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PubMed1977

Effects of oral neomycin and kanamycin in chronic uremic patients: I. Urea metabolism.

The fate of portal ammonia derived from intestinal urea degradation was examined in 15 experiments in patients with chronic renal failure. The kinetics of labelled urea metabolism were studied before and again during the administration of oral neomycin or kanamycin. Detectable absorption of both drugs generally occurred, but urea clearance and estimated glomerular filtration rate did not significantly change during antibiotic administration. In seven experiments a significant fall in urea degradation (65% to 95%) occurred during antibiotic administration. Analysis of the effect of antibiotics was confined to these seven experiments. In the control periods, there were no differences in urea metabolism or renal function between these patients and those in whom urea degradation was not suppressed. If ammonia derived from urea degradation is converted back to urea in the liver, then suppression of degradation would lead to an equal decrease in urea production, and the difference between production and degradation ("appearance") would remain constant. However, if urea-derived ammonia is used for protein synthesis, suppression of degradation would permit the formerly degraded urea to appear in urine and body fluids and thus to increase urea appearance. In these seven experiments, we found no change in urea appearance during antibiotic administration. We conclude that portal ammonia is reincorporated into urea in chronic renal failure and is not utilized significantly for protein synthesis.

Administration, Oral↗
PubMed2006

Neomycin-capped aromatic platforms: quadruplex DNA recognition and telomerase inhibition.

A series of aminoglycoside-capped macrocyclic structures has been prepared using intramolecular bis-tethering of neomycin on three aromatic platforms (phenanthroline, acridine, quinacridine). Based on NMR and calculations studies, it was found that the cyclic compounds adopt a highly flexible structure without conformational restriction of the aminoglycoside moiety. FRET-melting stabilization measurements showed that the series displays moderate to high affinity for the G4-conformation of human telomeric repeats, this effect being correlated with the size of the aromatic moiety. In addition, a FRET competition assay evidenced the poor binding ability of all macrocycles for duplex DNA and a clear binding preference for loop-containing intramolecular G4 structures compared to tetramolecular parallel G4 DNA. Finally, TRAP experiments demonstrated that the best G4-binder (quinacridine ) is also a potent and selective telomerase inhibitor with an IC(50) in the submicromolar range (200 nM).

Acridines↗
PubMed1988

Effect of pertussis toxin and neomycin on G-protein-regulated polyphosphoinositide phosphodiesterase. A comparison between HL60 membranes and permeabilized HL60 cells.

The promyelocytic HL60 cell can be differentiated with dimethyl sulphoxide or dibutyryl cyclic AMP leading to the appearance of fMetLeuPhe receptors on the cell surface. G-protein-stimulated polyphosphoinositide phosphodiesterase (PPI-pde) activity was assessed in membranes prepared from both differentiated and non-differentiated HL60 cells. Both the extent of the response and the rank order of potency of the GTP analogues to stimulate PPI-pde activation (guanosine 5'-[gamma-thio]triphosphate (GTP[S]) greater than guanosine 5'-[beta gamma-imido]triphosphate (p[NH]ppG) greater than guanosine 5'-[beta gamma-methylene]triphosphate (p[CH2]ppG) remains unchanged after differentiation with dimethyl sulphoxide. In comparison, differentiation by dibutyryl cyclic AMP leads to diminution of PPI-pde activity when stimulated by GTP[S] or fluoride, but not by millimolar concentrations of Ca2+. GTP[S]-stimulated PPI-pde in membranes is sensitive to the presence of Ca2+ (pCa 8-5). Pertussis-toxin pretreatment of intact HL60 cells leads to inhibition of both the secretory response and the formation of inositol phosphates when stimulated by fMetLeuPhe. In contrast, pertussis-toxin pretreatment has no effect on either GTP[S]- or fluoride-stimulated PPI-pde. Neomycin in a concentration-dependent manner inhibits both GTP[S] plus Ca2+ (pCa 5)-stimulated secretion and PPI-pde activation in streptolysin-O-permeabilized cells. The extent of PPI-pde activation in membranes compared with streptolysin-O-permeabilized cells reveals that the membrane preparation does not possess all the components that make up the inositide signalling system.

Calcium↗
PubMed2003

Efficacy of intramammary treatment with procaine penicillin G vs. procaine penicillin G plus neomycin in bovine clinical mastitis caused by penicillin-susceptible, gram-positive bacteria--a double blind field study.

