RIT 2214, a new biosynthetic penicillin produced by a mutant of Cephalosporium acremonium.
(1/37)
A number of lysine-requiring auxotrophs of Cephalosporium acremonium were investigated for incorporation of side-chain precursors and for accumulation of beta-lactam compounds. One of the auxotrophs, Acremonium chrysogenum ATCC 20389, producing cephalosporin C and penicillin N only if grown in media supplemented with DL-alpha-amino-adipic acid (DL-alpha-AAA), was found to use L-S-carboxymethylcysteine (L-CMC) as a side-chain precursor for the synthesis of a new penicillin (RIT 2214). No corresponding cephalosporin was detected. The penicillin present in the culture filtrate, was concentrated by adsorption on activated carbon and successive column chromatography on Amberlite IRA-68 and Amberlite XAD-4. Final purification was achieved by cellulose column chromatography. RIT 2214 was identified as 6-(D)-[(2-amino-2-carboxy)-ethylthio]-acetamido]-penicillanic acid by spectral analysis, bioactivity spectrum, elucidation of side-chain structure and finally by semisynthesis. Its biological properties were also evaluated. (+info)
Diurnal variation in the metabolism of S-carboxymethyl-L-cysteine in humans.
(2/37)
The routes of metabolism of S-carboxymethyl-L-cysteine in humans are dependent on the time of dosing. Administration of 750 mg of S-carboxymethyl-L-cysteine (Day 1) during the day at 8:00 AM followed by a 8:00 AM to 4:00 PM urine collection revealed that S-carboxymethyl-L-cysteine S-oxide was the major urinary metabolite produced. The 4:00 PM to midnight urine collection resulted in S-(carboxymethylthio)-L-cysteine being identified as the major urinary metabolite. However, the administration of 750 mg of S-carboxymethyl-L-cysteine (day 15) during the night at midnight and analysis of the midnight to 8:00 AM urine collection found that thiodiglycolic acid was the major urinary metabolite, whereas thiodiglycolic S-oxide was identified as the major urinary metabolite in the 8:00 AM to 4:00 PM urine collection. A diurnal variation in the metabolism of S-carboxymethyl-L-cysteine was seen and, in particular, the timing of S-carboxymethyl-L-cysteine administration had a profound effect on the identity of urinary S-oxide metabolites produced. After administration at 8:00 AM the urinary S-oxides produced were S-carboxymethyl-L-cysteine S-oxide and S-methyl-L-cysteine S-oxide but at midnight the major urinary S-oxide metabolite produced was thiodiglycolic acid S-oxide. (+info)
Effects of carbocysteine on antigen-induced increases in cough sensitivity and bronchial responsiveness in guinea pigs.
(3/37)
Carbocysteine is a mucoactive drug and is being used for both acute and chronic infectious airway diseases. Although carbocysteine can repair the damage of epithelial cells caused by exposure to various agents, the effects of this agent on allergic airway diseases such as asthma and eosinophilic bronchitis with an isolated chronic cough, in both of which epithelial damage may be characteristic, is not clear. We investigated the effects of carbocysteine on antigen-induced cough hypersensitivity to inhaled capsaicin at 48 h and bronchial hyperresponsiveness to inhaled methacholine at 72 h after challenge with an aerosolized antigen in actively sensitized guinea pigs. After measuring bronchial responsiveness, we examined neutral endopeptidase (NEP) activity in the tracheal tissue. Carbocysteine (10, 30, or 100 mg/kg) was given intraperitoneally every 12 h for 3 days after antigen challenge. The number of coughs elicited by an aerosol of capsaicin (10(-4) M) was significantly (p < 0.01) decreased in carbocysteine groups (6.13 +/- 0.59 at 10 mg/kg, 4.88 +/- 0.67 at 30 mg/kg, and 4.50 +/- 0.33 at 100 mg/kg during 3 min measurement) compared with the control group (9.75 +/- 0.53). Furthermore, carbocysteine dose dependently repaired the antigen-induced decrease of NEP activity in the tracheal tissue, but it did not influence the bronchial hyperresponsiveness or bronchoalveolar lavage cell component. These findings suggest that carbocysteine promotes the repair of damaged epithelium by allergic reaction and may be useful in allergic airway diseases accompanied by isolated chronic coughing, especially eosinophilic bronchitis without asthma and tracheobronchitis with cough hypersensitivity. (+info)
Does early detection of otitis media with effusion prevent delayed language development?
