Biomedical subjects
Publications and source records attributed to K Koziol.
Oxidised, multi-walled, carbon nanotubes can be grafted with polystyrene molecules using an situ radical polymerisation reaction, thereby dramatically modifying their solubility and their suitability for nanocomposite applications.
Bacterial resistance to antibiotics is a significant problem in medical care facilities, causing increased fatalities due to infection. The present study demonstrates that antibiotic structures can be selectively altered in a manner that revives their ability to inhibit bacterial growth. The antibiotic tetracycline was ethylated at the position of the phenolic hydroxy group with the use of diazoethane, forming an ethyl ether functional group. This derivative was dissolved in Luria-Bertani (LB) agar medium, then placed in tissue culture for screening against a tetracycline-resistant bacterial strain. The growth of this bacterial strain, designated XL1-Blue, was inhibited by the ethylated form of tetracycline. The procedure for synthesizing ethylated tetracycline utilizes diazoethane and is presented with the molecular structures and IR spectra. The ethylated form of tetracycline was stable at -20 degrees C for many weeks, and was soluble in LB agar plate medium. Ethylated tetracycline induced growth inhibition of XL1-Blue bacteria within the first 24 h of incubation. The level of bacterial growth inhibition was greater than 30%. Calculation of the partition coefficient, log P, was accomplished and indicates that ethylated tetracycline has an increased lipophilic tendency relative to unmodified tetracycline, and therefore has greater solubility in lipid bilayers.
Bacterial resistance to antibiotics is a significant problem in health facilities and results in higher costs for health care and increased fatalities due to infection. The work presented here suggests that antibiotic molecular structure can be altered in a selected manner, which will revive the bacterial growth inhibiting capability. A bacterial strain PKK3535(DH1), which is resistant to the antibiotic ampicillin, was found to be highly growth inhibited by these altered forms of ampicillin when tested in tissue culture. The level of growth inhibition of bacterial strain PKK3535(DHI) was greater than 50%, for both molecular variants of ampicillin that were investigated. The bacteria strain used for testing was a clinical isolate obtained from the University Hospital of the University of Nebraska, Omaha. These two antibiotic variants were methylated ampicillin and ethylated ampicillin. The synthetic procedure for generating these variants is presented as well as the molecular structure. The methylated and ethylated ampicillin were found to be stable at 0 degrees C for many weeks, were somewhat less soluble than normal ampicillin, but dissolved in LB plate media. The resistant bacteria strain was plated onto LB media with altered ampicillin and profound inhibition of bacteria growth was seen within the first 24 hours of incubation. These molecular variants of ampicillin provide evidence of a means to combat the proliferation of resistant bacterial strains. The molecular alteration of antibiotics may provide a suitable means to study and combat the appearance of antibiotic-resistant bacteria.
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To provide medical service at lower costs without diminishing either quality or coverage, the District of Columbia enrolled approximately 1,000 Medicaid beneficiaries, voluntarily, in a prepaid group practice (PGP). The project was evaluated over a three-year period (1971-1974) with regard to: 1) rate of utilzation of medical care before and after enrollment; 2) costs of care per capita as compared with those of the 160,000 beneficiaries in the Medicaid fee-for-service universe; and 3) patient satisfaction with the PGP. Results indicate that for the 834 individuals aged 1 through 64 enrolled in the PGP; ambulatory physican encounter rates decreased 15 per cent, drug utilization was down 18 per cent, hospital admissions decreased 30 per cent, and hospital days declined 32 per cent after enrollment. For the same benefit package, annual prepaid per capita costs for the Medicaid PGP enrollees for 1972, 1973, 1974 were only +282, +232, and +286 respectively, representing a 37 per cent saving when compared to the fee-for-service per capita costs of the Medicaid Universe which stood of +373, +435 and +465 over the same period. The instrument used to probe patient satisfaction showed the Study Group was satisfied with the PGP, and received better dental care. The voluntary dropout rate from the PGP was only 2.5 per cent; and out-of-plan utilization was low, indicating good acceptance of the PGP service.