biochem.uni-kiel.de

OBJECTIVE: Evaluation of tetracycline effects on the expression of MMP-1, MMP-3, tissue inhibitor(s) of metalloproteinase-1 (TIMP-1), plasminogen activators (PA), and PA inhibitor-1, which are all involved in the ultimate regulation of MMP activity could provide new insight into how tetracyclines achieve their cartilage preserving effects. MATERIALS AND METHODS: We used bovine articular chondrocytes cultured in alginate gel beads for our studies which were initially treated with 10 microM tetracyclines in the presence of IL-1. Only significant effects were studied at additional concentrations. Expression of mRNA was analyzed by RT-PCR-ELISA. The activity of enzymes and TIMP was measured by functional assays; whereas, the level of PAI-1 was determined by ELISA. RESULTS: Treating chondrocytes with IL-1 induced the expression of MMPs and downregulated TIMP-1 but stimulated both the expression of PAs and PAI-1. When tested at 10 microM only minocycline reduced collagenase activity and expression of MMP-1. Further pharmacokinetic analysis revealed IC50 values of 26 microM and 16 microM for the inhibition of collagenase activity and mRNA expression, respectively. Production of MMP-3 was only decreased by tetracycline (IC50 = 45.4 microM). No effects of tetracyclines could be observed on proteoglycan degradation, TIMP activity and the production of PAs, PAI-1, and TIMP-1. CONCLUSIONS: We conclude that the inhibition of MMPs by tetracyclines occurs mainly via down-regulation of the respective gene expression.

Source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11339506&dopt=Abstract antibiotics, tetracycline

tiho-hannover.de

Little is known about the occurrence and the fate of veterinary drugs in the environment. Therefore, a liquid chromatography/tandem mass spectrometry method was developed and employed to investigate in detail the distribution and persistence of the frequently used tetracyclines and tylosin in a field fertilized with liquid manure on April 2000 and April 2001; soil sampling was performed in May 2000, November 2000, and May 2001. We detected 4.0 mg/kg tetracycline and 0.1 mg/kg chlortetracycline in the liquid manure of April 2000, as well as comparable amounts in the liquid manure of April 2001. In the soil samples of May 2001, the highest average concentrations of 86.2 (0-10 cm), 198.7 (10-20 cm), and 171.7 microg/kg (20-30 cm) tetracycline and 4.6-7.3 micro/kg chlortetracycline (all three sublayers) were found. At soil depths between 30 and 90 cm, as well as in soil or groundwater, tetracyclines could not be detected. In addition, oxytetracycline and tylosin could not be detected in any sample investigated. We conclude that tetracyclines enter the environment in significant concentrations via repeated fertilizations with liquid manure, build up persistent residues, and accumulate in soil. Therefore, tetracyclines may have a potential risk and investigations on the environmental effects of these antibiotics are necessary.

Source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12033238&dopt=Abstract antibiotics, tetracycline




Antibiotiki. 1976 Feb;21(2):130-4.
[Tetracycline resistance and cell-free systems of protein and polypeptide synthesis]

[Article in Russian]

Beliavskaia IV, Kukhanova MK, Griaznova NS, Sazykin Iu, Nevashin SM.

Acellular systems of synthesis of polyphenylalanin containing the supernatant fraction from E. coli B and ribosomes from an oxytetracycline sensitive strain of E. coli and strains resistant to that antibiotic were almost equally sensitive to oxytetracycline. The supernatant fraction from the cells of E. coli 241, a resistant strain absorbing significant amounts of oxytetracycline lowered the inhibiting effect of oxytetracycline in the acellular systems of protein synthesis (with an endogenic matrix). No fermentative inactivation of oxytetracycline by that fraction was found with both the biological and radiochromatographic methods.

Source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=776071&dopt=Abstract antibiotics, tetracycline




J Pharm Biomed Anal. 2003 Sep 15;33(1):85-93.
Assay and purity control of tetracycline, chlortetracycline and oxytetracycline in animal feeds and premixes by TLC densitometry with fluorescence detection.

Naidong W, Hua S, Roets E, Hoogmartens J.

Laboratorium voor Farmaceutische Chemie en Analyse van Geneesmiddelen, Faculteit Farmaceutische Wetenschappen, Katholieke Universiteit Leuven, Van Evenstraat 4, B-3000 Leuven, Belgium.

Methods using TLC densitometry with fluorescence detection are described for the assay and purity control of tetracycline (TC), chlortetracycline (CTC), and oxytetracycline (OTC) in animal feeds and premixes. With a silica gel layer previously sprayed with 10% (m/v) sodium EDTA solution adjusted to pH 8.0 or 9.0, all the major impurities were separated from the main components and from each other. The mobile phase consisted of dichloromethane, methanol, and water. After development, the plate was dipped in a 30% (v/v) solution of liquid paraffin in hexane. Quantitation was realized by fluorescence densitometry at 400 nm. The limit of quantitation (LOQ) for tetracycline impurities is 0.8 microg/g, corresponding to 0.2% of the label claimed tetracycline (400 microg/g). The LOQ for impurities of tetracycline and chlortetracycline in premixes is 0.2% of the label-claimed TC (40 mg/g) and CTC (200 or 400 mg/g). The LOQ for impurities of oxytetracycline in a premix is 0.1% of the label claimed OTC (100 mg/g).

