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Results for “DEMETHYLCHLORTETRACYCLINE”

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At least 19 recordsLinked to original sources
PubMed1983

Role of complement and polymorphonuclear cells in demethylchlortetracycline-induced phototoxicity in guinea pigs. Inhibition by decomplementation in vivo.

In this study, demethylchlortetracycline was used as a prototype of exogenous phototoxic substances. In vitro, exposure of serum containing demethylchlortetracycline to ultraviolet-A irradiation resulted in the diminution of total complement hemolytic activity and C4, C2, C3, and C5 activities. In addition, chemotactic activity for human polymorphonuclear cells was generated, which was thermostable and antigenically related to human C5 but not human C3. In vivo, phototoxic lesions were induced in guinea pigs upon intradermal injections of demethylchlortetracycline solution, followed by ultraviolet-A irradiation. On a scale of 0-3+, the animals developed a maximal response of 2.5 at 20 h. This clinical response was associated with cellular infiltrate in the dermis, consisting of 29 +/- 2% of neutrophils at 24 h. The participation of the polymorphonuclear cells was evaluated in guinea pigs rendered neutropenic by treatment with cyclophosphamide. In these guinea pigs, demethylchlortetracycline and ultraviolet-A induced a maximal response of 0.75 +/- 0.5, which was associated histologically with 1.2 +/- 0.5% neutrophils in the dermis. The role of complement in this process was studied in guinea pigs congenitally deficient in C4, and in guinea pigs decomplemented by treatment with cobra venom factor. In contrast to normal guinea pigs, C4-deficient animals exhibited a maximal reaction of 0.83 +/- 0.16 at 6 h, which subsided within 24 h. Cobra venom factor-treated guinea pigs developed a maximal response of 0.5 at 0.5 and at 6 h. These clinical changes were associated with the development of an increased vascular permeability, as demonstrated by studies using guinea pigs injected intravenously with Evans blue solution. In animals with a normal complement system, there was intense localized bluing at the sites of phototoxic lesion. In contrast, only minimal bluing was observed in decomplemented guinea pigs. These data indicate that a normal number of polymorphonuclear cells and an intact complement system are required for the full development of demethylchlortetracycline-induced phototoxic lesions.

Animals↗
PubMed1979

[Treatment of the syndrome of inappropriate antidiuretic hormone secretion with demethylchlortetracycline (author's transl)].

A patient with a syndrome of inappropriate antidiuretic hormone secretion secondary to an undifferentiated bronchogenic carcinoma with distant metastases was treated with demethylchlortetracycline. Up until recently, treatment of this syndrome was based on water restriction and when the plasma sodium concentration became extremely low, hypertonic saline solution administration. Recently it has been demonstrated that the antibiotic demethylchlortetracycline inhibits the action of the antidiuretic hormone on the renal tubules. The drug has been used successfully in five patients with the syndrome of inappropriate antidiuretic hormone secretion. The administration of 900 mg of demethylchlortetracycline per day for 7 days in our patient produced an increase of free water clearance, diuresis, plasma sodium concentration, and plasma osmolarity. Urinary excretion of sodium and urinary osmolarity declined. Furthermore, the neurological symptoms attributed to hyponatremia improved markedly. The patient lost 6 kg during treatment, probably because of negative water balance induced by demethylchlortetracycline. Even though the administration of demethylchlortetracycline did not produce significant decreases in the glomerular filtration rate or renal blood flow in our patient, it is advisable to control the renal function in individuals treated with this drug since it may on occasion determine renal insufficiency.

Carcinoma, Bronchogenic↗
PubMed1991

Difference in label length between demethylchlortetracycline and oxytetracycline: implications for the interpretation of bone histomorphometric data.

