Antibiotiki. 1978 Mar;23(3):215-9.
[Effect of auxiliary substances on the bioavailability of tetracycline hydrochloride capsules (an in vitro study)]

[Article in Russian]

Grakovskaia LK, Nesterova LIa, Okhotnikova VF, Zak AF, Ermolova OB.

The rate of tetracycline hydrochloride transfer into solution from capsules containing different auxiliary substances was studied. It was shown that the dispersity level of tetracycline hydrochloride powder had no significant effect on the capsule disintegration and the rate of the antibiotic transfer into solution. The effect of the auxiliary substance composition on the capsule disintegration and the rate of the antibiotic dissolution was shown. The rate of tetracycline liberation from the capsules containing tetracycline hydrochloride without additives or the antibiotic in combination with 23 per cent of lactose was 4 to 6 times higher than that from the capsules with magnesium carbonate or calcium phosphate as the auxiliary substances.

Source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=637528&dopt=Abstract antibiotics, tetracycline




Proc Natl Acad Sci U S A. 1996 Dec 10;93(25):14446-51.
The purified Bacillus subtilis tetracycline efflux protein TetA(L) reconstitutes both tetracycline-cobalt/H+ and Na+(K+)/H+ exchange.

Cheng J, Hicks DB, Krulwich TA.

Department of Biochemistry, Mount Sinai School of Medicine, City University of New York, New York 10029, USA.

Recent work has suggested that the chromosomally encoded TetA(L) transporter of Bacillus subtilis, for which no physiological function had been shown earlier, not only confers resistance to low concentrations of tetracycline but is also a multifunctional antiporter protein that has dominant roles in both Na(+)- and K(+)-dependent pH homeostasis and in Na+ resistance during growth at alkaline pH. To rigorously test this hypothesis, TetA(L) has been purified with a hexahistidine tag at its C terminus and reconstituted into proteoliposomes. The TetA(L)-hexahistidine proteoliposomes exhibit high activities of tetracycline-cobalt/H+, Na+/ H+, and K+/H+ antiport in an assay in which an outwardly directed proton gradient is artificially imposed and solute uptake is monitored. Tetracycline uptake depends on the presence of cobalt and vice versa, with the cosubstrates being transported in a 1:1 ratio. Evidence for the electrogenicity of both tetracycline-cobalt/H+ and Na+/H+ antiports is presented. K+ and Li+ inhibit Na+ uptake, but there is little cross-inhibition between Na+ and tetracycline-cobalt uptake activities. The results strongly support the conclusion that TetA(L) is a multifunctional antiporter. They expand the roster of such porters to encompass one with a complex organic substrate and monovalent cation substrates that may have distinct binding domains, and provide the first functional reconstitution of a member of the 14-transmembrane segment transporter family.

Source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=8962071&dopt=Abstract antibiotics, tetracycline




Can J Microbiol. 1979 Jun;25(6):789-92.
Chlortetracycline and sulfonamide resistance of fecal bacteria in swine receiving medicated feed.

Welch B, Forsberg CW.

The fecal bacterial flora of swine receiving a ration supplemented with chlortetracycline, sulfamethazine, and penicillin was tested for resistance to chlortetracycline and sulfamethazine using anaerobic techniques and medium M-10. Approximately 15.5 and 1.4% of the flora grew in the presence of 25 and 100 microgram of tetracycline/mL, respectively. Higher numbers of bacteria grew in the presence of similar concentrations of sulfamethazine. Thirty-five chlortetracycline-resistant isolates were tentatively identified by genera. Nine different genera were identified, four of these were Gram-positive and five were Gram-negative. The most common genera isolated were Streptococcus and Eubacterium. This demonstrates that in the fecal flora of swine fed rations supplemented with chlortetra-cycline, a wide variety of bacterial genera can be resistant to this antibiotic.

Source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=476553&dopt=Abstract antibiotics, tetracycline




Mol Cell Biol. 1998 Aug;18(8):4418-25.
Tetracycline-regulated suppression of amber codons in mammalian cells.

Park HJ, RajBhandary UL.

Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.

