Effects Of Oxytetracycline Research Articles

The immune system of cyprinid fish. The immunosuppressive effect of the antibiotic oxytetracycline in carp ( Cyprinus carpio L.)

The effect of oxytetracycline (oxyTC) upon the immune system of carp was investigated. OxyTC was administered by feeding with oxyTC-containing pellets or by intraperitoneal injection. In order to study cellular immunity, allogeneic scale transplantation was carried out. Oral administration of oxyTC had no influence upon the median survival time (MST) of the scales. However, injections with oxyTC significantly prolonged the MST from 8.5 to 11–20 days. Thus, cellular immunity was not affected by oral administration of oxyTC, but injections did have a dramatic immunosuppressive effect. To investigate the effect of oxyTC upon humoral immunity, animals were injected with rabbit red blood cells (RaRBC). During the primary and secondary response the number of rosette forming cells (RFC) in the spleen was determined. Control animals (not treated with oxyTC) developed an anti-RaRBC response up to 25000 RFC/10 6 white spleen cells but oxyTC-treated animals always showed reduced RFC numbers. In some cases the RFC number in oxyTC-treated animals was comparable with background levels in non-immunized control animals (4000 RFC/10 6 white spleen cells). Thus, irrespective of the route of administration, the humoral immune response is depressed by oxyTC. It is concluded that both humoral and cellular immune responses of carp are suppressed during treatment with oxyTC. Preliminary observations showed an increased number of granulocytes in the spleen of oxyTC-treated animals. It is tempting to speculate that in those cases where specific lymphoid defence mechanisms are blocked, the phagocytic defence system becomes more active.

Effects of oxytetracycline on solubility and synthesis of collagen in young rats.

In a recent study we demonstrated that the antibiotic oxytetracycline reduces both growth and mechanical strength of bone and skin in young rats. The present study deals with the effects of 14 days of oxytetracycline medication on salt solubility of collagen (cross-linking) and conversion of 14C-proline to 14C-hydroxyproline in collagen (synthesis). At the end of the medication period, significantly higher solubility of collagen was found in the femurs and skin of rats receiving oxytetracycline than in controls. No effect of the antibiotic on the rate of collagen synthesis could be demonstrated. These findings may indicate that oxytetracycline in young rats causes reduced mechanical strength of bone and skin by interfering with the cross-linking of collagen.

Effects of oxytetracycline on mineralization of bone in young rats.

The metabolism of minerals and collagen in young rats receiving oxytetracycline was studied by employing double-isotope techniques. The dosage of the antibiotic was adjusted to obtain plasma concentrations comparable with human therapeutic levels. Reduced mineralization and possibly increased resorption of bone were observed after oxytetracycline administration, whereas no effect on the rate of collagen synthesis could be detected.

Effects of tetracyclines on aldosterone- and insulin-mediated Na + transport in the toad urinary bladder

The effect of oxytetracycline and demethylchlortetracycline on aldosterone- and insulin-mediated Na + transport (short-circuit current) were examined in toad urinary bladders mounted in modified Ussing chambers. Oxytetracycline had little or no effect on either basal or aldosterone-mediated Na + transport. In contrast, demethylchlortetracycline markedly inhibited both basal and aldosterone-mediated Na + transport. Furthermore, demethylchlortetracycline inhibited the aldosterone response significantly out of proportion to its effects on basal Na + transport. Neither of the drugs had an effect on insulin-mediated Na + transport. Consequently, the natriuresis observed in certain patients treated with demethylchlortetracyline may be related to drug-induced renal resistance to the effects of aldosterone.

Effects of oxytetracycline on the mechanical properties of bone and skin in young rats.

The influence of the tetracycline antibiotics on growing bones has been disputed. In the present study 58 young male rats were given intraperitoneal injections twice a day for 2 weeks; half of the rats received oxytetracycline and the other half placebo. The concentration of oxytetracycline in plasma was comparable with therapeutic levels in man. Compared with the control animals the oxytetracycline rats had, at the end of the medication period, a significantly lower weight (7 per cent), shorter bones (1--2 per cent), lower bending strength of both the tibia diaphysis (9 per cent) and the distal femur metaphysis (22 per cent) and even lower tensile strength of intact (17 per cent ) and sutured (27 per cent) skin. The effect oxytetracycline seems to be reversible as no differences between the two groups could be detected 1--3 weeks after the end of medication.

The lack of effect of oxytetracycline on responses to sympathetic nerve stimulation and catecholamines in vascular tissue.