We measured the individual lengths of fluorescent labels on the three subdivisions of the endosteal envelope in iliac bone biopsy specimens produced by the administration of both oxytetracycline and demethylchlortetracycline. Fifty-one healthy subjects and 53 patients with postmenopausal osteoporosis were labeled in the stated order, and 8 osteopenic patients were labeled in the reverse order. Whatever the order of administration, the demethylchlortetracycline label was longer than the oxytetracycline label. We conclude: (1) the difference in label lengths reflects a difference between the two compounds in some intrinsic property, whether physical, chemical, or pharmacokinetic. (2) If the calculation of extent of mineralizing surface is based on the mean length of the two labels, a suitable correction should be applied to the shorter label; alternatively, the length of the longer label alone should be used. (3) Unlabeled osteoid not due to label escape probably results from slow terminal mineralization after cessation of matrix synthesis during which too few tetracycline molecules are incorporated to exceed the threshold for visible fluorescence, rather than from the temporary interruption of mineralization followed by its resumption.

Adult↗
PubMedDate not supplied

[Treatment of the syndrome of inappropriate secretion of antidiuretic hormone with demethylchlortetracycline. Apropos of 2 cases].

Two cases of inappropriate antidiuresis are reported, one associated with small cell anaplastic bronchial carcinoma, the other secondary to acute hydrocephalus. ttreatment with demethylchlortetracycline proved effective in both cases. Treatment of the inappropriate antidiuretic syndrome is discussed and the advantages of demethylchlortetracycline emphasised. This antibiotic seems to represent the treatment of choice of the chronic syndrome of inappropriate antidiuresis.

Aged↗
PubMedDate not supplied

Effects of repeated oral doses of demethylchlortetracycline on bones and dentin of young rhesus monkeys.

Seven oral doses of demethylchlortetracycline were administered to monkeys that received serial injections of lead acetate to intravitally stain calcification sites. Bone growth was greatly inhibited, whereas dentin apposition was spared from the cumulative toxicity of demethylchlortetracycline. Cessation of bone growth and its duration could be correlated with serum levels.

Administration, Oral↗
PubMed1984

The binding of 6-demethylchlortetracycline to 70S, 50S and 30S ribosomal particles: a quantitative study by fluorescence anisotropy.

The binding of demeclocycline (6-demethylchlortetracycline) to ribosomes and ribosomal subunits from Escherichia coli was investigated by using the fluorescence anisotropy of the antibiotic to determine the extent of binding. Binding data obtained from 70S and 30S particles differed fundamentally from those obtained from 50S subunits: the first two showed a strong, specific interaction while the third did not. In addition, all three particles possessed weak, unspecific binding sites. Computer-aided least-squares analysis of the data yielded the following numbers of sites and equilibrium constants: for 30S, n1 = 1, K1 = 2.2 X 10(6) M-1, n2 K2 = 0.029 X 10(6) M-1; for 50S, n1 = 0, n2 K2 = 0.035 X 10(6) M-1; for 70S, n1 = 1, K1 = 3.2 X 10(6) M-1, n2 K2 = 0.082 X 10(6) M-1. These data resolve current disagreement in the literature and are a prerequisite for quantitative studies of the mechanism of inhibition by tetracycline of protein biosynthesis.

Computers↗
PubMed1981

Demethylchlortetracycline and griseofulvin as examples of specific treatment for mycosis fungoides.

Long-term control of mycosis fungoides in the tumour stage was achieved in one patient by daily demethylchlortetracycline therapy. On two occasions widespread nodules and tumours completely involuted within 1 month of initiating this therapy. A second patient showed complete resolution of his plaque stage mycosis fungoides after the institution of oral griseofulvin therapy for a chronic fungus infection. The disease reappeared upon stopping the griseofulvin and involuted upon its resumption. The observations are interpreted as evidence that reduction or eradication of a persistent bacterial or fungal antigen may have a remarkable ameliorative effect in selected mycosis fungoides patients.

Demeclocycline↗
PubMed1990

Effects of demethylchlortetracycline phototoxicity on the structure and functions of rat liver mitochondria.

The phototoxic effects of demethylchlortetracycline (DMCT) with UVA radiation on isolated rat liver mitochondria were studied. DMCT at concentration of 21.5 microM with 5.53 x 10(-2) J cm-3 of UVA was found to be a potent uncoupler of oxidative phosphorylation. DMCT alone also uncoupled mitochondria but at higher concentrations (105 microM). ATPase activity was remarkably induced in mitochondria exposed to DMCT (21.5 microM) plus UVA (120% of DNP-stimulated ATPase activity). Content of ATP in such mitochondria when measured after addition of ADP was much smaller than that in control mitochondria. Ultrastructurally, mitochondria treated either with DMCT (21.5 microM) or with UVA alone stayed in the condensed configuration. On the other hand, uncoupled mitochondria treated with DMCT plus UVA became swollen and were changed into the orthodox configuration.

