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PubMed1988

Lack of initiating and promoting activity of thiourea in rat liver foci bioassay.

Thiourea (TU) fails to enhance the incidence of foci deficient in adenosine-5'-triphosphatase (ATPase) either by initiation or by promotion in a rat liver foci bioassay. To weanling female Sprague-Dawley rats, 3 x 200 or 3 x 500 mg/kg body wt of TU, respectively, were applied for initiation. One week later Clophen A 50, a technical mixture of polychlorinated biphenyls (PCBs) 2 x 10 mg/kg body wt were given twice weekly as promoting agent for 11 weeks. For promotion 0.2% of TU was administered with the drinking water for 51 days to rats of both sexes, and 0.1% and 0.05% of TU, respectively, for 70 days to females after initiation with 1 x 8 mg/kg body wt of diethylnitrosamine (DEN).

Animals↗
PubMed1994

Synergistic effects of phenobarbital and thiourea on proliferative lesions in the rat liver.

To evaluate the effects of phenobarbital (PB) and thiourea (TU), alone or in combination, on proliferative lesions of the liver, thyroid and lung, male F344 rats initiated with 2000 mg/kg body weight N-bis(2-hydroxypropyl) nitrosamine (DHPN) were given diet and/or drinking water containing 0% PB/TU (group 1), 1000 ppm PB (group 2), 0.1% TU (group 3) and 500 ppm PB and 0.05% TU (group 4), from weeks 2 to 20 for 19 weeks. Group 4 showed remarkable increases in the number of hepatocellular altered foci per animal, the values being superior to the averages of groups 2 and 3. The number of thyroid proliferative lesions per animal was highest in group 3 and lowest in group 2. Lung proliferative lesions were induced in all groups, but no modifying influence on their development was evident in the combined group. The present results indicate that combined administration of PB and TU exerts synergistic enhancing effects on hepatocarcinogenesis.

Animals↗
PubMed1994

Time course observation of thyroid proliferative lesions and serum TSH levels in rats treated with thiourea after DHPN initiation.

Time course changes in serum TSH and quantitative data for thyroid proliferative lesions in male F344 rats administered N-bis(2-hydroxypropyl)nitrosamine (DHPN: 2000 mg/kg body weight, single s.c. injection) followed by 0.1% thiourea (TU), were assessed at weeks 1, 2, 4, 8, 12 and 16 of treatment. The serum T4 level in the TU group was markedly decreased at week 1 and remained significantly lowered throughout the experiment. Serum TSH levels, in contrast, were elevated up to a peak at around week 4 with a return to the normal range at week 12. Thyroid weights in the TU group were increased significantly in a treatment period-dependent manner. Histopathologically, marked hypertrophy of thyroid follicular cells occurred at the early stage of TU treatment. Proliferative lesions, such as hyperplasia and adenomas, occurred from weeks 2 and 4, respectively, and increased with the later treatment period. The cell proliferative activity of follicular cells, assessed by BrdU incorporation, was high until week 2, but then returned to normal. The initially appearing hyperplasias and adenomas were characterized by marked proliferation but this also greatly decreased at later stages when TSH was no longer elevated. The results of our study thus suggest that a high serum TSH level plays an important role in the early phase of thyroid tumorigenesis and 8 weeks treatment with test substances is sufficient for detection of thyroid tumor promoter potential in two-stage thyroid carcinogenesis models.

Adenoma↗
PubMed1996

Promoting effect of large amounts of vitamin A on cell proliferation of thyroid proliferative lesions induced by simultaneous treatment with thiourea.

In order to examine modifying effects of simultaneous treatment with large amounts of vitamin A (VA) and thiourea (TU) on the thyroid tumorigenesis in rats, male F344 rats were initiated with N-bis(2-hydroxypropyl)nitrosamine (2800 mg/kg body weight, single s.c. injection), and starting 1 week later received diet containing 0.1% VA (VA group), drinking water containing 0.2% TU (TU group), 0.2% TU + 0.1% VA (TU + VA group) or tap water/basal diet (control group) for 19 weeks. Serum T3 and T4 in the TU and TU + VA groups were significantly decreased as compared to the control group, while serum TSH levels were remarkably increased. The ratios of T3 and T4 decrease and TSH increase in the TU + VA group were remarkably more pronounced than in the TU group. Thyroid neoplastic lesions were only induced in the TU and TU + VA groups. The multiplicity of intracapsular follicular cell proliferative foci in the TU + VA group was significantly increased as compared to the TU group value. Cell proliferation of hypertrophic and subcapsular follicular cells, as well as in hyperplasias, and neoplasias with adenomatous growth pattern was significantly higher in the combined treatment case than after TU alone. In the liver, centrilobular hypertrophy of hepatocytes was seen in the TU and TU + VA groups, this being especially marked in the latter group. In the combined group case the affected cells were strongly positive for GST-P antibody binding. The results of the present study suggest that cell proliferation of thyroid follicular cell proliferative lesions in rats is enhanced by strong TSH stimulation with simultaneous treatment of TU and large amounts of VA.