The effects of oxytetracycline, an inhibitor of amine binding in connective tissue, on the responses of perfused rabbit ear arteries to sympathetic nerve stimulation and to intraluminally administered noradrenaline were examined. The contractions of aortic strips to catecholamines in the presence of oxytetracycline were also examined. Oxytetracycline (0.1 mM) had no discernable effect on the magnitude of constrictions, measured as reductions in flow, produced by either nerve stimulation (0.5-10 Hz) or noradrenaline (0.5-50 ng) in the ear artery. In addition, the time taken for vessels to recover towards control flow values after endogenously released or exogenously applied noradrenaline had acted was not increased by oxytetracycline. Oxytetracycline (0.1 mM) did not alter the position or shape of the concentration-response curve to noradrenaline nor did it enhance the amplitude of individual responses to catecholamines in aortic strips. It is concluded, contrary to the observations of Powis (1973), that oxytetracycline does not increase the magnitude or duration of responses to sympathetic nerve activation or to catecholamines and that binding to connective tissue is of no material consequence in terminating their action in vascular tissue.

The effect of oxytetracycline on the response to insulin of diaphragm muscle and on lipid synthesisin vivo andin vitro in the ob/ob mouse

The insulin sensitivity of the peripheral tissues in ob/ob mice treated with oxytetracycline was assessed both in vivo and in vitro by measuring the effect of insulin on the incorporation of glucose into glycogen in diaphragm muscle and on the incorporation of glucose and 3H2O into lipids in epidymal adipose tissue. The results indicated that OTC treatment improved the insulin sensitivity of muscle but not that of adipose tissue. The results presented also indicated that oxytetracycline treatment led to a decrease in the basal incorporation of lipids into the liver in vivo and the adipose tissue in vivo and in vitro. The results are discussed in view of the relative importance of liver and adipose tissue in the lipid metabolism of ob/ob and lean mice and in view of results obtained by other workers on the effects of B-cell cytotoxic agents.

The effect of oxytetracycline on insulin resistance in obese mice.

1. Chronic oxytetracycline treatment was found to improve the insulin resistance of the obese-hyperglycaemic mouse. 2. The improved response to insulin was accompanied by decreased concentrations of circulating insulin and glucose, by a decrease in the lipid content of the liver and by an increase in the insulin-receptor sites of the liver and adipose tissue. 3. The increase in insulin-receptor sites preceded the fall in blood glucose. 4. Comparable studies done on food-restricted animals indicated that although chronic food restriction corrected the hyperinsulinaemia it did not restore the insulin-receptor sites or the hyperglycaemia.

Effect of oxytetracycline and chloramphenicol on the exocrine pancreatic function in the rat.

After a 3-day administration of oxytetracycline and chloramphenicol, respectively, to rats an approximately dose-dependent decrease in the pancreatic secretion of proteins and enzyme activities was demonstrable in vivo under exogenous stimulation. The volume and electrolyte output of the pancreatic secretion were found to remain essentially unchanged. Since short-term administration of these antibiotics did not produce any alteration in exocrine pancreatic function, an impairment in enzyme synthesis is suggested as the major cause of the observed change in secretion.

The biogenesis of mitochondria during proliferation and maturation of the intestinal epithelium of the rat. Effects of oxytetracycline

Short-term (13–16 hr) in vivo treatment of rats with oxytetracycline, as inhibitor of mitochondrial proteins synthesis, results in a strong reduction of cytochrome c oxidase activity in the intestinal epithelial cells. Not only the crypt cells but also the villous cells are affected. In addition, the mitochondrial ATPase system is altered by this treatment; sensitivity to oligomycin is lost. The results clearly indicate that biogenesis of mitochondria occurs during the entire cell cycle, during proliferation, maturation and differentiation. Since there is an increase in total cytochrome c on a protein basis in the villus as compared to the crypt, the mitochondrial biosynthetic activities in the villi serve a real increase of mitochondria rather than replacement as a result of turnover. It is argued that the effects of oxytetracycline might be related to its toxic action in the intestinal tract.