Animals↗
PubMed2000

Mechanism of the incidental production of a melanin-like pigment during 6-demethylchlortetracycline production in Streptomyces aureofaciens.

The secondary metabolite 6-demethylchlortetracycline (6-DCT), which is produced by Streptomyces aureofaciens, is used as a precursor of semisynthetic tetracyclines. Strains that produce 6-DCT also produce a melanin-like pigment (MP). The correlation between MP production and 6-DCT production was investigated by using S. aureofaciens NRRL 3203. Production of both MP and 6-DCT was repressed by phosphate or ammonium ions, suggesting that syntheses of these compounds are controlled by the same regulators. Ten chlortetracycline-producing recombinants were derived from 6-DCT-producing mutant NRRL 3203 by gene replacement. All of the recombinants produced chlortetracycline but not MP, indicating that MP production is the results of a defect in the 6-methylation step and suggesting that the polyketide nonaketideamide is a common intermediate leading to MP as well as 6-DCT. To further examine the possibility that MP might be synthesized via the 6-DCT-biosynthetic pathway, mutants defective in 6-DCT biosynthesis were derived from a 6-DCT producer. Some of these mutants were able to produce MP, while others, including mutants with mutations in the gene encoding anhydrotetracycline oxygenase, an enzyme catalyzing the penultimate step in the pathway, produced neither 6-DCT nor MP. Production of 6-DCT and production of MP were restored simultaneously by integrative transformation with the corresponding 6-DCT-biosynthetic genes, indicating that some of 6-DCT-biosynthetic enzymes are indispensable for MP production. These findings suggest that a defect in the 6-methylation step results in redirection of carbon flux from a certain intermediate in the 6-DCT-biosynthetic pathway to a shunt pathway and results in MP production.

Anti-Bacterial Agents↗
PubMed1969

Effects of systemic demethylchlortetracycline on human cutaneous microflora.

The aerobic flora of the axilla and forehead of 20 normal human subjects was studied through a 3-week course of 600 mg of demethylchlortetracycline daily and a 3-week follow-up. In general in the axilla, an initial fall in bacterial density was followed by recovery in numbers due to the proliferation of resistant coagulase-negative cocci and diminution of the lipophilic diphtheroid group of bacteria within 1 week of treatment. During the remainder of the treatment period, the flora was essentially stable in both density and composition. In the follow-up phase, the initial flora was slowly re-established but resistant cocci persisted for more than 3 weeks. On the forehead the fall in density was slower and recovery during treatment was incomplete. Resistant coagulase-negative cocci became dominant and persisted through the follow-up phase. In two individuals, temporary colonization of the axilla by Staphylococcus aureus was seen.

Axilla↗
PubMed1976

Demethylchlortetracycline-binding proteins in uninvolved gastric mucosa of gastric carcinoma and gastric ulcer patients. Demonstration of a difference between the uninvolved mucosa of ulcer and cancer patients.

The uninvolved gastric mucosa of gastric ulcer and gastric carcinoma patients has been compared in in vitro studies as regards their capacity to bind demethylchlortetracycline (DMCT). Dialysis experiments demonstrated excessive binding of DMCT in gastric cancer. Several electrophoretic fractions were observed that bound DMCT; it was demonstrated that these fractions differed in the uninvolved mucosa of gastric ulcer and gastric cancer patients.

Adenocarcinoma↗
PubMed1978

Nephrogenic diabetes insipidus due to demethylchlortetracycline hydrochloride in a child.

Nephrogenic diabetes insipidus occurred in a 7-year-old child who had received a high dose of demethylchlortetracycline hydrochloride (DMC). The patient had a relatively elevated urinary sodium concentration in addition to isosthenuria. The nephrogenic diabetes insipidus was completely reversible within one month after cessation of DMC administration.

Child↗