The efficacy of intramammary treatments containing procaine penicillin G alone (treatment A) or a combination of procaine penicillin G and neomycin (treatment B) was compared in treating clinical bovine mastitis caused by gram-positive bacteria susceptible in vitro to penicillin G. Both treatments were supplemented with a single intramuscular injection of procaine penicillin G on the first day of treatment. The study was carried out using a double blind design on commercial dairy farms in Southern Finland. A total of 56 quarters were treated with treatment A and 61 with treatment B. The cure rates for both treatments were equal, which suggests that the use of the penicillin G-aminoglycoside combination does not increase the efficacy of the treatment over that achieved by using penicillin G alone in bovine clinical mastitis caused by penicillin-susceptible, gram-positive bacteria.

Animals↗
PubMed2000

Controlled multicenter study on chronic suppurative otitis media treated with topical applications of ciprofloxacin 0.2% solution in single-dose containers or combination of polymyxin B, neomycin, and hydrocortisone suspension.

Otic drops of either ciprofloxacin 0.2% solution (CIP) or a combination of polymyxin B, neomycin, and hydrocortisone suspension (PNH) were administered for 6 to 12 days to patients (14-71 years old) with chronic suppurative otitis media in a randomized, nonblinded, multicenter clinical trial. Two hundred thirty-two enrolled patients were analyzed for efficacy on a "per protocol" basis. The most frequently identified causal agents were Staphylococcus aureus (28% of the patients), Pseudomonas aeruginosa (19%), and Staphylococcus sp (9%). Clinical success was observed in 91% and 87% of the CIP-and PNH-treated patients, respectively. At 1-month follow-up, 4% of CIP and 6% of PNH patients showed a relapse of otorrhea. Bacteriologic eradication was seen in 89% and 85% of patients in the CIP and PNH groups, respectively. At 1-month follow-up, reinfection or recurrence of infection appeared in 3 patients in the PNH group and in 1 patient in the CIP group. Both treatments were well tolerated. The most frequently reported adverse events were pruritus, stinging, and earache. Audiometric tests did not show changes attributable to study drugs in any but 1 patient in the PNH group. This clinical trial shows that topical 0.2% ciprofloxacin solution in single-dose containers is effective and well tolerated in patients with chronic suppurative otitis media.

Administration, Topical↗
PubMed1984

Use of adeno-associated virus as a mammalian DNA cloning vector: transduction of neomycin resistance into mammalian tissue culture cells.

Adeno-associated virus (AAV) is a human DNA virus that has a broad host range and can be grown both as an integrated provirus and as a lytic genome. These properties suggested that AAV may be useful as a mammalian transduction vector. To test this possibility, we have isolated a recombinant AAV viral stock in which the neomycin resistance gene was substituted for the AAV capsid genes. Using this recombinant stock, we have demonstrated that AAV can be used to transduce foreign DNA into human and murine tissue culture cells. In addition, we have demonstrated that, if the transductants are superinfected with a helper virus (adenovirus), the recombinant AAV genome is rescued from the proviral state and amplified to high copy number. These unique features of AAV vectors suggest that they may have a broad utility in the study of biological problems. Because AAV, itself, is nonpathogenic in both humans and animals, these vectors also may be useful for the purpose of gene therapy.

Adenoviridae↗
PubMed2004

Neomycin prevents the wortmannin inhibition of insulin-stimulated Glut4 translocation and glucose transport in 3T3-L1 adipocytes.

Insulin stimulates the movement of the facilitative glucose transporter glucose transporter-4 (Glut4) from an intracellular compartment to the plasma membrane in adipocytes and muscle cells, resulting in an increased rate of glucose uptake. Insulin-stimulated Glut4 translocation and glucose transport are abolished by wortmannin, a specific inhibitor of phosphatidylinositol 3'-kinase (PI3K). Here, we demonstrate that neomycin, a drug that masks the cellular substrate of PI3K, phosphatidylinositol 4,5-bisphosphate (PIP), prevents wortmannin inhibition of insulin-stimulated (2)Glut4 translocation and glucose transport without activating protein kinase B, a downstream effector of PI3K. These results suggest that PIP(2) may have an important regulatory function in insulin-stimulated Glut4 translocation and glucose transport.