Inhibition by Oxytetracycline of the Development of the Enhanced Response to Noradrenaline in Cold-Acclimated Rats: A New Approach to the Study of Nonshivering Thermogenesis

The aim of these experiments was to depress the increased metabolic activity of the brown adipose tissue in the intact rat during acclimation to cold in order to elucidate further the possible thermogenic and endocrine functions of this tissue. The antibiotic oxytetracycline was administered twice daily for 2 weeks to rats living at 4 °C in an attempt to inhibit the proliferation of mitochondria and of mitochondrial inner membrane known to occur in the brown adipose tissue in response to cold; control rats received saline during the same period. Total cytochrome oxidase activity served as an index of the amount of mitochondrial inner membrane in brown adipose tissue, liver, and skeletal muscle. The development of an enhanced calorigenic response to intravenously infused noradrenaline served as an index of the extent of acclimation to cold.Treatment with oxytetracycline inhibited both the cold-induced increase in cytochrome oxidase activity in brown adipose tissue and the cold-induced development of an enhanced calorigenic response to noradrenaline in the intact rats; a direct correlation was noted between the amount of cytochrome oxidase in brown adipose tissue and the size of the metabolic response to noradrenaline of the intact animals. However, the amount of oxygen that could be consumed by the total cytochrome oxidase in the brown adipose tissue was itself too small to account for the increase in oxygen consumption by the rat. Treatment of the rats with oxytetracycline did not alter the cold-induced growth of brown adipose tissue (as judged by the increase in wet weight and the increase in total protein); it also did not alter the cytochrome oxidase activities of liver or skeletal muscle. The effect of oxytetracycline seems, therefore, to be fairly specific for the mitochondria of the most rapidly dividing tissue, the brown adipose tissue. The conclusion is drawn that a protein synthesized in the mitochondria of the brown adipose tissue in response to cold is essential for adaptation to cold.

The resistance of Escherichia coli to oxytetracycline.

The effects of oxytetracycline on sensitive and resistant strains of Escherichia coli were studied in relation to: (1) growth of bacteria in shaken cultures, (2) incorporation of amino acids into polypeptides by cell-free extracts, (3) binding of aminoacyl-tRNA to ribosomes. Our results support the hypothesis that resistance to the antibiotic is due to impermeability of bacteria to the drug.Evidence is also presented that there is no irreversible binding of oxytetracycline at ribosomal sites involved in protein synthesis.

Effect of oxytetracycline in a periodontal pack on sensitivity and numbers of tongue flora.

Effect of oxytetracycline in a periodontal pack on sensitivity and numbers of tongue flora.

Effect of oxytetracycline and tetracycline on glucose tolerance and serum lipids.

SummaryOxytetracycline or tetracycline, 10 mg/kg, was administered for 10 consecutive days to rabbits and rhesus monkeys. Glucose tolerance test was performed and different fractions of serum lipids were estimated in these animals before and after treatment with the antibiotics to find if their prolonged use interfered with carbohydrate and lipid metabolism. Both antibiotics diminished glucose tolerance. The pattern of serum lipids was changed. There were increases in the serum triglycerides, phospho-lipids, β-lipoprotein cholesterol and free fatty acids in most of the animals after treatment with the antibiotics. Tetracyclines should be used with caution due to the metabolic disturbances they might produce.

The Effect of Oxytetracycline on the Performance of Turkey Breeder Hens

LIMITED information is available on the effects of tetracycline antibiotics on the performance of turkey breeder hens. Several reports related to the use of antibiotics in the feeds of commercial laying hens and heavy chicken breeders have been published during the past few years (Carlson, 1959; Heywang, 1959; O’Neal and Savage, 1959; Ryan et al., 1961; Eoff et al., 1962). In general, these reports have shown improvements in egg production and feed efficiency due to the feeding of antibiotics.White-Stevens et al. (1955) reported that the continuous feeding of 100 to 200 grams of chlortetracycline per ton of feed to Beltsville Small White turkey breeders significantly increased eggs per hen housed and poults hatched per hen housed. With turkey breeder hens exhibiting a fertility problem, Green et al. (1963) observed in two experiments that tetracycline antibiotics administered through the feed or by injection prevented the precipitous drop in fertility observed …

Final report on the effectiveness of oxytetracycline in the treatment of gonorrhea in females

1.1. Penicillin, although the drug of choice in the treatment of gonorrhea, has produced a reduced susceptibility, as well as an out-right bacterial resistance during the years.2.2. This study was motivated to evaluate rigidly a second antibiotic which would give therapeutic results comparable to penicillin in the treatment of gonorrhea.3.3. The minimal dosage to date has been the use of oxytetracycline, 250 ml. intramuscularly, and oxytetracycline, 1.0 Gm. orally, given simultaneously, for one dose. With the treatment schedule, a cure rate of about 95 per cent was achieved.