(4/37)
OBJECTIVE: To consider whether earlier detection of otitis media with effusion (OME) in asymptomatic children in the first 4 years of life prevents delayed language development. METHODS: MEDLINE and other databases were searched and relevant references from articles reviewed. Critical appraisal and consensus development were in accordance with the methods of the Canadian Task Force on Preventive Health Care. RESULTS: No randomised controlled trials assessing the overall screening for OME and early intervention to prevent delay in acquiring language were identified, although one trial evaluated treatment in a screened population and found no benefit. The "analytic pathway" approach was therefore used, where evidence is evaluated for individual steps in a screening process. The evidence supporting the use of tools for early detection such as tympanometry, microtympanometry, acoustic reflectometry, and pneumatic otoscopy in the first 4 years of life is unclear. Some treatments (mucolytics, antibiotics, steroids) resulted in the short term resolution of effusions as measured by tympanometry. Ventilation tubes resolved effusions and improved hearing. Ventilation tubes in children with hearing loss associated with OME benefited children in the short term, but after 18 months there was no difference in comparison with those assigned to watchful waiting. Most prospective cohort studies that evaluated the association between OME and language development lacked adequate measurement of exposure or outcome, or suffered from attrition bias. Findings with regard to the association were inconsistent. CONCLUSIONS: There is insufficient evidence to support attempts at early detection of OME in the first 4 years of life in the asymptomatic child to prevent delayed language development. (+info)
S-carboxymethylcysteine in the treatment of glue ear: quantitative systematic review.
(5/37)
OBJECTIVE: To establish the clinical relevance of S-carboxymethylcysteine in the treatment of glue ear in children using measures approximating those saving a child from operation for grommet insertion. DATA SOURCES: Cochrane Library, MEDLINE, EMBASE, PubMed, reference lists and reviews were used for randomised controlled trials comparing S-carboxymethylcysteine with placebo. Seven trials involving 283 children and 146 ears were found. REVIEW METHODS: Studies were randomised, double-blind comparisons of S-carboxymethylcysteine (any dose and duration) with placebo in otitis media with effusion. Quality of trial reporting and validity of methods were assessed and used in sensitivity analysis. Main outcomes were relative benefit and number-needed-to-treat to prevent one grommet operation compared with placebo. RESULTS: Successful outcomes were obtained in 17% of children given placebo (range 5% to 38% in individual studies) and in 35% of children given S-carboxymethylcysteine (range 22 to 80%). For combined data (children and ears) the relative benefit was 2.0 (95%CI 1.4 to 2.8) and number-needed-to-treat 5.5 (95% confidence interval 3.8 to 9.8). Pooled data from trials of higher reporting quality (4/7) or methodological validity (3/7) tended to have lower efficacy but were not statistically different from those of lower quality or validity. CONCLUSION: S-carboxymethylcysteine is effective in the treatment of children with glue ear. For every five or six children treated with S-carboxymethylcysteine over one to three months, one will not undergo surgery for grommet insertion who would have done had they been given placebo. The confidence in this conclusion is limited because studies included relatively few children. (+info)
Insights into the mechanisms of ifosfamide encephalopathy: drug metabolites have agonistic effects on alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)/kainate receptors and induce cellular acidification in mouse cortical neurons.
