs [125I]AB-MECA (N6-(4-amino-3-iodobenzyl)-5'-(N-methylcarbamoyl)adenosine) in the submicromolar range. In this study, structure-activity relationships at various positions of the dihydropyridine ring (the 3- and 5-acyl substituents, the 4-aryl substituent, and 1-methyl group) were probed synthetically. Using the combined protection of the 1-ethoxymethyl and the 5-[2-(trimethylsilyl)ethyl] ester groups, a free carboxylic acid was formed at the 5-position allowing various substitutions. Selectivity of the new analogues for cloned human A3 adenosine receptors was determined vs radioligand binding at rat brain A1 and A2A receptors. Structure-activity analysis at adenosine receptors indicated that pyridyl, furyl, benzofuryl, and thienyl groups at the 4-position resulted in, at most, only moderate selectivity for A3 adenosine receptors. Ring substitution (e.g., 4-nitro) of the 4-phenylethylnyl group did not provide enhanced selectivity, as it did for the 4-styryl-substituted dihydropyridines. At the 3-position of the dihydropyridine ring, esters were much more selective for A3 receptors than closely related thioester, amide, and ketone derivatives. A cyclic 3-keto derivative was 5-fold more potent at A3 receptors than a related open-ring analogue. At the 5-position, a homologous series of phenylalkyl esters and a series of substituted benzyl esters were prepared and tested. (Trifluoromethyl)-, nitro-, and other benzyl esters substituted with electron-withdrawing groups were specific for A3 receptors with nanomolar Ki values and selectivity as high as 37000-fold. A functionalized congener bearing an [(aminoethyl)amino]carbonyl group was also prepared as an intermediate in the synthesis of biologically active conjugates.     

Synthesis of racemic 6,7,8,9-tetrahydro-3-hydroxy-1H-1-benzazepine-2,5-diones as antagonists of N-methyl-d-aspartate (NMDA) and alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptors

The synthesis and pharmacological properties of several racemic 6,7,8,9-tetrahydro-3-hydroxy-1H-1-benzazepine-2,5-diones (THHBADs) are described. Synthesis was accomplished via a Schmidt reaction with 5,6,7,8-tetrahydro-2-methoxynaphthalene-1,4-diones (THMNDs) followed by demethylation. THMNDs were prepared via a Diels-Alder reaction with 2-methoxybenzoquinone (5) or 2-bromo-5-methoxybenzoquinone (14) and substituted 1,3-butadienes. The pharmacology of THHBADs was characterized by electrical recordings in Xenopus oocytes expressing rat brain NMDA and AMPA receptors. THHBADs are antagonists of NMDA and AMPA receptors with functional potency being dependent upon the substitution pattern on the tetrahydrobenzene moiety. The 7,8-dichloro-6-methyl (18a) and 7,8-dichloro-6-ethyl (18b) analogs are the most potent THHBADs prepared and have apparent antagonist dissociation constants (Kb values) of 0.0041 and 0.0028 microM, respectively, for NMDA receptors and 0.51 and 0.72 microM, respectively, for AMPA receptors.     

Structure-activity relationships of 4-hydroxy-3-nitroquinolin-2(1H)-ones as novel antagonists at the glycine site of N-methyl-D-aspartate receptors

