BACKGROUNDVancomycin-resistant Enterococci (VRE) cause serious infections that are difficult to treat. We carried out this study to determine the mutant prevention concentration (MPC) of linezolid when combined with minocycline against VRE strains, to determine the mechanism of drug resistance in vitro, and to provide a theoretical basis for the rational use of drugs against VRE.

METHODSThe minimum inhibitory concentrations (MICs) of linezolid and minocycline against 30 Enterococci (E.) isolates (including 20 VRE strains) were determined by the broth microdilution method. Drug interactions were assessed by the checkerboard microdilution tests and confirmed by time-kill studies. Two vancomycin-susceptible strains N27 and N40 (linezolid MIC, 2 g/ml; minocycline MIC, 4 µg/ml) and control strains E. faecalis ATCC 29212 and ATCC 51299 were also tested. The MPCs of linezolid and minocycline (alone and combined) were determined using the agar dilution method. Strains showing stable resistance were analyzed by polymerase chain reaction (PCR) amplification of domain V of the 23S rRNA gene.

RESULTSCheckerboard titration studies revealed synergistic effects of combination therapy in 26.7% of 30 E. isolates. Antagonism was not observed. The G2576U mutation was detected in stable linezolid-resistant strains of ATCC 29212, N40, and N27 before and after resistance screening, and MIC values increased with the number of G2576U mutations. The MPC of linezolid against E. decreased dramatically when combined with minocycline, and vice versa.

CONCLUSIONLinezolid or minocycline alone produce resistant strains; however, their joint use may reduce the MPC of each agent against VRE, thereby decreasing resistant mutants and bacterial infections.

Acetamides ; pharmacology ; Anti-Bacterial Agents ; pharmacology ; Anti-Infective Agents ; pharmacology ; Drug Therapy, Combination ; Enterococcus ; drug effects ; genetics ; Linezolid ; Microbial Sensitivity Tests ; Minocycline ; pharmacology ; Mutation ; Oxazolidinones ; pharmacology ; Vancomycin Resistance

OBJECTIVETo observe the effect of different doses of acetamide on the histopathology in the cerebral cortex of rats with tetramine (TET) poisoning and to provide a basis for the treatment of fluoroacetamide poisoning with acetamide.

METHODSEighty clean Sprague-Dawley rats were randomly divided into five groups: saline control group,dimethylsulfoxide water solution control group,TET poisoning group, acetamide (2.88 g/kg/d) treatment group, and acetamide (5.68 g/kg/d) treatment group, with 16 rats in each group. Rats in the poisoning group and treatment groups were poisoned with TET by intragastric administration after fasting; then, saline was injected intramuscularly into rats of the poisoning group, and different doses of acetamide were injected intramuscularly into rats of treatment groups; the course of treatment was 5 d. At 3 h, 12 h, 48 h, and 7 d after treatment, the cerebral cortex was harvested from rats in each group, and the histopathological changes in the cerebral cortex were evaluated under light and electron microscopes.

RESULTSThe light microscopy showed that the TET poisoning group had hypoxia changes in the cerebral cortex, which worsened over time; the treatment groups had reduced hypoxia changes, and the acetamide (2.88 g/kg/d) treatment group had more reduction than the acetamide (5.68 g/kg/d) treatment group. The electron microscopy showed that the apoptosis of neuronal cells were the main pathological changes in the TET poisoning group; the treatment groups had reduced apoptotic changes, and the acetamide (2.88 g/kg/d) treatment group had more reduction than the acetamide (5.68 g/kg/d) treatment group.

CONCLUSIONNo pathological changes associated with the synergistic toxic effect of acetamide and TET are found in the cerebral cortex. Acetamide (2.88 g/kg/d) could reduce central nervous lesions, but the efficacy is not improved after increasing the dose. For patients who cannot be identified with TET or fluoroacetamide poisoning, acetamide could be considered for treatment.

