Simultaneous analysis of the nasal shedding kinetics of field and vaccine strains of Bordetella bronchiseptica

Groups of four two-week-old puppies were administered serial dilutions of an intranasal vaccine containing live Bordetella bronchiseptica and canine parainfluenza virus vaccine and housed individually in isolator cages. Three vaccinated groups and one unvaccinated control group were exposed to virulent B bronchiseptica four weeks after vaccination and evaluated. Nasal swabs for bacterial culture and sera for agglutination tests were taken from all the dogs every week for four weeks. The bacteria isolated were identified by growth on specific agar and by specific PCR to distinguish between vaccine and challenge strains. The vaccine strain persisted in the nasal cavity after vaccination but no adverse reactions were observed. Serum agglutination titres were raised in the vaccinated dogs at challenge. Vaccine strains were not isolated after the challenge from most of the vaccinated dogs. The challenge strain was shed in the dogs vaccinated with the lowest dose (10(6.0) cfu/dose) for two to three weeks but the other vaccinated groups (10(7.0) and 10(8.0) cfu/dose) shed the challenge strain transiently or not at all. Only the group vaccinated with 10(6.0) cfu/dose exhibited clinical signs after challenge.

Potential nootropic agents, 4-alkoxy-2-(1-piperazinyl)quinazoline derivatives

A series of 4-alkoxy-2-(1-piperazinyl)quinazoline derivatives was synthesized and evaluated for its ability to reverse a scopolamine-induced learned impairment in a one-trial passive avoidance task (antiamnestic activity). 2-(4-Allyl-1-piperazinyl)-4-pentyloxyquinazoline (4) showed more potent antiamnestic activity than such reference compounds as aniracetam, idebenone and bifemelane at a wide dose range (1-30 mg/kg]. Compound 4 also exhibited potent anticonvulsive and antihypoxic activities, and was selected as the most promising nootropic candidate agent.

Novel 4-substituted 2-piperazinylquinazolines as potent anticonvulsive and antihypoxic agents

Several types of quinazoline derivatives were prepared and examined for anticonvulsive and antihypoxic activities. Many compounds showed potent anticonvulsive activity, and their anticonvulsive profile is similar to that of phenytoin. The analysis of quantitative structure-activity relationships indicated that the anticonvulsive activity was parabolically related to the lipophilicity of the compounds. Most of the 4-alkoxyquinazolines showed potent anticonvulsive and antihypoxic activities. It is confirmed that there is a good correlation between the potencies of these activities.

Novel 4-phenoxy-2-(1-piperazinyl)quinazolines as potent anticonvulsive and antihypoxic agents

A series of 4-phenoxy-2-(1-piperazinyl)quinazolines was synthesized and examined for anticonvulsive and antihypoxic activities. Many of the compounds exhibited potent anticonvulsive activity comparable to that of carbamazepine or phenytoin. Among them, 4-phenoxy-2-(4-propyl-1-piperazinyl)quinazoline (5w) was selected as the most promising candidate antiepileptic drug with few side effects. It seemed that potent anticonvulsive activity was a prerequisite for potent antihypoxic activity.

Benzylpiperazine derivatives. XI. Synthesis of compounds related to the metabolites of 1-[bis(4-fluorophenyl)methyl]-4-(2,3,4-trimethoxybenzyl)piperazine dihydrochloride (KB-2796)

The metabolites of 1-[bis(4-fluorophenyl)methyl]-4-(2,3,4-trimethoxybenzyl)piperazine dihydrochloride (KB-2796, 1), a cerebral vasodilator, and related compounds were synthesized to confirm the proposed structures. The structures of the metabolites (3-5) in rats were identified by means of synthesis of the authentic compounds.

Bioisosteric transformation of H1-antihistaminic benzimidazole derivatives

With the aim of obtaining new H1-antihistaminic agents, transformations of previously reported antihistaminic benzimidazoles were performed on the basis of the concept of bioisosterism. Among the compounds prepared, imidazo[4,5-b]pyridine (8) and 4(3H)-quinazolinone (11) exhibited significant H1-antihistaminic activity.

Quantitative structure-activity relationships of H1-antihistaminic benzimidazole derivatives

The quantitative structure-activity relationships (QSAR) of 2-(4-substituted-1-piperazinyl)benzimidazole derivatives for antihistaminic activity were examined. Taking into consideration the specific conformations of some derivatives, a significant correlation was obtained using Verloop's STERIMOL parameters B3 and L of the substituent at the 1-position of the benzimidazole nucleus. The results indicated that the derivatives having a substituent with a small breadth and an appropriate length at the 1-position showed potent activity. From the results, a model of the binding site is proposed. The QSAR of side effects (anticholinergic activity and central nervous system depressive effect) were also examined and the results showed that a sterically small substituent at the 1-position was required to decrease side effects.

Syntheses of the metabolites of 1-(2-ethoxyethyl)-2-(hexahydro-4-methyl-1H-1,4-diazepin-1-yl)-1H benzimidazole difumarate (KG-2413) and related compounds

The metabolites of 1-(2-ethoxyethyl)-2-(hexahydro-4-methyl-1H-1,4-diazepin-1-yl)-1H-b enzimidazole difumarate (KG-2413), which has a potent H1-antihistaminic activity, were predicted on the basis of metabolic studies of related compounds and were synthesized to aid in identification of the actual metabolites and for examination of their antihistaminic activity. Among the twelve compounds prepared, nine compounds were actually found as the metabolites of KG-2413 in rat urine. The antihistaminic activities of these metabolites were found to be lower than that of KG-2413.

Synthesis of 2-(4-substituted-1-piperazinyl)benzimidazoles as H1-antihistaminic agents

A series of 2-(4-substituted-1-(homo)piperazinyl)benzimidazoles was prepared and tested for H1-antihistaminic activity in vitro and in vivo. Most of the compounds showed antihistaminic activity and some of the 1-[2-(substituted-oxy)ethyl] derivatives exhibited potent activity. In a structure-activity comparison it was found that the oxygen atom in the 2-(substituted-oxy)ethyl group at the 1-position of the benzimidazole nucleus played an important role for potent antihistaminic activity, especially in vivo. One of the most potent compounds, 1-(2-ethoxyethyl)-2-(4-methyl-1-homopiperazinyl)benzimidazole (69), was 39 times more potent than chlorpheniramine maleate in H1-antihistaminic activity in vivo and was selected for clinical evaluation. The structure of compound 69 is of interest because it provides only a single aromatic unit linked through a chain to a basic nitrogen, while most H1-antihistaminic agents have structures that comprise a double-aromatic unit linked through a chain to a basic tertiary amino group.