Source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12946534&dopt=Abstract antibiotics, tetracycline

med.monash.edu.au

The Clostridium perfringens tetracycline resistance protein, TetA(P), is an inner-membrane protein that mediates the active efflux of tetracycline from the bacterial cell. This protein comprises 420 aa and is predicted to have 12 transmembrane domains (TMDs). Comparison of the TetA(P) amino acid sequence to that of several members of the major facilitator superfamily (MFS) identified a variant copy of the conserved Motif A. This region consists of the sequence E59xPxxxxxDxxxRK72 and is located within the putative loop joining TMDs 2 and 3 in the predicted structural model of the TetA(P) protein. To study the functional importance of the conserved residues, site-directed mutagenesis was used to construct 17 point mutations that were then analysed for their effect on tetracycline resistance and their ability to produce an immunoreactive TetA(P) protein. Changes to the conserved Phe-58 residue were tolerated, whereas three independent substitutions of Pro-61 abolished tetracycline resistance. Examination of the basic residues showed that Arg-71 is required for function, whereas tetracycline resistance was retained when Lys-72 was substituted with arginine. These results confirm that the region encoding this motif is important for tetracycline resistance and represents a distant version of the Motif A region found in other efflux proteins and members of the MFS family. In addition, it was shown that Glu-117 of the TetA(P) protein, which is predicted to be located in TMD4, is important for resistance although a derivative with an aspartate residue at this position is also functional.

Source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=14702405&dopt=Abstract [PubMed - in process]

Ugent.be

Four methods intended for screening muscle tissue for residues belonging to the tetracycline group were compared using artificially contaminated as well as incurred samples. Two agar diffusion methods were studied: one with Bacillus subtilis as a test strain, the second with Bacillus cereus. Two variants of each method were compared: thin plates for analysis of intact or minced meat, and thick plates for analysis of meat fluid. The thin plate variants could not be evaluated with artificially contaminated samples because it was impossible to prepare homogeneously spiked, undiluted meat. The thick plates were suited for doxycycline and chlortetracycline, but they did not detect oxytetracycline or tetracycline in spiked meat fluid. The results of these tests done on incurred meat were very good for doxycycline and satisfying or just failing for oxytetracycline, while the best detection capability was obtained when intact frozen meat was examined on thin plates seeded with B. cereus. Two commercially available screening tests were also evaluated. The Premi(R) test, an inhibitor test with Bacillus stearothermophilus as a test strain and an indicator for growth, was not suited for detection of tetracyclines up to the maximum residue limit. Tetrasensor(R), a receptor test specific for tetracyclines, proved a quick and simple test able to detect meat samples artificially contaminated with tetracycline, oxytetracycline, doxycycline or chlortetracycline, as well as meat incurred with oxytetracycline or doxycycline.

Source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=14754636&dopt=Abstract [PubMed - in process]




Revmatologiia (Mosk). 1990 Jan-Mar;(1):17-21.
[The effect of tetracycline therapy on the laboratory indices of chlamydia infection in Reiter's disease (preliminary report)]

[Article in Russian]

Khamraev AA, Pankratova VN, Brodinova NS, Orlova OE, Shubin SV.

The authors studied the effect of tetracycline therapy (short and long courses) on the indices of chlamydia infection (antigens and antibodies) in Reiter's urogenous disease. The concentration of tetracycline in the blood serum and synovial fluid when administered in a daily dose of 2.0 g (single dose 0.5 g) was determined. It has been established that tetracycline exerts an inhibitory effect on the chlamydia infection not in all the patients suffering from Reiter's disease despite sufficient concentration of the antibiotic in biological fluids (blood serum, synovial fluid). Prolonged courses of tetracycline therapy proved most effective.

Source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=2377858&dopt=Abstract antibiotics, tetracycline




J Endod. 1989 Aug;15(8):335-8.
Further characterization of tetracycline's quantitative binding to dentin.

Ciarlone AE, Johnson RD, Pashley DH.

Unerupted human third molar crown segments were used to measure the change in the concentration of 3H-tetracycline that occurs when it moves across dentin from pulpal to occlusal surfaces. When 1.25, 2.5, and 5 x 10(-5) M 3H-tetracycline were filtered across dentin, binding increased by 21, 51, and 69%, respectively. When the same concentrations of 3H-tetracycline were preloaded onto crown segments and eluted with 1.1 x 10(-3) M nonradioactive tetracycline, the percentage of elution of 3H-tetracycline was not significantly different over time. When preloaded 3H-tetracycline was displaced by diffusion with water or 1.1 x 10(-3) M nonradioactive tetracycline, there were no significant differences. There was a significant difference between the rate of displacement of 1.25 x 10(-5) M 3H-tetracycline and the other two preloaded concentrations when 5.8 x 10(-4) M 3H-tetracycline/tetracycline was used as the eluant. These data suggest that the binding of 3H-tetracycline to dentin was concentration dependent and that 3H-tetracycline binds nonspecifically and reversibly.

Source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=2637323&dopt=Abstract antibiotics, tetracycline