Acetamides ; pharmacology ; Animals ; Bridged-Ring Compounds ; toxicity ; Cerebral Cortex ; drug effects ; pathology ; Disease Models, Animal ; Male ; Rats ; Rats, Sprague-Dawley

Acetamides ; pharmacology ; Animals ; Bridged-Ring Compounds ; poisoning ; Disease Models, Animal ; Female ; Male ; Rats ; Rats, Sprague-Dawley ; Troponin I ; blood

AIMTo synthesize oxazolindinone derivatives and test their antibacterial activities.

METHODS3-Halo-4-methylaniline was acylated with benzyl chloroformate, followed by cyclization with (R)-glycidyl butyrate, acylation with methanesulfonyl chloride, substitution with NaN3, reduction with H2 + Pd/C or P(OMe)3 + HCl, acylation with Ac2O, and bromination with NBS to form bromides VIIIa and VIIIb, Substitution of the bromides with various amines including aliphatic amine and aromatic amine provided the target compounds IXa and IXb. The in vitro antibacterial activity of the target compounds was tested.

RESULTSFifty one new compounds were designed and synthesized. And their structures were confirmed by 1H NMR and elemental analyses or MS. Some physical constants such as [alpha]D25 were reported also. Compounds VIIb, IXa1, IXa2, IXa7, IXb1, IXb3, IXb10, IXb16 and IXb23 had moderate in vitro antibacterial activity against G+ bacteria but they were less active than linezolid or norfloxacin.

CONCLUSIONInsertion of methylene group between 4-position of phenyl and morpholinyl group in linezolid derivatives can not increase the antibacterial activity.

Acetamides ; pharmacology ; Anti-Bacterial Agents ; chemical synthesis ; chemistry ; pharmacology ; Linezolid ; Microbial Sensitivity Tests ; Molecular Structure ; Oxazolidinones ; chemical synthesis ; chemistry ; pharmacology ; Staphylococcus ; drug effects ; Streptococcus ; drug effects

OBJECTIVETo observe the effect of fluoroacetamide on cardiomyocytes of rat and the antidotal effect of acetamide.

METHODS4 groups of SD rats were treated with various dosages of fluoroacetamid(p.o.) and 2 groups of them were treated with acetamide(i.p.). The changes of cardiomyocytes and serum AST, LDH, CK, CK-MB and HBDH were measured at different intervals after poisoning.

RESULTSIn the group treated with fluoroacetamid 8 mg/kg. bw, serum AST[(589.58 +/- 821.72) U/L], CK[(916.78 +/- 343.55) U/L], HBDH[(504.47 +/- 148.88) U/L] raised obviously compared with control[(187.70 +/- 46.87), (755.65 +/- 498.90), (347.25 +/- 228.40) U/L respectively] (P < 0.01), and the pathological findings such as degeneration, liquefactive necrosis and filtration of inflammatory cells in cardiac muscles were observed 24 hours later, while all the male dead within 3 days. In the group treated with fluoroacetamid 4 mg/kg. bw, serum LDH and HBDH rose significantly compared with control(P < 0.01) 5 day later. On the day of 10, myocardial enzymes restored in all experiment groups with some interstitial fibroblastic proliferation. The pathological changes were reduced in the group treated with acetamide synchronously (100 mg/kg. bw).

CONCLUSIONAcute intoxication of fluoroacetamide could damage cardiomyocytes while acetamide could reduce the injury of them, but the injury was reversible. The levels of serum myocardial enzymes could be a usable index for early diagnosis.

Acetamides ; pharmacology ; Alanine Transaminase ; blood ; Animals ; Antidotes ; pharmacology ; Creatine Kinase, MB Form ; blood ; Fluoroacetates ; toxicity ; L-Lactate Dehydrogenase ; blood ; Myocytes, Cardiac ; drug effects ; pathology ; Rats ; Rats, Sprague-Dawley