Effects of oxytetracycline and oleandomycin. Separately and together in pig diets

1. Normal rations containing oleandomycin (2·5 g./ton), oxytetracycline (10 g./ton) and oleandomycin (2·5 g./ton)plus oxytetracycline (10 g./ton) were given to females and castrates which had previously received creep feed with or without oxytetracycline.2. Forty-eight pigs were individually fed on the rations from 50 to 200 lb. live-weight, a restricted scale of intake based on live-weight being adopted.3. Pigs receiving the mixed supplement and those given oxytetracycline alone grew significantly faster and utilised their feed more efficiently than those given oleandomycin alone. Differences between the mixed supplement group and those receiving oxytetracycline were not significant.4. Treatment with antibiotic, either in the creep feed or after weaning, had no effect on carcass measurements. Females had less depth of fat at the shoulder, mid-back and loin compared with castrates and the carcasses were significantly longer.5. Visceral weights were not influenced by antibiotic treatment but pigs supplemented with oleandomycin had a shorter gut than those receiving a combination of antibiotics. There was a significant reduction in gut weight n i pigs which had received unsupplemented creep feed but no consistent effect on the thickness of the intestine wall or gut diameter. Females had significantly heavier kidneys and spleens than castrates.

ON THE MECHANISM OF ACTION OF TETRACYCLINE ANTIBIOTICS. V. THE EFFECT OF OXYTETRACYCLINE ON THE REDUCTION OF TRIPHENYLTETRAZOLIUM BY STAPHYLOCOCCI AND SOME OTHER MICROORGANISMS.

Oxytetracycline-sensitive and resistant strains of Staphylococci and ofListeria monocytogenes andPasteurella multocida were tested for differences in the reduction of triphenyltetrazolium (TTC) in the presence of glucose, acetate, lactate, pyruvate, glycerol, succinate, formate, malate, citrate, serine, glycine and asparagine. The sensitive staphylococci reduced TTC more actively than the resistant ones in the presence of glucose, acetate and serine. The resistant strains reduced TTC more actively in the presence of succinate, formate, glycine, pyruvate and malate. Oxytetracycline itself only inhibited the reducing activity greatly in the sensitive staphylococci. In the resistant ones, oxytetracycline only slightly decreased the TTC reduction. The insensitivity of the reducing activity of resistant staphylococci toward the effect of oxytetracycline indicates that this activity may be one of the sites of attack by this antibiotic. Ascorbic acid contained in the injection preparation of oxytetracycline interfered with the inhibitory effect of this antibiotic on the TTC reduction by staphylococci and actually increased the activity of reduction.

ACCUMULATION OF OXYTETRACYCLINE RELEVANT TO ITS BACTERICIDAL ACTION IN THE CELLS OF ESCHERICHIA COLI.

IN the course of work on the effect of oxytetracycline on the growth of E. coli B-151-1 using a nepherometer, we observed a remarkable increase in turbidity when the cells were incubated at high concentration of oxytetracycline over 100 µg/ml, in nutrient broth. Results showed that this increase in turbidity was not caused by the increase of number of cells, but was due to a remarkable accumulation of Oxytetracycline in the cells of E. coli. Cells of E. coli B-151-1 or E. coli K-12 were collected from 1516 h culture by shaking at 30° C in nutrient broth (pH 7.2), and were washed twice with distilled water. Usually Monod's test tube was used for both growth and accumulation tests unless otherwise indicated. Usually, cells of E. coli (about 1 mg dry weight) were suspended in 10 ml. of medium in 30 ml. Monod's test tube, and the tube was shaken at 30° C on a shaking machine. The resting cells were incubated with various concentrations of oxytetracycline in nutrient broth (pH 7.2) at 30° C, and the growth was measured using a Kotaki nepherometer. The amount of oxytetracycline was expressed as that of its hydrochloride.

Effect of Oxytetracycline, Stilbestrol, and Pelleted Feed on Fattening Whiteface and Blackface Crossbred Wether Lambs

An experimental design with factorially arranged treatments was used to test two levels of oxytetracycline, two levels of stilbestrol, pelleted versus chopped feed, and whiteface versus blackface crossbred lambs. One hun|dred and twenty-eight (pair fed) lambs were used to measure weight gain, feed consump|tion, carcass grade, and yield. The greatest response was due to the increased feed con|sumption and body weight gain of the pellet-fed lambs. Covariance analysis indicated that the increased gain was almost entirely due to the increased feed consumption. Heavier lambs gave the best results from pellet feeding. Oxytetracycline and stilbestrol both increased body weight gain, which was independent of feed consumption. The use of stilbestrol resulted in a higher rate gain with the blackface crossbred lambs than with the whiteface lambs. The blackface crossbred carcasses graded and yielded better than the whitefaces. Stilbestrol fed lambs had a lower dressing percent.