An Investigation into the Fate of Benzylpenicillin and its Degradation Compounds in Milk Following Intramammary Treatments for Bovine Mastitis

The presence of antibiotics in bovine milk results mainly from the treatment of mastitis by intramammary infusion. The sale of this contaminated milk is illegal and the milk supply is routinely tested for adulteration by antibiotic residues. At present these tests are unspecific microbiological assays which detect only inhibitory substances and consequently the presence of any inactive degradation compounds is not tested for. Various chromatographic approaches exist in the literature which report the resolution of mixtures of antibiotic compounds from milk. However, the presence of antibiotic degradation residues in milk, which may have serious implications for the health of the consumer, has not been studied. Benzylpenicillin is the antibiotic responsible for most failures of the regulatory tests and is present in the majority of common mastitis treatments. Although often administered as the procaine salt it degrades rapidly, especially in the presence of P-lactamase enzymes produced by resistant strains of bacteria. This thesis initially describes the development of a chromatographic system for the detection and separation of benzylpenicillin and its major degradation compounds in aqueous solution. HPLC and the relatively recently developed technique of Micellar Electrokinetic Capillary Chromatography (MECC) were both successfully employed to perform this function. An important part of the research, however, was the development of an efficient milk extraction and sample clean up technique, complicated by the complexity of the milk matrix and also the instability of benzylpenicillin. HPLC was found to be unsuitable for the resolution of the degradation compounds from milk because of background interference despite extensive sample clean up by methods reported in the literature and developed during the course of this work. MECC on the other hand provided the necessary resolution for the detection of these compounds without the need for extensive sample manipulation. The final novel procedure was a combination of acetonitrile extraction coupled with solid phase clean up which took into consideration the presence of proteins, carbohydrates and lipids; the major constituents of the milk matrix. The preparation and identification of the major aqueous degradation compounds of benzylpenicillin was achieved and confirmed by NMR and FTIR studies. The action of β-lactmases (penicillinase) on penicillin to produce benzylpenicilloic acid and its subsequent epimerisation from the 5R,6R diastereoisomer to the 5S,6R epimer is also reported. Once the optimum milk extraction and purification methods had been found, they were applied to milk collected from cows treated for mastitis with two different infusions containing benzylpenicillin. From these in-vivo samples it was apparent that only one penicillin degradation compound, 5R,6R benzylpenicilloic acid, was present in milk following intramammary treatment. When the benzylpenicillin was administered as the procaine salt the benzylpenicilloic acid was detectable in the milk during the entire 72 hour withdrawal period

A cost-benefit analysis of introducing and anethesia residency electrive at a private health system

The United States is facing a physician shortage of immense proportions in the future, with an estimated shortage of approximately 37,800 - 124,000 physicians by 2034. In an effort to increase graduate medical education opportunities, some private health systems in the US have sponsored residency elective rotations in conjunction with academic medical centers. Anesthesiology electives in a private health system are unique in that they may have an impact on the clinical productivity of the private anesthesiologists. Out goal was to explore the financial costs associated with establishing a one-month anesthesiology residency elective rotation at a private health system, as well as identify potential benefits to the academic center, residents, and the private health system

A cost-benefit analysis of introducing and anesthesia residency elective at a private health system

The United States is facing a physician shortage of immense proportions in the future, with an estimated shortage of approximately 37,800-124,000 physicians by 2034.1 In an effort to increase graduate medical education opportunities, some private health systems in the US have sponsored residency elective rotations in conjunction with academic medical centers. Anesthesiology electives in a private health system are unique in that they may have an impact on the clinical productivity of the private anesthesiologists. Our goal was to explore the financial costs associated with establishing a one-month anesthesiology residency elective rotation at a private health system, as well as identify potential benefits to the academic center, residents, and the private health system

Dismembered: Native Disenrollment and the Battle for Human Rights

While the number of federally recognized Native nations in the United States are increasing, the population figures for existing tribal nations are declining. This depopulation is not being perpetrated by the federal government, but by Native governments that are banishing, denying, or disenrolling Native citizens at an unprecedented rate. Since the 1990s, tribal belonging has become more of a privilege than a sacred right. Political and legal dismemberment has become a national phenomenon with nearly eighty Native nations, in at least twenty states, terminating the rights of indigenous citizens.The first comprehensive examination of the origins and significance of tribal disenrollment, Dismembered examines this disturbing trend, which often leaves the disenrolled tribal members with no recourse or appeal. At the center of the issue is how Native nations are defined today and who has the fundamental rights to belong. By looking at hundreds of tribal constitutions and talking with both disenrolled members and tribal officials, the authors demonstrate the damage this practice is having across Indian Country and ways to address the problem.https://scholarship.richmond.edu/bookshelf/1328/thumbnail.jp

The Effect of the Form of Tax Incentives on Individuals’ Savings Decisions

Congress and the media have both expressed concerns about Americans’ low savings rates. We address these concerns by investigating the extent to which the form of an investment’s tax preference affects individuals’ willingness to choose a tax-preferred vehicle over a less restrictive, but non-tax-preferred, investment. Specifically, we tested the extent to which subjects chose a traditional savings plan versus an investment resembling either a traditional IRA, Roth IRA, or government matching program. We find that subjects are not as sensitive to the form of the tax preference as they are to restrictions on their ability to withdraw funds. This suggests that, by reconsidering the extent to which individuals are forced to trade off tax savings and liquidity restrictions, Congress might more effectively promote individuals’ retirement savings

Peripheral Galanin Receptor 2 as a Target for the Modulation of Pain

The neuropeptide galanin is widely expressed in the nervous system and has an important role in nociception. It has been shown that galanin can facilitate and inhibit nociception in a dose-dependent manner, principally through the central nervous system, with enhanced antinociceptive actions after nerve injury. However, following nerve injury, expression of galanin within the peripheral nervous system is dramatically increased up to 120-fold. Despite this striking increase in the peripheral nervous system, few studies have investigated the role that galanin plays in modulating nociception at the primary afferent nociceptor. Here, we summarise the recent work supporting the role of peripherally expressed galanin with particular reference to the dual actions of the galanin receptor 2 in neuropathic pain highlighting this as a potential target analgesic

A comparative study of major element rock analyses by argon plasma emission and atomic absorption/emission spectrophotometry.

Dept. of Geology and Geological Engineering. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1978 .Q957. Source: Masters Abstracts International, Volume: 40-07, page: . Thesis (M.A.Sc.)--University of Windsor (Canada), 1978