(6/37)
Therapeutic value of the alkylating agent ifosfamide has been limited by major side effects including encephalopathy. Although the underlying biochemical processes of the neurotoxic side effects are still unclear, they could be attributed to metabolites rather than to ifosfamide itself. In the present study, the effects of selected ifosfamide metabolites on indices of neuronal activity have been investigated, in particular for S-carboxymethylcysteine (SCMC) and thiodiglycolic acid (TDGA). Because of structural similarities of SCMC with glutamate, the Ca(2+)(i) response of single mouse cortical neurons to SCMC and TDGA was investigated. SCMC, but not TDGA, evoked a robust increase in Ca(2+)(i) concentration that could be abolished by the alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)/kainate receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX), but only partly diminished by the N-methyl-D-aspartate receptor antagonist 10,11-dihydro-5-methyl-5H-dibenzo[a,d]cyclohepten-5,10-imine (MK=801). Cyclothiazide (CYZ), used to prevent AMPA/kainate receptor desensitization, potentiated the response to SCMC. Because activation of AMPA/kainate receptors is known to induce proton influx, the intracellular pH (pH(i)) response to SCMC was investigated. SCMC caused a concentration-dependent acidification that was amplified by CYZ. Since H(+)/monocarboxylate transporter (MCT) activity leads to similar cellular acidification, we tested its potential involvement in the pH(i) response. Application of the lactate transport inhibitor quercetin diminished the pH(i) response to SCMC and TDGA by 43 and 51%, respectively, indicating that these compounds may be substrates of MCTs. Taken together, this study indicates that hitherto apparently inert ifosfamide metabolites, in particular SCMC, activate AMPA/kainate receptors and induce cellular acidification. Both processes could provide the biochemical basis of the observed ifosfamide-associated encephalopathy. (+info)
Effect of carbocysteine on cough reflex to capsaicin in asthmatic patients.
(7/37)
AIMS: Cough, one of the main symptoms of bronchial asthma, is a chronic airway inflammatory disease with functionally damaged bronchial epithelium. Recently, we established an animal model with cough hypersensitivity after antigen challenge and clearly showed the protective effect of carbocysteine in this model. This study was designed to investigate the clinical effect of carbocysteine for cough sensitivity in patients with bronchial asthma. METHODS: The effects of the two orally active mucoregulatory drugs, carbocysteine and ambroxol hydrochloride, on cough response to inhaled capsaicin were examined in 14 patients with stable asthma. Capsaicin cough threshold, defined as the lowest concentration of capsaicin eliciting five or more coughs, was measured as an index of airway cough sensitivity. RESULTS: Geometric mean values of the cough threshold at run-in (baseline) and after 4 weeks' treatment of placebo, 1500 mg day-1 of carbocysteine and 45 mg day-1 of ambroxol hydrochloride were 12.8 micro M (95% confidence interval [CI] 5.5, 29.6), 11.0 micro M (95% CI 4.4, 27.5), 21.0 micro M (95% CI 8.8, 50.2) and 11.6 micro M (95% CI 5.8, 23.3), respectively. The cough threshold for carbocysteine was significantly greater than those of ambroxol hydrochloride (P = 0.047) and placebo (P = 0.047), respectively. CONCLUSIONS: These findings indicate that carbocysteine administration may be a novel therapeutic option for asthmatic patients, especially with cough variant asthma. (+info)
Study about the inhibition of L-cysteine derivatives of nucleic acid bases in protein production.
(8/37)
Isopoly (S-carboxymethyl-L-cysteine) derivatives of nucleic acids bases were prepared as antisense compounds. In past study, we investigated the properties of these compounds in vitro, and revealed that these compounds in vivo regulated the cell death presumably due to the inhibition of protein production. In this study, western and northern blots were carried out in order to reveal the mechanism of this inhibition for N-methyl-D-aspartate receptor in neuroblastoma x glioma hybrid NG108-15 cell line. In addition, we investigated the resistance of these compounds against cell extract and the metabolism. In conclusion, we proved that these compounds inhibited the protein production by antisense mechanism. (+info)