Adenoma↗
PubMed1990

Non-enzymatic covalent binding of radioactivity from [14C]thiourea to rat lung protein.

In vitro covalent binding of radioactivity from [14C]thiourea (TU) to rat lung protein occurs in the presence of 100% CO2. Prior boiling of lung slices results in a subsequent increase in covalent binding. Covalently bound radioactivity was released from rat lung homogenates and acid-insoluble protein obtained from animals treated with [14C]TU. The release was achieved with ammonium ion. One possibility suggested by these results is that the bound species may involve binding of isothiocyanic acid via a thiocarbamylation reaction.

Acetates↗
PubMed1991

Effects of thiourea on pulmonary vascular permeability and on lung and plasma histamine levels in rats.

The intraperitoneal administration of thiourea (TU) to mature male rats results in a significant increase in lung vascular permeability to Evans Blue dye (EBD). On the other hand, young, sexually immature rats are resistant to this effect. The increase in lung vascular permeability in response to TU in mature rats is associated with corresponding increases in lung and plasma histamine levels. The correlation of increases in lung and plasma histamine in response to TU is similar to that reported for ammonium salts which produce similar pulmonary edema.

Age Factors↗
PubMed2004

N-[4-(methylsulfonylamino)benzyl]thiourea analogues as vanilloid receptor antagonists: analysis of structure-activity relationships for the "C-Region".

We recently reported that N-(4-t-butylbenzyl)-N'-[4-(methylsulfonylamino)benzyl] thiourea (2) was a high affinity antagonist of the vanilloid receptor with a binding affinity of K(i)=63 nM and an antagonism of K(i)=53.9 nM in rat VR1 heterologously expressed in Chinese hamster ovary (CHO) cells (Mol. Pharmacol. 2002, 62, 947-956). In an effort to further improve binding affinity and antagonistic potency, we have modified the C-region of the lead 4-t-butylbenzyl group with diverse surrogates, such as araalkyl, alkyl, 4-alkynylbenzyl, indanyl, 3,3-diarylpropyl, 4-alkoxybenzyl, 4-substituted piperazine and piperidine. The lipophilic surrogates, arylalkyl and alkyl, conferred modest decreases in binding affinities and antagonistic potencies; the groups having heteroatoms resulted in dramatic decreases. Our findings indicate that 4-t-butylbenzyl is one of the most favorable groups for high receptor binding and potent antagonism to VR1 in this structural series.

Animals↗
PubMed2004

Analysis of structure-activity relationships with the N-(3-acyloxy-2-benzylpropyl)-N'-[4-(methylsulfonylamino)benzyl]thiourea template for vanilloid receptor 1 antagonism.

In a continuing effort to elucidate the structure-activity relationships of the lead antagonist N-[2-(3,4-dimethylbenzyl)-3-pivaloyloxypropyl]-N'-[4-(methylsulfonylamino)benzyl]thiourea (1), the distances between the proposed four pharmacophores in 1 have been varied by insertion or deletion of one carbon to optimize their fit to the receptor. In addition, the acyloxy group of the C region was replaced with amide and N-hydroxy amide to identify the pharmacophoric importance of the ester group in the C2 region. The results indicated that the pharmacophoric arrangement of 1 was optimal for receptor binding affinity and antagonism, and the ester of the C2 region was significant for receptor binding. Among the derivatives, compound 19 showed distinct behavior with a 2-fold improvement in antagonism but a 13-fold reduction in binding affinity compared to 1. The partial separation of pharmacophoric requirements of these two assays has been noted before and compound 19 is thus selective for the calcium entry-linked receptor population. The conformational analysis of 1 generated three distinct conformers having different types of hydrophobic interactions, which will be utilized for exploring the active conformation of the VR1 ligand.

Amides↗
PubMed2004

Synthesis of tetrahydronaphthyl thioureas as potent appetite suppressants.

