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PubMed1987

Cardiovascular responses to a newly developed cardiotonic agent, ZSY-39 [4-methyl-5-(4-pyridinyl)-thiazole-2-carboxyamide] in dog cross-circulated atrial and ventricular preparations.

The cardiovascular effects of ZSY-39 [4-methyl-5-(4-pyridinyl)-thiazole-2-carboxyamide] were investigated in isolated and blood-perfused atrial and ventricular muscles perfused with donor's arterial blood. When ZSY-39 was given i.v. to the intact donor dog, hypotension with a slight tachycardia was induced at a dose range of 30-1,000 micrograms/kg. At the same time, slight positive chronotropic and inotropic responses appeared in isolated, perfused atria at i.v. doses of 300 and 1,000 micrograms/kg ZSY-39, indicating a relatively dominant inotropic action. Direct injection of ZSY-39 into the cannulated sinus node artery of the isolated atrium produced positive chronotropic and inotropic responses in a dose-related manner (1 to 300 micrograms). ZSY-39 also induced a dose-dependent increase in developed tension in the isolated ventricle. The positive chronotropic and inotropic effects of ZSY-39 were not modified by an adequate dose of propranolol which completely blocked norepinephrine-induced positive chronotropic and inotropic responses. From these results, it is concluded that ZSY-39 has mild cardiotonic properties, showing relatively selective positive inotropic activity.

Animals↗
PubMed2000

N-hydroxy-4-(4-chlorophenyl)thiazole-2(3H)-thione as a photochemical hydroxyl-radical source: photochemistry and oxidative damage of DNA (strand breaks) and 2'-deoxyguanosine (8-oxodG formation).

On irradiation of N-hydroxythiazole-2(3H)-thione 3 at 300 nm, the photoproducts disulfide 4, bisthiazole 5 and thiazole 6 are formed. During this photolysis, hydroxyl radicals are released, which have been detected by spin trapping with 5,5-dimethyl-1-pyrroline N-oxide (DMPO), coupled with electron paramagnetic resonance spectroscopy. In the presence of supercoiled pBR322 DNA, irradiation of thiazolethione 3 induces strand breaks through the photogenerated hydroxyl-radicals, as confirmed by control experiment with the hydroxyl-radical scavenger isopropanol. Singlet oxygen appears not to be involved, as attested by the lack of a D2O isotope effect. During the photoreaction of thiazolethione 3 in the presence of 2'-deoxyguanosine (dG), the latter is photooxidized (ca 10% conversion after 2 h of irradiation) to the 7,8-dihydro-8-oxo-2'-deoxyguanosine as the main oxidation product. The dG conversion levels off after complete consumption of thiazolethione 3 and is suppressed by the addition of the hydroxyl-radical scavenger 2,6-di-tert-butylcresol or DMPO. Since the photoproducts 4-6 are ineffective as sensitizers for the photooxidation of dG and DNA, the hydroxyl radicals released in the photolysis of thiazolethione 3 are the oxidizing species of DNA and dG. These results suggest that the thiazolethione 3 may serve as a novel and effective photochemical hydroxyl-radical source for photobiological studies.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed1999

Thiazole derivatives as inhibitors of purified bovine liver mitochondrial monoamine oxidase-B: structure-activity relationships and theoretical study.

Structure-activity relationships were performed on a new series of thiazole derivatives which selectively inactivate monoamine oxidase-B (MAO-B), purified from mitochondrial beef liver. All of the synthesized and tested compounds showed non-competitive inhibition, suggesting the formation of a stable adduct between the tertiary amine function, linked to the thiazolyl derivatives and the active site of the enzyme. The mechanism of MAO-B inhibition is discussed in terms of the Ionization Potential of the amine nitrogen atom and the conformational flexibility of the inhibitors.

Animals↗
PubMed1977

Amino acids and derivatives of thiazole-4-carboxylic acid as constituents of thiopeptin B.

L-Alanine, L-threonine, L-valine, D-cystine and three derivatives of thiazole-4-carboxylic acid (thiostreptin, 1-aminomethylthiazole-4-carboxylic acid and thiostreptoic acid) were isolated from the acid-hydrolysate of thiopeptin B. In addition, the presence of dehydrobutyrine and dehydroalanine residues in the antibiotic was determined. Other components remain unidentified.

Amino Acids↗
PubMedDate not supplied

Synthesis and antimicrobial activity of new 6-phenylimidazo[2,1-b]thiazole derivatives.

A series of new N2-substituted-6-phenylimidazo[2,1-b]thiazole-3-acetic acid hydrazides (2a-j) were synthesized and evaluated for in vitro antimicrobial activity against various bacteria and fungi. Some of the compounds showed antimicrobial activity against Staphylococcus aureus ATCC 6538, Staphylococcus epidermidis ATCC 12228, Trichophyton mentagrophytes var. Erinacei NCPF-375, Trichophyton rubrum and Microsporum audounii (MIC 25-0.24 micrograms/ml). The in vitro antimycobacterial activity of the new compounds was also investigated. The compounds exhibited different degrees of inhibition (17.98%) against Mycobacterium tuberculosis H37Rv in the primary screen that was conducted at 12.5 micrograms/ml using the BACTEC 460 radiometric system.

