Biodegradation of cyclohexylamine by Brevibacterium oxydans IH-35A. (1/124)

A bacterial strain capable of growing on cyclohexylamine (CHAM) was isolated by using enrichment and isolation techniques. The strain isolated, strain IH-35A, was classified as a member of the genus Brevibacterium. The results of growth and enzyme studies are consistent with degradation of CHAM via cyclohexanone (CHnone), 6-hexanolactone, 6-hydroxyhexanoate, and adipate. Cell extracts obtained from this strain grown on CHAM contained CHAM oxidase, and the model for CHAM oxidation by this enzyme was similar to the model for deamino oxidation of amine by amine oxidase.  (+info)

Anti-tumour activity of tachykinin NK1 receptor antagonists on human glioma U373 MG xenograft. (2/124)

Astrocytes harbour functional receptors to many neurotransmitters, including substance P (SP), an undecapeptide belonging to the tachykinin family of peptide transmitters. SP activates malignant glial cells to induce cytokine release and proliferation, both responses being relevant for tumour progression. In tumours developed in nude mice transplanted subcutaneously (s.c.) to U373 MG human glioma cells, the presence of SP was observed at immunohistochemistry. Although the administration of exogenous SP did not significantly affect the size or development of U373 MG xenograft, a role of SP in supporting glioma progression in vivo was highlighted by the tumour growth inhibition induced by highly specific and selective human tachykinin NK1 receptor antagonists (MEN 11467 and MEN 11149). The anti-tumour activity of MEN 11467 was observed both with s.c. or intravenous treatments and was partially reverted by the concomitant administration of exogenous SP. Doxorubicin did not show any activity in controlling U373 MG growth in this in vivo model. A novel therapeutic approach to treat malignant gliomas with tachykinin NK1 receptor antagonists is suggested by these findings.  (+info)

Long-term toxicity and carcinogenicity study of cyclamate in nonhuman primates. (3/124)

Twenty-one monkeys (cynomolgus, rhesus, African green) were fed cyclamate (100 mg/kg and 500 mg/kg) in the diet five times per week from a few days after birth and continuing for up to 24 years. Malignant tumors were diagnosed in three 24-year-old cyclamate monkeys; these were metastatic colon carcinoma (rhesus; 500 mg/kg), metastatic hepatocellular carcinoma (cynomolgus; 500 mg/kg), and a small, well differentiated adenocarcinoma of the prostate (cynomolgus; 100 mg/kg). Benign tumors were found at necropsy in three females; these were adenoma of the thyroid gland (rhesus; 100 mg/kg) and two cases of leiomyoma of the uterus (rhesus; 100 mg/kg and 500 mg/kg). No tumors were detected in an age-matched control group of 16 monkeys. Examination of the testes revealed complete testicular atrophy in one of the old cyclamate monkeys, and focal germ cell aplasia (Sertoli-only tubules) in two other cyclamate monkeys. Focal spermatogenic interruption (maturation arrest) at various germ cell levels mixed with normal spermatogenesis was observed in both the cyclamate-treated and the control monkeys, all of which were over 20 years old. Measurements of terminal cyclohexylamine concentrations showed that three of the males dosed with cyclamate at 500 mg/kg were high converters, with plasma concentrations comparable to the levels that produce testicular atrophy in rats. However, only one of the three high converters showed histologic evidence of irregular spermatogenesis. The overall conclusion is that the testicular abnormalities and the sporadic cases of different malignancies found after more than 20 years of dosing do not provide clear evidence of a toxic or carcinogenic effect of sodium cyclamate in monkeys.  (+info)

Effect of insulin on protein turnover in heart muscle. (4/124)

The effect of insulin on turnover of protein was investigated in isolated perfused rat hearts. The hormone lowered intracellular levels of nine amino acids and reduced or abolished net release of 10 amino acids and ammonia. The extent of the insulin effect on protein degradation was investigated by estimating the rate of dilution of the specific radioactivity of the free phenylalanine pool. Insulin concentrations greater than 200 microunits per ml reduced protein degradation and net phenlylalanine release. Protein degradation was estimated more directly by inhibiting reincorporation of nonradioactive phenylalanine from protein with cycloheximide. Addition of the inhibitor increased the estimated rates about 50%, but the magnitude of the hormone effect was similar. The latency of lysosomal enzymes in control and insulin-treated hearts was assessed by measuring activities of beta-acetylglucosaminidase and cathepsin D in heart homogenates in the presence and absence of Triton X-100. Perfusion with insulin-free buffer increased the activities assayable without detergent, but did not change total activities of these enzymes. Insulin decreased activities assayable without detergent and increased activities sedimenting in the 10-5 times g pellet. These studies showed that insulin restricted the rate of protein degradation in the isolated perfused rat heart. Concomitantly, the latency of lysosomal enzymes was increased when the hormone was provided.  (+info)

Effect of the long-acting tachykinin NK(1) receptor antagonist MEN 11467 on tracheal mucus secretion in allergic ferrets. (5/124)