A series of 4-hydroxy-3-nitroquinolin-2(1H)-ones (HNQs) was synthesized by nitration of the corresponding 2,4-quinolinediols. The HNQs were evaluated as antagonists at the glycine site of NMDA receptors by inhibition of [3H]DCKA binding to rat brain membranes. Selected HNQs were also tested for functional antagonism by electrophysiological assays in Xenopus oocytes expressing either 1a/2C subunits of NMDA receptors or rat brain AMPA receptors. The structure-activity relationships (SAR) of HNQs showed that substitutions in the 5-, 6-, and 7-positions in general increase potency while substitutions in the 8-position cause a sharp reduction in potency. Among the HNQs tested, 5,6,7-trichloro HNQ (8i) was the most potent antagonist with an IC50 of 220 nM in [3H]DCKA binding assay and a Kb of 79 nM from electrophysiological assays. Measured under steady-state conditions HNQ 8i is 240-fold selective for NMDA over AMPA receptors. The SAR of HNQs was compared with those of 1,4-dihydroquinoxaline-2,3-diones (QXs) and 1,2,3,4-tetrahydroquinoline-2,3,4-trione 3-oximes (QTOs). In general, HNQs have similar potencies to QXs with the same benzene ring substitution pattern but are about 10 times less active than the corresponding QTOs. HNQs are more selective for NMDA receptors than the corresponding QXs and QTOs. The similarity of the SAR of HNQs, QXs, and QTOs suggested that these three classes of antagonists might bind to the glycine site in a similar manner. With appropriate substitutions, HNQs represent a new class of potent and highly selective NMDA receptor glycine site antagonists.     

Study on major metabolites of 3H-1,2-dihydro-2-(4-methylphenylamino)-methyl-1-pyrrolizinone in rabbits]

The metabolites of a 750 mg oral dose of Z-47 [3H-1, 2-dihydro-2-(4-methylphenylamino) methyl-1-pyrrolizinone], a new anti-inflammatory and analgesic agent, in rabbit urine were separated and detected with high performance liquid chromatographic method. On basis of the chromatographic behavior of Z-47 metabolites and biotransformation pathways of drugs with partial structure of Z-47, the carboxylic derivative of Z-47 [4-(3H-1, 2-dihydro-1-pyrrolizinone-2-methylamino) benzoic acid] was proposed as a potential metabolite so that the compound was synthesized. The authentic substance was then compared with one of the metabolites by the chromatographic retention time and the ratio of their UV-absorbances at two wavelengths. The enzyme-hydrolyzed product of another metabolite was also analysed. It was consequently confirmed that the carboxylic derivative of Z-47 and its acyl beta-D-glucuronide are major metabolits of Z-47 in rabbits.     

1-(4-硝基苯基)-3-(3,5-二溴吡啶)三氮烯的合成及其与铜的显色反应

合成了显色剂1-(4-硝基苯基)-3-(3,5-二溴吡啶)三氮烯(NPDBPDT),并研究了其与铜的显色反应。在pH11.0的Na2B4O7-NaOH缓冲溶液介质中,表面活性剂OP存在下,铜与NPDBPDT生成组成比为1∶4的络合物。该络合物在460nm处有最大正吸收峰,540nm处有最大负吸收峰,以540nm为参比波长,460nm为测量波长进行双波长测定络合物的吸光度。体系表观摩尔吸光系数为2.02×105L.mol-1.cm-1,铜量在8～480μg/L范围内符合比尔定律,方法检出限为7.43×10-9g/mL。所拟方法用于铜矿和铝合金样品中铜的测定,结果与原子吸收光谱法相吻合,相对标准偏差分别为1.63%和1·56%。     

Synthesis and in vitro microsomal metabolism of 4-ethyl-5-(4-fluorophenyl)-2,4-dihydro-3H-1,2,4-triazole-3-thione and its potential metabolites

Although most triazoline-3-thione derivatives (cyclic thiosemicarbazides) are important compounds possessing some biological and pharmacological activities, no literature was found showing their metabolic reactions with hepatic microsomal preparations. We, therefore, planned to study the in vitro microsomal metabolism of a prototype, 4-ethyl-5-(4-fluorophenyl)-2,4-dihydro-3H-1,2,4-triazole-3-thione (A). The substrate (A) and its potential metabolites i.e. the corresponding dealkylation (A1), desulphuration (A2) and S-oxidation (A3) products were synthesized and characterized by spectral methods. The substrate and its potential metabolites were separated by a reverse phase HPLC. A was incubated with rat microsomal preparations fortified with NADPH and extracted into DCM; concentrated under a stream of N2 at 20 degrees C and analyzed by HPLC. The results indicated that A was metabolically inert and failed to produce the corresponding desulphuration (triazole-3-one) and S-oxidation (sulphenic acid) metabolites which would lead to pharmacological and toxicological alterations compared to the parent molecule. However, a small amount of dealkylated product (A1) was observed as a metabolite together with two unidentified metabolites.     