Anti-Bacterial Agents↗
PubMed2000

[Clinical application of reticulated platelet analysis using the matic-modified thiazole orange method and flow cytometry].

Reticulated platelet (RP) analysis using thiazole orange (TO) and a flow cytometer is a convenient and promising method for estimating platelet kinetics in patients with thrombocytopenia. Among many different modifications of the TO method, a novel protocol reported by Matic in 1998 seems to be superior because it allows RP analysis using a sample of whole blood very quickly and accurately. Therefore, we used this method to analyze platelet kinetics in patients with idiopathic thrombocytopenic purpura (ITP) and hemophagocytic syndrome (HPS), as well as patients with hematopoietic malignancies (HM) after intensive chemotherapy. The proportion of RP was increased in the patients with ITP and HPS, and furthermore showed a negative linear correlation with the platelet count. The change in the proportion of RP occurred about one week before the change in the circulating platelet count in the patients with HM after chemotherapy. This modification of the TO method by Matic is expected to become a standard protocol for RP analysis.

Adult↗
PubMed1976

[Phthalimide derivatives of pyrimidine and thiazole heterocyclics].

The synthesis of some phthalimido-derivatives of the pyrimidine and thiazole ring systems is described. The functional groups have been suitably selected to enhance structural analogy with the pairs of pyrimidine and purine bases present in nucleic acids. In preliminary tests some of these compounds have shown inhibitory activity towards RNA polymerase reaction in vitro.

DNA-Directed RNA Polymerases↗
PubMed2003

Synthesis of some new thiazole derivatives of pharmaceutical interest.

Reaction of 4-amino-3-phenyl-5-ethoxycarbonyl-thiazole-2-thione with phenylisothiocyanate gave (2) which when boiled with acetic acid gave (3). Treatment of (2) with monochloroacetic acid resulted in the formation of thiazolidinone derivative (4). Reaction of (2) with malonic acid gave (5). Condensation of (1) with aromatic aldehydes afforded Schiffe base derivatives (6a,b). Treatment of (1) with malononitrile, ethyl cyanoacetate and acetonitrile resulted the formation of pyridine derivatives (7a,b,c). The reaction of (1) with urea and thiourea gave compound (8). Condensation of (1) with o-phenylenediamine and o-aminophenol gave compound (9). Reaction of (1) with nitrous acid followed by coupling with ethylacetoacetate afforded (10). Bromination of (10) gave bromo derivative (11). The structures of the hitherto unknown compounds have been confirmed by analytical and spectral methods. The newly synthesized compounds were screened for antibacterial activity.

Anti-Bacterial Agents↗
PubMedDate not supplied

Potential antitumor agents. 34.(1) Synthesis and antitumor activity of guanylhydrazones from imidazo[2,1-b]thiazoles and from diimidazo[1,2-a: 1,2-c] pyrimidine.

We report the synthesis of new guanylhydrazones from imidazo[2,1-b]thiazoles and of a bis-guanylhydrazone from diimidazo[1,2-a:1,2-c]pyrimidine. The compounds were tested as potential antitumor agents at the National Cancer Institute. Two derivatives are now under review by BEC: one of these was also subjected to a test for positive inotropic activity in view of a possible coanthracyclinic activity. Tyrosine kinase receptors may be involved as molecular targets in the mechanism of action of the guanylhydrazones described.

Antineoplastic Agents↗
PubMed1992

Nephrotoxicity of thiazoles structurally related to thiabendazole in mice depleted of glutathione by treatment with buthionine sulfoximine.

In mice depleted of glutathione (GSH) by treatment with DL-buthionine sulfoximine (BSO), thiabendazole [2-(4'-thiazolyl)benzimidazole, TBZ] produces renal damage characterized by increases in relative kidney weight and serum urea nitrogen (SUN) concentration. Several thiazole and benzimidazole compounds related to TBZ were examined for the ability to cause nephrotoxicity in mice pretreated with BSO. 4-Methyl- and 4-phenylthiazoles were highly effective compounds. In the absence of BSO, 4-methylthiazole resulted in no nephrotoxicity; inhibitors of hepatic and renal cytochrome P-450 enzymes such as methoxsalen and piperonyl butoxide prevented the nephrotoxicity of 4-methylthiazole given in combination with BSO. In addition, there was a sex difference in the nephrotoxicity of 4-methylthiazole in combination with BSO; the nephrotoxicity was observed only in males. These features of nephrotoxicity of 4-methylthiazole are well in accord with those of TBZ previously reported. This suggests that TBZ and 4-methylthiazole share a common mechanism of nephrotoxicity.

Animals↗
PubMed1990

Flow cytometric analysis of thiazole orange uptake by platelets: a diagnostic aid in the evaluation of thrombocytopenic disorders.