3T3 Cells↗
PubMed1992

Aztreonam versus colistin-neomycin for selective decontamination of the digestive tract in patients undergoing bone marrow transplantation: a randomized study.

Aztreonam (Az), a minimally absorbable monobactam antibiotic, was compared to colistin plus neomycin (CN), for intestinal decontamination during Bone Marrow Transplantation (BMT) in a controlled study. Thirty-four consecutive patients were randomized in two groups and evaluated for number of febrile episodes, days of fever, fecal cultures and clinical symptoms related to infections or colonizations. No significant differences were observed suggesting that Az is at least as effective as the CN regimen and may be considered as an alternative approach for intestinal decontamination in BMT patients.

Aztreonam↗
PubMed1969

Effects of neomycin and penicillin administration on mucosal proliferation of the mouse small intestine. With morphological and functional correlations.

The effects of an oral neomycin and penicillin regimen on intestinal bacteriology and on morphology and function of the small intestine of mice were investigated. Quantitative and qualitative stool cultures on selective media of the treated animals revealed only growth of yeast organisms. The treated animals developed enlargement of the ceca with fluid contents and watery stools, resembling characteristics of germfree animals. Radioautography with tritiated thymidine revealed an increased epithelial cell migration rate in the mice treated with the antibiotics for 3 to 5 wk. A slight increase in villus height was also noted. The treated male mice showed greater variance than the treated females in epithelial cell migration rates. Histochemical staining reactions showed a decrease in nonspecific esterase and in NADH dehydrogenase activity in the proximal gut of the antibiotic animals. Stains of distal gut and those for acid and alkaline phosphatase, NADPH dehydrogenase, lactic dehydrogenase, and succinic dehydrogenase were similar to the controls. A slight increase in sucrase activity and a slight decrease in lactase activity in the antibiotic animals was observed in contrast to control animals. Germfree mice, however, had greater sucrase and lactase activity. Transport of L-methionine was slightly reduced in the distal segment of the treated animals. Since the direction of these changes is away from the intestinal state observed in germfree animals, they are probably the result of the direct action of the antibiotics on the gut.

Animals↗
PubMed2000

Development of a competitive PCR method for in vitro and in vivo quantification of herpes simplex virus thymidine kinase and neomycin resistance-expressing cells used in a clinical trial.

The aim of this study was to set up a sensitive and specific method to quantify the number of gene-modified cells in a gene therapy clinical trial currently underway at our institution. This trial involves the use of retrovirally transduced allogeneic T cells expressing the herpes simplex-1 thymidine kinase (HSV-TK) and neomycin-phosphotransferase (NeoR) resistance gene. Quantification by competitive PCR was performed, with two homologous internal standards (deltaTK, deltaNeoR), 30 bp shorter than the target sequences (TK, NeoR), coupled to fluorescent laser-based detection. Assessment of the amplification systems procedures was carried out for each sequence. The 30-bp deletion did not affect the amplification efficiency significantly. Determination of the plateau phase of both amplified sequences demonstrated that each sample must be quantified during the predetermined exponential phase. Finally, a blinded study of a transduced cell dilutions panel validated the overall methodology. The competitive PCR was applied to quantification of the retroviral transduction process by quantifying the NeoR gene in transduced PBMC samples (prior to G418 selection) from 18 donors in our clinical trial. A mean transduction efficiency of 9.78% +/- 1.37% was observed. We also quantified TK-expressing donor transgenic T cells in a murine GvHD model. Results demonstrated on initial expansion of donor HSV-TK- expression T cells as well as a significant ganciclovir (GCV)-induced decrease correlated with the number of circulating gene-modified T cells. Therefore, we have developed an efficient gene quantification tool that should be useful for in vivo monitoring of gene-modified cells.

Animals↗
PubMed1998

Murine bone marrow expressing the neomycin resistance gene has no competitive disadvantage assessed in vivo.