Photolysis of 4-amino-, 4-alkoxy- and 4-Hydroxy-2,3-dimethyl-1-phenyl-3-pyrazolin-5-ones (author''s transl)

Clinical and hemodynamic results have been evaluated 12--24 months after mitral valve replacement with the new Bj?rk-Shiley tilting disc valve prosthesis. After operation, most patients were improved symptomatically and were classified as I-II (N.Y.H.A.). No patient became worse. Hemodynamic status at rest showed significant reduction in pulmonary capillary venous pressure, pulmonary artial pressure and significant increase in cardiac output when compared with the preoperative values, but postoperative hemodynamic abnormalities remained. Exercise produced a rise in pressures in the pulmonary circuit and in cardiac output. The increase in cardiac output was less than expected from the increase in oxygen consumption, with a few exceptions. Apparently, there was no close relationship between the symptomatic improvement and the hemodynamic results. Thus, the present study points to the importance of hemodynamic data in the objective assessment of the results of cardiac surgery.     

Synthesis and Characterization of Some Lanthanide（Ⅲ） Complexes with 4- [N-（2-methoxy benzylinine）formy1]-2, 3-dimethyl-1-phenyl-3-pyazolin-5-one

A series of seven novel lanthanide（Ⅲ ） nitrato complexes with 4-[ N-（2-methoxybenzylimine）formyl] 1-2, 3- dimethyl-1-phenyl-3-pyazolin-5-one （2mbfa）, were synthesized. These complexes were characterized by elemental analysis, molecular mass determination, conductance and magnetic moment measurements, IR, UV-visible, and ^13CNMR spectral studies, In these complexes, the Schiff base, 2mbfa, acts as neutral bidentate ligand by utilizing the carbonyl oxygen and azomethine nitrogen as donor sites. All the three nitrate ions are also coordinated unidentately with 7 coordination for the lanthanide（Ⅲ） ions with a tentative monocapped octahedral geometry for the complexes. All the seven lanthanide（Ⅲ） complexes have a general formula, [ Ln（2mbfa）：（NO3）3 ].     

Structure-activity relationships of non-peptide vasopressin V1a antagonists: 1-(1-multi-substituted benzoyl 4-piperidyl)-3,4-dihydro-2(1H)-quinolinones

During our systematic studies on the arginine vasopressin receptor V1a-antagonistic activity of 1-(1-benzoyl substituted 4-piperidyl)-3,4-dihydro-2(1H)-quinolinones, we found a general substituent effect on the benzene ring. Hydrogen-bonding ability at the ortho position was especially important for enhancement of the affinity of multi-substituted analogs. Details of the syntheses and structure-activity relationships for this series are presented.     

(1S,2R)-D-erythro-2-(N-myristoylamino)-1-phenyl-1-propanol as an inhibitor of ceramidase

