Successful Immunization of an Allogeneic Bone Marrow Transplant Recipient with Live, Attenuated Yellow Fever Vaccine

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75383/1/j.1708-8305.2009.00336.x.pd

The Reply

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/30359/1/0000761.pd

Progress in the pathogenesis of Legionella pneumophila

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/29516/1/0000603.pd

PhoA gene fusions in Legionella pneumophila generated in vivo using a new transposon, MudphoA

To enable effective use of phoA gene fusions in Legionella pneumophila , we constructed MudphoA , a derivative of the mini-Mu phage Mu dII4041, which is capable of generating gene fusions to the Escherichia coli alkaline phosphatase gene (EC 3.1.3.1). Although an existing fusion-generating transposon, TnphoA , has been a useful tool for studying secreted proteins in other bacteria, this transposon and other Tn 5 derivatives transpose inefficiently in Legionella pneumophila , necessitating the construction of a more effective vector for use in this pathogen. Using MudphoA we generated fusions to an E. coli gene encoding a periplasmic protein and to an L. pneumophila gene encoding an outer membrane protein; both sets of fusions resulted in alkaline phosphatase activity. We have begun to use MudphoA to mutate secreted proteins of L. pneumophila specifically, since this subset of bacterial proteins is most likely to be involved in host-bacterial interactions. This modified transposon may be useful for studies of other bacteria that support transposition of Mu, but not Tn 5 , derivatives.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75760/1/j.1365-2958.1992.tb01355.x.pd

Growth of Legionella pneumophila in a human macrophage-like (U937) cell line

We established a model of the bacteria-macrophage interaction to study the cellular basis of Legionella pneumophila pathogenesis and to characterize avirulent L. pneumophila. We found that U937 cells, which are derived from a human histiocytic lymphoma cell line, support intracellular growth of L. pneumophila with a doubling time of 6 h, and that sustained intracellular growth is associated with a cytopathic effect (CPE) that can be detected by microscopic examination and quantified with the vital stain 3-(4,5-dimethyl thiazol-2-yl)-2,5,-diphenyl tetrazolium bromide (MTT). An L. pneumophila isolate obtained directly from infected guinea-pig spleens can grow and produce CPE in these cells, destroying most of the cell layer after 72 h of growth. Only 106 organisms of this strain are required to kill 50% of guinea-pigs inoculated by the intraperitoneal route. In contrast, an avirulent isolate derived by 203 successive plate passages of the same strain can neither kill guinea-pigs at an intraperitoneal inoculum of 107 nor grow or produce CPE in U937 cells. Since the cells were able to differentiate between a virulent and an avirulent strain of L. pneumophila, we conclude that U937 cells are an appropriate model system for study of the bacteria-macrophage interaction.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/27184/1/0000187.pd

Transfer and maintenance of small, mobilizable plasmids with ColE1 replication origins in Legionella pneumophila

With the mutagenesis of specific, virulence-associated genes of Legionella pneumophila as the eventual goal, methods for gene transfer to these bacteria were developed. Following the observations of others that conjugative, broad-host-range plasmids could be transferred from Escherichia coli to L. pneumophila at low frequency, we constructed a small mobilizable vector, pTLP1, which carries oriV from pBR322, oriT from pRK2, Kmr from Tn5, and an L. pneumophila-derived fragment to permit chromosomal integration. In triparental matings including an E. coli with a conjugative (Tra+) helper plasmid, kanamycin-resistance was transferred from E. coli to L. pneumophila. Southern hybridization of L. pneumophila transconjugants showed that pTLP1 was replicated autonomously. Additional matings of plasmids having deletions or substitutions of pTLP1 sequences confirmed that replication in L. pneumophila requires oriV only. pTLP1 was maintained in L. pneumophila with passage on medium containing kanamycin but was rapidly lost after passage on nonselective medium. This plasmid instability in L. pneumophila is most likely due to rapid generation of plasmid-free segregants because of plasmid multimerization and low plasmid copy number. We conclude that mobilizable pBR322-derived plasmids can be used as shuttle vectors to transfer cloned genes to L. pneumophila, a feature that can be exploited for the purposes of mutagenesis or genetic complementation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/27233/1/0000240.pd

Online learning applied to a course on rational therapeutics: an international comparison between final year students of two medical schools

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/96234/1/bcp4370.pd

Seasonal symptom variation in patients with chronic fatigue: Comparison with major mood disorders

The psychobiology of idiopathic fatigue has received renewed interest in the medical literature in recent years. In order to examine the relation between chronic, idiopathic fatigue and specific subtypes of depressive illness, we characterized the pattern and severity of seasonal symptom variation in 73 patients with chronic, idiopathic fatigue, compared to patients with major depression (n = 55), a typical depression (n = 35), and seasonal affective disorder (n = 16). Fifty of the fatigued subjects also met the specific Centers for Disease Control and Prevention case criteria for chronic fatigue syndrome, though this definition was unable to discriminate a distinct subgroup of patients, based on their seasonality scores alone. As a group, the fatigued subjects reported the lowest levels of symptom seasonality of any of the study groups. Further, even in those fatigued subjects with scores in the range of those seen in patients with seasonal affective disorder, seasonality was not reported to be a subjectively distressing problem. These findings lend support to the idea that although chronic fatigue shares some clinical features with certain mood disorders, they are not the same illnesses. These data are also consistent with the emerging view that chronic fatigue represents a heterogeneously determined clinical condition.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/31850/1/0000799.pd

Site-specific mutagenesis in Legionella pneumophila by allelic exchange using counterselectable ColE1 vectors

To study the molecular pathogenesis of infection by Legionella pneumophila, a technique of site-specific mutagenesis by allelic exchange was evaluated. To develop this system, we optimized conjugal DNA transfer by isolating a mutant that functions 1000-fold more efficiently as a recipient than the wild type strain, identified two counter-selectable markers, rpsL and sacB, that function in L. pneumophila, and constructed a counterselectable Co1E1 vector. Allelic exchange of a L. pneumophila chrosomal gene was achieved at a frequency of 10-5 per transconjugant. The allelic exchange procedure itself did not alter the ability of L. pneumophila to infect macrophages, indicating that the system can be used to study this aspect of virulence.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/27030/1/0000018.pd

Developing a fully online course for senior medical students

In 2002 the University of Michigan Medical School created a one-month course in advanced medical therapeutics (AMT). All senior medical students were required to complete the course. To provide some flexibility for students who were interviewing for residency positions the AMT course was created using a distance-learning model, and in the 2008–2009 academic year it was offered in a fully online format. The components of the course are weekly case-based modules, a weekly online seminar, quizzes based on modules and seminars, and a research project based on a therapeutic question. The paper discusses the development and components of the AMT course, a survey of fourth-year medical students who participated in the course between 2007 and 2010, and how the course evolved over three years