A series of thiourea derivatives (7-23, 25-27) of 1-aminotetrahydronaphthalene (4) and 1-amino-2-hydroxytetrahydronaphthalene (5) were synthesized in single pot in 48-90% yield and evaluated for their anorexigenic activity. Among them compounds 10, 14, 15, 16 and 22 exhibited significant anorexigenic activity without any antidepressant effect and provided a new structural lead for appetite suppressants.

Animals↗
PubMed2004

N-4-Substituted-benzyl-N'-tert-butylbenzyl thioureas as vanilloid receptor ligands: investigation on the role of methanesulfonamido group in antagonistic activity.

A series of N-4-substituted-benzyl-N'-tert-butylbenzyl thioureas were prepared for the study of their agonistic/antagonistic activities to the vanilloid receptor in rat DRG neurons. Their structure-activity relationship reveals that not only the two oxygens and amide hydrogen of sulfonamido group, but also the optimal size of methyl in methanesulfonamido group play an integral role for the antagonistic activity on vanilloid receptor.

Animals↗
PubMed2004

N-4-methansulfonamidobenzyl-N'-2-substituted-4-tert-butyl-benzyl thioureas as potent vanilloid receptor antagonistic ligands.

A series of N-4-methansulfonamidobenzyl-N'-2-substituted-4-tert-butylbenzyl thioureas were prepared for the study of their agonistic/antagonistic activities to the vanilloid receptor in rat DRG neurons. Their structure-activity relationship reveals that there is a space for another hydrophobic binding interaction around 2-position in 4-tert-butylbenzyl region. Among the prepared derivatives, 6n show the highest antagonistic activity against the vanilloid receptor (IC(50)=15 nM).

Animals↗
PubMed2006

Synthesis of 1-[3-(4-benzotriazol-1/2-yl-3-fluoro-phenyl)-2-oxo-oxazolidin-5-ylmethyl]-3-substituted-thiourea derivatives as antituberculosis agents.

In continuation of our research program for new antituberculosis drugs, we have designed, synthesized and evaluated antimycobacterial activity of new series of 1-[3-(4-benzotriazol-1/2-yl-3-fluoro-phenyl)-2-oxo-oxazolidin-5-ylmethyl]-3-substituted-thiourea derivatives against different Mycobacterium species i.e. M. tuberculosis, M. avium and M. intracellulare in an agar dilution method. Compound 17 exhibited excellent antimycobacterial activity (in vitro) against drug sensitive and resistant clinical isolates of M. tuberculosis. Its MIC value is equivalent to linezolid and superior to isoniazid against all these strains.

Antitubercular Agents↗
PubMed2005

Cyclization of the substituted N-(ortho-cyclopropylphenyl)-N'-aryl ureas and thioureas in the gas phase and solution.

Electron ionization (EI), chemical ionization (CI), tandem mass spectrometry, high-resolution measurements, and labeling studies as well as quantum chemical calculations were used to understand the behavior of the molecular radical cations (EI) and protonated molecules (CI) of substituted N-(ortho-cyclopropylphenyl)-N'-aryl ureas and N-(ortho-cyclopropylphenyl)-N'-aryl thioureas in a mass spectrometer. Fragmentation schemes and possible mechanisms of primary isomerization were proposed. According to the fragmentation pattern, formation of the corresponding benzoxazines and benzothiazines was considered as the major process of isomerization of the original M(+.) and MH(+), although some portions of these ions definitely transformed into other structures. The treatment of N-(ortho-cyclopropylphenyl)-N'-phenyl urea and N-(ortho-cyclopropylphenyl)-N'-phenylthiourea in solution with strong acids formed predicted 4-ethyl-N-phenyl-4H-3,1-benzoxazin-2-amin and 4-ethyl-N-phenyl-4H-3,1-benzothiazin-2-amine as principal products.

Algorithms↗
PubMed2005

Thiourea, triazole and thiadiazine compounds and their metal complexes as antifungal agents.

Many currently available antifungal and antibacterial agents have undesirable toxic effects, and a wide spread use of these drugs has lead to rapid development of drug resistant strains which are the leading cause for treatment failure in both clinical and agricultural applications. The present article provides a synopsis of recent progress in investigations of new classes of antifungal compounds: disubstituted aliphatic and aromatic thioureas, triazole and thiazine compounds which act as ligands for transition metals. Antifungal effects of these compounds and selected metallic complexes versus representative plant pathogenic fungi are reviewed.

Anti-Bacterial Agents↗