The objective of this study was to investigate the effect of hexamethylene bisacetamide (HMBA) on differentiation of HL-60 cells and its possible molecular mechanism. HL-60 cells were co-cultured with different concentrations of HMBA (0.5, 1, 2 mmol/L) for 4 days, then the proliferation was assayed by MTT at different time points. Wright-Giemsa staining was used to observe the change in morphology. Cell differentiation antigen CD11b expression and the altered distribution of cell cycle in HL-60 induced by HMBA were analyzed by flow cytometry. The expressions of c-myc, mad1, p21, p27, hTERT and HDAC1 mRNA were detected by RT-PCR. The results indicated that the proliferation of HL-60 cells was inhibited by HMBA in a time-and-dose-dependent manner. Upon 2 mmol/L HMBA treatment, the HL-60 cells arrested at G(0)/G(1) phase and differentiated into granular line in morphology, with the up-regulation of CD11b expression. The expression of c-myc and hTERT mRNA obviously down-regulated, the expression of p21, p27 and mad1 mRNA up-regulated, while there was no change of the expression of hTERT mRNA. It is concluded that effect of HMBA on the differentiation of HL-60 cells may partly contribute to switch from c-myc to mad1 expression, to up-regulate expressions of p21 and p27 mRNA, and down-regulate hTERT mRNA expression, while there is no relation with the expression of HDAC1 mRNA.
Acetamides ; pharmacology ; Antineoplastic Agents ; pharmacology ; Cell Cycle ; drug effects ; Cell Differentiation ; drug effects ; genetics ; Cell Proliferation ; drug effects ; HL-60 Cells ; Humans

In order to develop potent antidiabetic agents that have inhibitory effect to a-glucosidase, twelve β-acetamido ketone derivatives such as N-{[(substituted-4-oxo-thiochroman-3-yl)phenyl]-methyl}acetamide are designed and synthesized through one-pot Dakin-West reaction. Their chemical structures are confirmed by 1H NMR, 13C NMR, IR and HR-MS. In vitro α-glucosidase inhibition assays of compounds 4a-41 were carried out using glucose oxidase method. The result indicated that most of them possess inhibitory activity in vitro. Compound 4k showed the most potent inhibitory activity with 87.3% inhibition of α-glucosidase at the concentration of 5.39 mmol x L(-1). The structure-activity relationship of these β-acetamido ketone derivatives was discussed preliminarily. Moreover, the molecular docking method was used to study the interaction mode of compound 4k and α-glucosidase. Our results will be helpful for designing of α-glucosidase inhibitors in the future.
Acetamides ; Glycoside Hydrolase Inhibitors ; chemical synthesis ; pharmacology ; Hypoglycemic Agents ; chemical synthesis ; pharmacology ; Molecular Docking Simulation ; Structure-Activity Relationship ; alpha-Glucosidases ; metabolism

OBJECTIVETo investigate the effects of acetamide at different doses on the expression of inhibitory amino acids (gamma-aminobutyric acid, GABA) and excitatory amino acid (glutamate, Glu) in the cerebral cortex of rats with acute tetramine (TET) poisoning.

METHODSEighty Sprague-Dawley rats (SPF) were randomly divided into five groups, with 16 rats in each group: saline control group, dimethyl sulfoxide (DMSO) control group, TET exposure group, high-dose (2.8 g/kg/d) acetamide treatment group, and super-high-dose (5.6 g/kg/d) acetamide treatment group. Rats in the exposure group and treatment groups were exposed to TET by intragastric administration after fasting, and were then intramuscularly injected with saline or different doses of acetamide in the following 5 days. The cortex of the temporal lobe was collected at 3 h, 12 h, 48 h, or 7 d after treatment. The expression levels of GABA and Glu in the cortex of the temporal lobe were determined by average optical density (OD) values in immunohistochemistry.

RESULTS1) Expression of GABA: The OD value of GABA in TET exposure group started to increase at 12 h after treatment, reached the peak at 48 h, and decreased to the normal level at 7 d. In the high-dose acetamide treatment group, the increase in OD at 12 h was not so significant as that in the TET exposure group, OD value decreased to the normal level at 48 h and was lower than that in the exposure group, and the changes were more like those in the control groups. In the super-high-dose acetamide treatment group, OD value began to increase significantly at 3 h and was significantly higher than that in the TET exposure group (P < 0.01), it reached the peak at 12 h, and was restored to the normal value at 48 h. 2) Expression of Glu: The OD value of Glu in TET exposure group at 3 h after treatment was significantly lower than those in the two control groups, it increased gradually from 12 h to 48 h, and recovered to the normal level at the 7th d. The changes in the high-dose acetamide treatment group were similar to those in the TET exposure group, but became more like those in the control groups after 48 h; the OD value in super-high-dose acetamide treatment group was significantly higher than that in the TET exposure group at 3 h after treatment (P < 0.01), while no significant difference was found at 12 h; it was significantly lower than those of all other groups at 48 h and 7 d (P < 0.01).