As an approach to inducible suppression of nonsense mutations in mammalian cells, we described recently an amber suppression system in mammalian cells dependent on coexpression of Escherichia coli glutaminyl-tRNA synthetase (GlnRS) along with the E. coli glutamine-inserting amber suppressor tRNA. Here, we report on tetracycline-regulated expression of the E. coli GlnRS gene and, thereby, tetracycline-regulated suppression of amber codons in mammalian HeLa and COS-1 cells. The E. coli GlnRS coding sequence attached to a minimal mammalian cell promoter was placed downstream of seven tandem tetracycline operator sequences. Cotransfection of HeLa cell lines expressing a tetracycline transactivator protein, carrying a tetracycline repressor domain linked to part of a herpesvirus VP16 activation domain, with the E. coli GlnRS gene and the E. coli glutamine-inserting amber suppressor tRNA gene resulted in suppression of the amber codon in a reporter chloramphenicol acetyltransferase gene. The tetracycline transactivator-mediated expression of E. coli GlnRS was essentially completely blocked in HeLa or COS-1 cells grown in the presence of tetracycline. Concomitantly, both aminoacylation of the suppressor tRNA and suppression of the amber codon were reduced significantly in the presence of tetracycline.

Source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9671451&dopt=Abstract antibiotics, tetracycline




Zhonghua Bing Li Xue Za Zhi. 1998 Oct;27(5):328-32.
[A study on the tumor suppressing effect of a specific point mutant p53 minigene in the expression regulated model with a tetracycline-transactivative response promoter]

[Article in Chinese]

Xie J, Wu B, Fang W.

Department of Pathology, Beijing Medical University, Beijing 100083.

OBJECTIVE: To establish a tetracycline-regulated expression model and to determine and verify whether a specific point mutant type p53 minigene, containing an Arg-->Leu substitution at amino acid 172, possesses a suppressing effect on human lung cancer. METHODS: The tumor suppressing effects of inducing apoptosis and inhibition of the formation of G418 resistant colonies of the specific point mutated p53 minigene in a structural expression vector on a human cancer cell line PG with preexisting dominant negative p53 were preliminarily verified. Then the specific p53 minigene was sub-cloned into a tetracycline-transactivative controlled expression vector pBPSTR1 by gene recombination methods. Through LipofectaMINE, the vector was transfected into PG cells under the presence of tetracycline (1.0 mg/ml), and the transfectants were screened in the selecting medium containing 1.5 micrograms/ml puromycin, the p53 minigene expression and tumor suppressing effects were studied dynamically in presence/absence (1.0/0 mg/ml) of tetracycline. RESULTS: The specific mutant p53 minigenes had a stronger tumor suppressing effect than wild type p53 minigene on colony formation and transient expression could induce PG cell apoptosis (P < 0.05). The tetracycline transactivative p53 minigene-regulated transgene model was successfully established. When tetracycline was absent, a large amount of apoptosis cells in transgenic passage colonies could be detected. Therefore the tumor suppressing effects were further verified. CONCLUSION: The specific point mutant p53 minigene may be a good candidate for cancer gene therapy. The tetracycline transactivative response promoter was found to be a good regulator of down stream gene expression, this may be useful in future gene therapy.

Source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11245004&dopt=Abstract antibiotics, tetracycline




Br J Clin Pharmacol. 1983 Aug;16(2):127-32.
Some tetracycline drugs suppress mitogen-stimulated lymphocyte growth but others do not.

Potts RC, MacConnachie A, Brown RA, Gibbs JH, Robertson AJ, Hassan HA, Beck JS.

Eight tetracycline drugs were tested for inhibitory effect on phytohaemagglutinin (PHA) stimulated growth (measured by [3H]-TdR uptake) of peripheral blood mononuclear cells: at least 26 normal subjects were tested with each drug. Doxycycline reduced DNA synthesis appreciably at concentrations within and just above the therapeutic range of blood levels: it was the most potent inhibitor, but demeclocycline, methacycline and minocycline had similar, if less potent, effects. Tetracycline, oxytetracycline, chlortetracycline and clomocycline did not inhibit DNA synthesis of 3-day cultures even at concentrations five to ten times greater than the therapeutic blood level. Volume spectroscopy measurements showed that none of the eight tetracycline drugs interfered with the recruitment of cells into G1-phase growth of the first cell cycle after PHA stimulation.

Source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=6615686&dopt=Abstract antibiotics, tetracycline




Quintessence Int. 1997 Feb;28(2):93-7.
Nondiseased dentinal root surface following citric acid or tetracycline hydrochloride conditioning: a scanning electron microscopic study on the effects of ultrasonic irrigation before and after root conditioning.