The neomycin phosphotransferase (neo) gene is one of the most common marker genes used in gene transfer experimentation, but potential effects of neo gene expression in vivo have not been systematically investigated. Several early clinical retroviral gene transfer studies have suggested that neo gene expression could have deleterious effects on hematopoiesis, owing to a discrepancy between the level of neo-marked transduced marrow progenitor cells compared with mature circulating progeny cells posttransplantation (Brenner et al., 1993; Kohn et al., 1995; Brenner, 1996b). We examined the long-term in vivo repopulating ability of bone marrow from transgenic mice expressing neo from a strong constitutive promoter using a competitive repopulation assay. Different ratios of neo transgenic and wild-type congenic marrow cells were cotransplanted into W/Wv recipient mice. The percentages of blood cells containing the neo transgene in each group of recipient mice monitored for 4 months posttransplantation closely matched the input ratios of neo transgenic to congenic control marrow cells. Similar concordances of engraftment with input ratios of neo transgenic cells were also found in spleen, thymus, and whole marrow of recipient mice at 4 months posttransplantation. Analysis of the beta-hemoglobin phenotype (beta(single) for the neo transgenic and C57 control cells and beta(diffuse) for the congenic competitor HW80 cells) in recipients confirmed erythroid repopulation from neo transgenic marrow cells at levels matching the input ratios. We conclude that hematopoietic cells expressing neo had no engraftment or maturation defects detectable in vivo. These results suggest that the low-level contribution of vector-marked cells to circulating populations in clinical trials is not due to direct deleterious effects of neo gene expression on hematopoiesis.

Animals↗
PubMed1984

Gentamicin- and neomycin-resistant mutants of Escherichia coli K-12 cross-resistant to nitrofurans.

Gentamicin and neomycin-resistant mutants of Escherichia coli K-12 were isolated some of which were resistant to nitrofurans, chlorate, P1 and lambda bacteriophages as well as to all aminoglycoside antibiotics tested. Previously isolated nitrofuran-resistant mutants were not cross-resistant to the tested aminoglycosides, chlorate and bacteriophages. The aminoglycoside-resistant mutants exhibiting cross-resistance had enhanced membrane Mg2+-ATPase and decreased periplasmic alkaline phosphatase activity compared to their parent sensitive strains. The mutants were also defective in the fermentation of sugars, reduction of nitrate and nitrite, and in formate dehydrogenase activity. Preliminary genetic studies indicated that the pleiotropic mutation might be located in the upper left quadrant of the E. coli K-12 chromosome linkage map. It is postulated that such mutants with gross membrane alterations have impaired accumulation of aminoglycoside and nitrofuran antibiotics.

Adenosine Triphosphatases↗
PubMed2025

The aphA1 kanamycin and neomycin resistance gene originated in Klebsiella michiganensis.

BACKGROUND: The origins of several antibiotic resistance genes have been traced to intrinsic genes present in bacterial chromosomes. The aphA1 gene, which confers resistance to the aminoglycosides kanamycin and neomycin, is commonly found in diverse Gram-negative bacterial pathogens, and is associated with several different mobile genetic elements. However, its origin had not been identified. OBJECTIVES: To determine whether the aphA1-containing segments in novel compound and pseudo-compound transposons found in three historic plasmids, pIE545, R478 and Rts1, are found in the chromosome of a specific bacterial species. METHODS: Passenger segments of transposons containing the aphA1 gene were compared to one another and to chromosomal sequences in GenBank using BLAST. RESULTS: In pIE545, aphA1 is in a 5424 bp compound transposon, TnaphA1-pIE545, that is bounded by directly oriented copies of IS102. The 3.3 kb aphA1-containing passenger segment is >99% identical to a contiguous part of several Klebsiella michiganensis chromosomes. The 4.3 kb aphA1-containing segment of the IS26-bounded pseudo-compound transposon PTnaphA1-R478 in R478 is also >99% identical to a contiguous part of several K. michiganensis chromosomes that differ in the gene content surrounding aphA1. The 2.2 kb passenger segment of the IS26-bounded PTn2680 from Rts1 arose via a third independent acquisition from a K. michiganensis chromosome. CONCLUSIONS: The aphA1 gene has been captured and mobilized on at least three occasions from K. michiganensis chromosomes with related but distinct surrounding configurations.

DNA Transposable Elements↗
PubMed1992

Targeted integration of neomycin into yeast artificial chromosomes (YACs) for transfection into mammalian cells.