In this study, we have examined the cellular and biochemical activities of the ceramide analog (1S,2R)-D-erythro-2-(N-myristoylamino)-1-phenyl-1-propanol (D-erythro-MAPP). Addition of 5 microM D-e-MAPP to HL-60 human promyelocytic leukemia cells resulted in a concentration- and time-dependent growth suppression accompanied by an arrest in the G0/G1 phase of the cell cycle; thus mimicking the action of exogenous ceramides. Its enantiomer L-e-MAPP was without effect. Two lines of evidence suggested that D-e-MAPP may not function as a direct analog of ceramide. First, D-e-MAPP possesses a stereochemical configuration opposite to that of D-erythro-ceramide. Second, D-e-MAPP failed to activate ceramide-activated protein phosphatase in vitro. Therefore, we examined if D-e-MAPP functioned indirectly by modulating endogenous ceramide levels. The addition of D-e-MAPP to cells, but not L-e-MAPP, caused a time- and concentration-dependent elevation in endogenous ceramide levels reaching greater than 3-fold over baseline following 24 h of treatment. Both D-e-MAPP and L-e-MAPP underwent similar uptake by HL-60 cells. D-e-MAPP was poorly metabolized, and remained intact in cells, whereas L-e-MAPP underwent a time- and concentration-dependent metabolism; primarily through N-deacylation. In vitro, L-e-MAPP was metabolized by alkaline ceremidase to an extent similar to that seen with C16-ceramide. D-e-MAPP was not metabolized. Instead, D-e-MAPP inhibited alkaline ceramidase activity in vitro with an IC50 of 1-5 microM. D-e-MAPP did not modulate the activity of other ceramide metabolizing enzymes in vitro or in cells, and it was a poor inhibitor of acid ceramidase (IC50>500 microM). Finally, D-e-MAPP inhibited the metabolism of L-e-MAPP in cells. These studies demonstrate that D-e-MAPP functions as an inhibitor of alkaline ceramidase in vitro and in cells resulting in elevation in endogenous levels of ceramide with the consequent biologic effects of growth suppression and cell cycle arrest. These studies point to an important role for ceramidases in the regulation of endogenous levels of ceramide.     

Structural optimization affording 2-(R)-(1-(R)-3, 5-bis(trifluoromethyl)phenylethoxy)-3-(S)-(4-fluoro)phenyl-4- (3-oxo-1,2,4-triazol-5-yl)methylmorpholine, a potent, orally active, long-acting morpholine acetal human NK-1 receptor antagonist

Structural modifications requiring novel synthetic chemistry were made to the morpholine acetal human neurokinin-1 (hNK-1) receptor antagonist 4, and this resulted in the discovery of 2-(R)-(1-(R)-3, 5-bis(trifluoromethyl)phenylethoxy)-3-(S)-(4-fluoro)phenyl-4-(3-ox o-1 ,2,4-triazol-5-yl)methyl morpholine (17). This modified compound is a potent, long-acting hNK-1 receptor antagonist as evidenced by its ability to displace [125I]Substance P from hNK-1 receptors stably expressed in CHO cells (IC50 = 0.09 +/- 0.06 nM) and by the measurement of the rates of association (k1 = 2.8 +/- 1.1 x 10(8) M-1 min-1) and dissociation (k-1 = 0.0054 +/- 0.003 min-1) of 17 from hNK-1 expressed in Sf9 membranes which yields Kd = 19 +/- 12 pM and a t1/2 for receptor occupancy equal to 154 +/- 75 min. Inflammation in the guinea pig induced by a resiniferatoxin challenge (with NK-1 receptor activation mediating the subsequent increase in vascular permeability) is inhibited in a dose-dependent manner by the oral preadmininstration of 17 (IC50 (1 h) = 0.008 mg/kg; IC90 (24 h) = 1.8 mg/kg), indicating that this compound has good oral bioavailbility and peripheral duration of action. Central hNK-1 receptor stimulation is also inhibited by the systemic preadministration of 17 as shown by its ability to block an NK-1 agonist-induced foot tapping response in gerbils (IC50 (4 h) = 0.04 +/- 0.006 mg/kg; IC50 (24 h) = 0.33 +/- 0.017 mg/kg) and by its antiemetic actions in the ferret against cisplatin challenge. The activity of 17 at extended time points in these preclinical animal models sets it apart from earlier morpholine antagonists (such as 4), and the piperidine antagonists 2 and 3 and could prove to be an advantage in the treatment of chronic disorders related to the actions of Substance P. In part on the basis of these data, 17 has been identified as a potential clinical candidate for the treatment of peripheral pain, migraine, chemotherapy-induced emesis, and various psychiatric disorders.     