CONCLUSIONSTreatment with high dose of acetamide has some curative effect on TET poisoning-induced central nervous lesion, while the effect of super-high-dose acetamide on expression of neurotransmitters is too complex to evaluate.

Acetamides ; pharmacology ; Animals ; Bridged-Ring Compounds ; poisoning ; Cerebral Cortex ; drug effects ; metabolism ; Female ; Glutamic Acid ; metabolism ; Male ; Rats ; Rats, Sprague-Dawley ; gamma-Aminobutyric Acid ; metabolism

In an attempt to clarify the protective action of an antioxidant agent against acute toxicity of thioacetamide (TAA) and in order to throw some light on an satisfying concept of the mechanism of its action, a single dose of alphatocopherol (200 mg per kg) was given orally by stomch tube to male mice prior to the administration of thioacetamide in a dose of 200 mg per kg of body weight. Sections of liver samples, obtained from the mice which were sacrificed at intervals of 3, 6, 9, or 12 hours after TAA administration, were stained using the methyl green-pyronin technique. At 3 hours following TAA administration, the pretreatment with alpha-tocopherol inhibited almost completely such alterations of the hepatocytes in the animals given TAA alone, as revealed by loss and clumping of cytoplasmic pyroninophilic granules in the periportal zone of the lobule. At 6, 9, and l2 hours, the prevention of alpha-tocopherol was incomplete in degree and extent. The changes of the hepatocytes were more intense and extensive in the TAA-treated 6 to 12 hour-groups than in the 3 hour-group of TAA-treated ones. Some discussion is given of the mechanism of TAA toxicity, with respect to the microsoma1 lipid peroxidation.
Acetamides/poisoning* ; Animal ; Hepatitis, Toxic/pathology* ; Hepatitis, Toxic/prevention & control ; Liver/pathology* ; Male ; Mice ; Vitamin E/pharmacology* ; Vitamin E/therapeutic use

OBJECTIVESearching for more potent and less toxic HMBA-related agents.

METHODSHuman erythroleukemia cell K562, murine erythroleukemia cell (MEL) and its sub-line MEL DS19 were used as target cells to select a cell line which is the most sensitive to HMBA, then analyzed the activity of inducing differentiation of two new designed HMBA derivatives: HMBPA [hexamethylenebi (3-pyridin) amide] and Co-HDTA (ethylenediaminetetra acetic acid cobalt) using cell biology, cytochemical and molecular biology techniques.

RESULTSWe found that the MEL DS19 cells were most sensitive to HMBA (benzidine positive, B+ approximately 76%). Co-HDTA can inhibit the growth of MEL DS19, but induces differentiation just in a small population (B+ 2% approximately 4.5%). Between 0.02 approximately 5 micromol/L, HMBPA induces 3% approximately 8% cells committed to differentiation with little inhibition of cell proliferation. 1 micromol/L HMBPA and 2 mmol/L HMBA together, can obviously increase the percentage of differentiated cell (B+ approximately 72%), inhibit DNA synthesis and accelerate beta-globin transcription.

CONCLUSIONThe new HMBA derivatives may provide potential cancer differentiation inducers.

Acetamides ; chemistry ; pharmacology ; Animals ; Antineoplastic Agents ; pharmacology ; Cell Differentiation ; drug effects ; Cell Division ; drug effects ; Globins ; biosynthesis ; genetics ; Humans ; K562 Cells ; Leukemia, Erythroblastic, Acute ; metabolism ; pathology ; Mice ; Pyridines ; chemistry ; pharmacology ; RNA, Messenger ; genetics ; Tumor Cells, Cultured