Vectors have been constructed for the introduction of the neomycin resistance gene (neo) into the left arm, right arm or human insert DNA of yeast artificial chromosomes (YACs) by homologous recombination. These vectors contain a yeast selectable marker Lys-2, i.e. the alpha-aminoadipidate reductase gene, and a mammalian selection marker, neo, which confers G418 resistance. The vectors can be used to modify YACs in the most commonly used yeast strain for YAC library construction, AB1380. Specific targeting can be carried out by transfection of restriction endonuclease treated linear plasmids, with highly specific recombinogenic ends, into the YAC containing yeast cells. Analysis of targeted YACs confirmed that all three vectors can target correctly in yeast. Introduction of one of the targeted YACs into V79 (Chinese hamster fibroblast) cells showed complete and intact transfer of the YAC.

Animals↗
PubMed1996

Neomycin, spermine and hexaamminecobalt (III) share common structural motifs in converting B- to A-DNA.

The (dG)n.(dC)n-containing 34mer DNA duplex [d(A2G15C15T2)]2 can be effectively converted from the B-DNA to the A-DNA conformation by neomycin, spermine and Co(NH3)6(3+). Conversion is demonstrated by a characteristic red shift in the circular dichroism spectra and dramatic NMR spectral changes in chemical shifts. Additional support comes from the substantially stronger CH6/GH8-H3'NOE intensities of the ligand-DNA complexes than those from the native DNA duplex. Such changes are consistent with a deoxyribose pucker transition from the predominate C2'-endo (S-type) to the C3'-endo (N-type). The changes for all three ligand-DNA complexes are identical, suggesting that those three complex cations share common structural motifs for the B- to A-DNA conversion. The A-DNA structure of the 4:1 complex of Co(NH3)6(3+)/d(ACCCGCGGGT) has been analyzed by NOE-restrained refinement. The structural basis of the transition may be related to the closeness of the two negatively charged sugar-phosphate backbones along the major groove in A-DNA, which can be effectively neutralized by the multivalent positively charged amine functions of these ligands. In addition, ligands like spermine or Co(NH3)6(3+) can adhere to guanine bases in the deep major groove of the double helix, as is evident from the significant direct NOE cross-peaks from the protons of Co(NH3)6(3+) to GH8, GH1 (imino) and CH4 (amino) protons. Our results point to future directions in preparing more potent derivatives of Co(NH3)6(3+) for RNA binding or the induction of A-DNA.

Base Sequence↗
PubMed1998

Lactulose and neomycin attenuate leukocyte-endothelial cell adhesion in an animal model of inflammatory bowel disease.

OBJECTIVE: The role of intestinal flora in the pathogenesis of inflammatory bowel disease is under discussion. The objective of this study was to assess the effect of lactulose (Lac) and neomycin (Neo), both of which are used clinically for changing or reducing intestinal flora, on leukocyte-endothelial cell interaction in an indomethacin (Indo)-induced long-lasting ileitis in Sprague-Dawley rats. METHODS: Two doses of Indo (7.5 mg/kg, s.c.) were given 24 h apart. Animals were fed with standard rat chow for 10 days until 12 h prior to the experiment. Solutions of Lac (1.0 mg/kg b.w.) or Neo (0.1 g/kg) were gavaged daily for 10 days between Indo administration and the experiment. Ten mesenteric venules (30 microm diameter) per animal (n = 5 per group) were observed using intravital microscopy, and the following parameters were monitored: number of adherent and emigrated leukocytes, leukocyte rolling velocity, erythrocyte velocity, venular blood flow, and shear rate. Macroscopically visible injury was scored 0 to 5, and faecal pH was measured in the distal 20 cm of ileum. RESULTS: Ten days after Indo treatment leukocyte adherence and emigration were increased (2.2-fold and 3.3-fold vs. control, respectively) while leukocyte rolling velocity and venular wall shear rate were reduced (both parameters to 81% of control). Lac and Neo attenuated microcirculatory parameters to a similar extent while macroscopic damage was prevented only by Neo but not by Lac. The effects of both substances were accompanied by a normalization of faecal pH to control level which had been lowered by Indo. CONCLUSION: The Indo-induced increase in leukocyte-endothelial cell interaction is blunted by Lac and Neo. At the same time the Indo-induced lowering of faecal pH is normalized by both substances. The reduction of macroscopic injury by Neo but not by Lac in the chronic phase of Indo inflammation might be due to additional effects on other inflammatory cells such as macrophages.

Animals↗