Babay N.

Preventive Dental Sciences Department, College of Dentistry, King Saud University, Riyadh, Saudi Arabia.

The scanning electron microscope was used to evaluate the effects of ultrasonic irrigation before and after root conditioning. Six groups of five specimens each received saline irrigation; ultrasonic irrigation; saline irrigation followed by root conditioning with either citric acid or tetracycline hydrochloride; or ultrasonic irrigation followed by root conditioning with either citric acid or tetracycline hydrochloride. After immersion in citric acid or tetracycline hydrochloride solutions, root dentin was rinsed again with saline or irrigated ultrasonically. Control specimens exhibited an amorphous, irregular surface smear layer. Ultrasonic irrigation, citric acid, and tetracycline hydrochloride were effective in removing the smear layer. Use of ultrasonic irrigation before and after acid application improved the exposure of dentinal fibrils.

Source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=10332361&dopt=Abstract antibiotics, tetracycline

osu.edu

BACKGROUND: Periodontal regeneration has been a relentless goal of the periodontist. Perhaps the oldest and most frequently attempted type of regeneration has involved chemical modification of the root surface. Varying results from histological and clinical studies have created controversy about the clinical effectiveness of root surface decalcification. RATIONALE: This systematic review assesses the efficacy of root surface biomodification through the use of citric acid, tetracycline, or ethylenediaminetetraacetic acid (EDTA) in patients with chronic periodontitis. FOCUSED QUESTION: Does the use of chemical root declacification result in effective periodontal regeneration and improved clinical outcomes in patients with chronic periodontitis? SEARCH PROTOCOL: The Cochrane Database of Systematic Reviews; Database of Abstracts of Reviews of Effectiveness; Cochrane Central Register of Controlled Trials; American College of Physicians Journal Club, evidence-based MEDLINE journals; and National Center for Biotechnology Information PubMed Journals, as well as Dogpile, Google, and Copernic search engines were screened. Hand searches were performed on the Journal of Clinical Periodontology, Journal of Periodontology, Journal of Periodontal Research, and Periodontology 2000. Searches were performed for relevant clinical trials published through September 25, 2002. SELECTION CRITERIA: INCLUSION CRITERIA: Histological and clinical studies evaluating the effects of citric acid, tetracycline, or EDTA on root surfaces of patients with chronic periodontitis were considered for inclusion. EXCLUSION CRITERIA: Studies evaluating extracellular matrix proteins (e.g., fibronectin), enamel matrix proteins (e.g., amelogenins), or other proteins or growth factors applied to the root surface were not included. DATA COLLECTION AND ANALYSIS: Primary outcome measures included changes in connective tissue attachment, cementogenesis, clinical attachment levels, probing depths, and gingival recession. Secondary outcome measures included changes in bone level, gingival inflammation, and plaque levels. Results for continuous outcome measures for primary variables (clinical attachment levels, probing depths, and recession) were expressed as mean differences or standardized mean differences. Clinical attachment levels and reduction in probing depth were evaluated using meta-analysis. All papers were rated according to methodological strength of evidence. MAIN RESULTS: 1. Thirty-four studies incorporating a total patient population of 575 were analyzed: 26 for citric acid, 5 for tetracycline, and 3 for EDTA treatment. 2. Four of 8 human histological studies reported regeneration with the use of citric acid. Only 1 of 18 clinical studies reported attachment gain. 3. Of the 5 studies examined using tetracycline, 1 histological study and 1 clinical study reported attachment gain. 4. No regeneration was reported in the 3 studies evaluating the use of EDTA. 5. Meta-analysis performed on 28 clinical trials did not show any significant effects of acid root treatment on attachment level gains or probing depth. REVIEWER'S CONCLUSIONS: 1. Evidence to date suggests that the use of citric acid, tetracycline, or EDTA to modify the root surface provides no benefit of clinical significance to regeneration in patients with chronic periodontitis. 2. The best method for ascertaining the clinical efficacy of acid-treated root regeneration would be to conduct a randomized clinical trial with sufficient statistical power that is supported by quantitative histological evaluation. 3. The majority of the studies that evaluated the regenerative potential of root surface modifiers were observational in nature; therefore, the value of conclusions reached in this manuscript must be carefully considered.

Source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=14971255&dopt=Abstract [PubMed - in process]