(3SR,4aRS,6SR,8aRS)-6-(1H-tetrazol-5-yl)decahydroisoquinoline-3-carboxylic acid, a novel, competitive, systemically active NMDA and AMPA receptor antagonist

We report the synthesis and characterization of 6 (LY246492), which is a competitive N-methyl-D-aspartate (NMDA) and 2-amino-3-(3-hydroxy-5-methylisoxazol-4-yl)propanoic acid (AMPA) receptor antagonist. Tetrazole-substituted amino acid 6 was prepared in four steps from the recently described aldehyde 7. The optical isomers (-)-6 and (+)-6 were obtained from the same sequence of reactions using the corresponding isomers of 7. The compound displaces both NMDA and AMPA receptor binding and antagonizes depolarizations in cortical slices evoked by both NMDA and AMPA. In mice and pigeons, the compound showed antagonism of responses mediated through NMDA and AMPA receptors. Using the resolved optical isomers of 6, both NMDA and AMPA antagonist activities were found to reside in a single isomer, (-)-6.     

Studies on nonpeptide angiotensin II receptor antagonists. III. Synthesis and biological evaluation of 5-alkylidene-3,5-dihydro-4H-imidazol-4-one derivatives

The ITS-2 sequences from seven worms of the Japanese triploid form of Fasciola, two of Fasciola hepatica from Uruguay and four of Fasciola gigantica from Zambia and Indonesia were determined. The ITS-2 sequences of the Japanese triploid worms were divided into two distinct types, one of which was almost identical to that of F. hepatica and the other to F. gigantica from Indonesia.     

2''-(Trimethylammonio)ethyl 4-(hexadecyloxy)-3(S)-methoxybutanephosphonate: a novel potent antineoplastic agent

The ability to successfully reuse OKT3, a mouse monoclonal antibody, is dependent upon the host's response to the antibody during and following the first treatment course. Antiidiotypic and/or antiisotypic antibodies may develop after exposure to OKT3. Antiidiotypic antibodies will bind OKT3, rendering it ineffective, while antiisotypic antibodies do not influence the efficacy of OKT3. A new membrane-based immunoassay, Transtat OKT3 (Sangstat Medical Corp, Menlo Park, CA) detects anti-OKT3 antibodies in less than 15 min. It allows simultaneous detection of antiidiotype and antiisotype antibodies. A total of 180 serum samples were initially analyzed by ELISA; results were negative, low-titer (1:100), or high-titer (> or = 1:1000). Retrospectively, these same samples were analyzed by Transtat for both anti-OKT3 (idiotype) and IgG2a (isotype). A total of 109 samples of 180 (60.6%) tested negative by ELISA and Transtat, while 71 (39.4%) tested positive. Of the negative samples by ELISA, 98 of 109 (89.9%) also tested anti-OKT3-negative by Transtat. Of the 109 specimens that were anti-OKT3 negative by Transtat, 98 (89.9%) tested negative by ELISA. There were 22 discrepant samples between the two methods; all were low-titer-positive (ELISA and Transtat). The 71 positive ELISA samples consisted of 53 low-titer (1:100) and 18 high-titer (> or = 1:1000), while the 71 anti-OKT3 positive Transtat samples consisted of 44 low-titer (1:10) and 27 high-titer (1:50). Sixty of 71 (84.5%) ELISA-positive samples were also positive by Transtat. Similarly, 60 of 71 (84.5%) Transtat-positive samples were also positive by ELISA. Of 71 patient samples positive for anti-OKT3 antibodies, 63 had an antiisotypic component present by Transtat. In conclusion, the Transtat OKT3 assay for measuring OKT3 and IgG2a antibodies offers a rapid and accurate assay for OKT3 monitoring.     

4-[(1H-imidazol-4-yl) methyl] benzamidines and benzylamidines: novel antagonists of the histamine H3 receptor

A series of amidine substituted phenyl-, benzyl-, and phenethylimidazoles based on the known H3 agonist SK&F 91606 (4) has been synthesized and tested as ligands for the histamine H3 receptor. Insertion of a phenyl ring between the imidazole ring and the amidine moiety produces antagonists. The benzyl series was found to be the most potent and was further investigated. Compounds 9c and 18 (entries 5 and 12, Table 1) are potent ligands for the H3 receptor with K(i) values of 16 nM and 7.2 nM respectively. In vivo, both compounds were shown to be equipotent to thioperamide (2), the standard H3 antagonist.