1. We investigated the effect of MEN 11467 ((1R,2S)-2-N[1(H)indol-3-yl-carbonyl]-1-N-[N(alpha)(p-tolylacetyl)-N(alpha)(methy l)-D-3-(2-naphthyl)alanyl]diaminocyclohexane) on tachykinin-induced mucus secretion in ferret trachea in vitro and determined its effect on secretion by tracheae from allergic ferrets in response to allergen challenge. 2. Repeated administration of [Sar(9),Met(O(2))(11)]-substance P ([Sar(9)]SP, 1 microM) maintained mucus output above control values for at least 1.75 h. MEN 11467 inhibited secretion in a concentration-dependent manner with maximal inhibition at 10 microM and an approximate IC(50) of 0.3 microM. Inhibition by MEN 11467 (0.1--10 microM) was maintained, to varying degree, for at least 1.75 h after washout in the continued presence of [Sar(9)]SP. 3. In electrically stimulated tracheae, tachykininergic neural secretion was virtually abolished by 1 microM MEN 11467. 4. In tracheae from ovalbumin-sensitised animals, repeated administration of ovalbumin maintained mucus output above controls for 1.5 h. MEN 11467 inhibited ovalbumin-induced secretion in a concentration-dependent manner, with complete inhibition at 1 microM. Inhibition by MEN 11467 (1 and 10 microM) was maintained, to varying degree, after drug washout for the 1.5 h of ovalbumin stimulation. 5. MEN 11467 1 microM did not affect secretion induced by either acetylcholine or histamine, whereas 10 microM MEN 11467 did inhibit agonist-induced secretion. 6. We conclude that, in ferret trachea in vitro, MEN 11467 at concentrations of 0.1--1 microM is a long acting and selective inhibitor of tachykininergic-induced mucus secretion, and may have therapeutic potential for bronchial hypersecretion associated with allergic conditions, for example in asthma.  (+info)

2-chloroethanol formation as evidence for a 2-chloroethyl alkylating intermediate during chemical degradation of 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea and 1-(2-chloroethyl)-3-(trans-4-methylcyclohexyl)-1-nitrosourea. (6/124)

Chemical degradation of 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea or 1-(2-chloroethyl)-3-(trans-4-methylcyclohexyl)-1-nitrosourea in buffer under physiological conditions resulted in the formation of a significant quantity of 2-chlorethanol (18 to 25% of the initial nitrosourea concentration). Other degradation products observed included acetaldehyde (5 to 10%), vinyl chloride (1 to 2%), ethylene (1 to 2%), and cyclohexylamine (32%), but not 1,3-dicyclohexylurea. The 2-chlorethyl moiety of 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea was trapped with halide ions, CI-, BR-, and I-, to form the corresponding dihaloethanes which were identified by gas chromatography-mass spectrometry techniques. High-pressure liquid chromatographic procedures were developed for the separation and quantiation of the nitrosoureas and many of their degradation products. It is postulated that a new mode of 1(2-chloreoethyl)-3-cyclohexyl-1-nitrosourea and 1-(2-chloroethyl)-3-(trans-4-methylcyclohexyl)-1-nitrosourea degradation can occur that is not the loss of the chloro group as chloride ion, but the loss of the N-3 hydrogen as a proton. Then the corresponding isocyanate and 2-chloroethyidiazene hydroxide are formed, with the latter intermidiate becoming an alkylating species, possibly in part as a 2-chloroethyl carbonium ion.  (+info)

In vitro and in vivo activities of aminoadamantane and aminoalkylcyclohexane derivatives against Trypanosoma brucei. (7/124)

We reported recently that the bloodstream form of the African trypanosome, Trypanosoma brucei, is sensitive to the anti-influenza virus drug rimantadine. In the present report we describe the trypanocidal properties of a further 62 aminoadamantane and aminoalkylcyclohexane derivatives. Seventeen of the compounds were found to be more active than rimantadine, with four inhibiting growth in vitro of T. brucei by >90% at concentrations of 1 microM. The most active derivative (1-adamantyl-4-amino-cyclohexane) was about 20 to 25 times more effective than rimantadine. We observed a correlation between structural features of the derivatives and their trypanocidal properties; hydrophobic substitutions to the adamantane or cyclohexane rings generally enhanced activity. As with rimantadine, the activity in vitro varied with the pH. T. brucei was more sensitive in an alkaline environment (including a normal bloodstream pH of 7.4) and less sensitive under acidic conditions. Tests for activity in vivo were carried out with a mouse model of infection with a virulent strain of T. brucei. Although the parasitemia was not eliminated, it could be transiently suppressed by >98% with the most active compounds tested. These results suggest that aminoadamantane derivatives could have potential as a new class of trypanocidal agents.  (+info)

B cells, BAFF/zTNF4, TACI, and systemic lupus erythematosus. (8/124)

B cells and B-cell/T-cell collaborations are instrumental in the pathophysiology of systemic lupus erythematosus (SLE). This commentary highlights in particular the newly discovered role of B-cell-activating factor (BAFF; also known as TALL-1, THANK, BlyS, and zTNF4) as a positive regulator of B-cell functions, such as B-cell activation and differentiation. Two members of the tumor necrosis factor(TNF)-receptor superfamily were recently identified as receptors for BAFF on B cells. The interaction between BAFF and its receptors may be important in the pathogenesis of lupus. Advances in our understanding of abnormalities in immune regulation in lupus might provide the opportunity to improve our current therapeutic approaches to this disorder.  (+info)

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