Thiazole orange (TO), a fluorescent dye originally synthesized for reticulocyte analysis, is characterized by a large fluorescence enhancement and high quantum yield on binding to nucleic acids, particularly RNA. In addition, the dye readily permeates live cell membranes. We applied TO staining, followed by fluorescence-activated flow cytometric analysis, to platelets in whole blood samples from hematologically normal subjects and patients with various quantitative platelet disorders. The percentage of TO-positive platelets in 50 control subjects was 8.6 +/- 2.8% (mean +/- SD) ranging from 2.8% to 15.8%. In 21 thrombocytopenic patients whose bone marrow contained normal to increased numbers of megakaryocytes, the percentage of fluorescently labeled platelets was significantly elevated (P less than .0001) to 26.9 +/- 10.9% (range, 13.3% to 57.1%). In contrast, the proportion of positively stained platelets in 23 patients with thrombocytopenia due to impaired platelet production (various conditions with reduced marrow megakaryocytes) did not significantly differ from the controls, whereas the absolute counts of TO-positive platelets were significantly lowered (P less than .0001). Differences in the distributions of the percentage values as well as of the absolute counts for TO-positive platelets between the two patient groups were again highly significant (P less than .0001). Both the sensitivity and the specificity of this method in distinguishing between these categories of thrombocytopenia were greater than or equal to 95%. We conclude that flow cytometric analysis of platelets after staining with TO is a sensitive and specific test that rapidly provides information on the thrombopoietic activity in thrombocytopenic disorders. Our data further suggest that increased amounts of residual RNA characterize platelets released under conditions of "stress thrombopoiesis."

Benzothiazoles↗
PubMed1991

[Lethal activity of benzamido-2 nitro-5 thiazole and its derivatives against Lymnaea peregra ovata Müller (Mollusca: Pulmonata) and Gammarus pulex pulex L. (Crustacea: Amphipoda)].

The toxicity of benzamido-2-nitro-5-thiazole (BNT) and 3 derivatives was studied on Lymnaea peregra ovata and Gammarus pulex pulex. These results were compared with the toxicity obtained by application of a basic product, niclosamide. The evaluation of LC50 (50% lethality concentration) was studied to evaluate the toxicity of each product after 4 different assay periods: 24, 48, 72 and 96 h. The compounds had a high toxicity against snails. Molluscicidal effect was higher than the lethal activity against Crustacea. The ortho substitution decreased the toxicity of products compared with BNT.

Animals↗
PubMedDate not supplied

[PAF-acether antagonistic pyrrolo[1,2-c]thiazoles: from RP 48740 to RP 59227].

The optimisation of the PAF antagonistic activity of RP 48740 led to the discovery of still more potent molecules of the pyrrolo[1,2-c]thiazole family: RP 52629, RP 52770 and RP 59227. The latter compound, for which a stereo-specific synthesis was developed, exhibits a very high potency as a PAF receptor antagonist.

Animals↗
PubMed1989

Immunomodulation by the new synthetic thiazole derivative tiprotimod. 3rd communication: influence on host resistance to microorganisms, tumors and on experimental immune disorders.

To evaluate the influence of [2-(3-carboxy-1-probylthio)-4-methyl-1,3-thiazole]acetic acid (tiprotimod, HBW 538) on the host defense mechanisms, a number of experimental studies in different animal models were performed. The prophylactic treatment of NMRI mice with tiprotimod significantly prolonged the mean survival time of the animals after intravenous infection with Candida albicans 200/175 and increased the resistance to the fungal infection to 180% in comparison to controls. In vitro the drug showed no direct fungistatic or fungicidal activity. In an experimental model of persistent systemic candidiasis Balb/c mice infected intravenously with Candida albicans were treated with the immunomodulator tiprotimod after the fungal colonization of kidney was manifested (3 days post infection). The treatment of the mice after the infection resulted in a reduction of the infectious load and the abscess formation in kidney as well as in a decrease of numbers of yeasts in the urine. In the syngeneic B16 melanoma tumor model tiprotimod significantly prolonged the medium survival time and reduced the number of visuable metastases in the lungs even when applied after resection of the primary tumor graft. Tiprotimod also beneficially influenced the course of the disease in two murine graft-vs-host models (hemolytic anemia and immune complex glomerulonephritis) which lead to a B cell mediated autoimmune disease with fatal outcome. The application of the drug in the induction phase mitigated the development of the diseases and prevented animals from dying.(ABSTRACT TRUNCATED AT 250 WORDS)

Adjuvants, Immunologic↗
PubMed1985

[C-2 basically substituted thiazoles with H2-antagonistic action. 21. H2-antihistaminics].

In studies on structure-activity relationships of histamine H2-receptor antagonists, C-2 basically substituted thiazoles were prepared and tested for their H2-antihistaminic activity on the isolated guinea-pig atrium and on the histamine stimulated acid secretion of the anaesthetized rat. As a basic substituent the dimethylaminomethyl group is especially suitable, while cyclic guanidines lead to lower H2-antagonistic activity.

Animals↗