Deazapurine Nucleoside Analogues for the Treatment of Trichomonas vaginalis.

Trichomoniasis is the most common nonviral sexually transmitted disease in humans, but treatment options are limited. Here, we report a resorufin-based drug sensitivity assay for high-throughput microplate-based screening under hypoxic conditions. A 5203-compound enamine kinase library and several specialized compound series were tested for the inhibition of Trichomonas growth at 10 µM with Z' values of >0.5. Hits were rescreened in serial dilution to establish an IC50 concentration. A series of 7-substituted 7-deazaadenosine analogues emerged as highly potent anti-T. vaginalis agents, with EC50 values in the low double digit nanomolar range. These analogues exhibited excellent selectivity indices. Follow-up medicinal chemistry efforts identified an optimal ribofuranose and C7 substituent. Several nucleosides rapidly cleared cultures of T. vaginalis at a concentrations of just 2 × EC50. Preliminary in vivo evaluation in a murine trichomoniasis model (Tritrichomonas foetus) revealed promising activity upon topical administration, validating purine nucleoside analogues as a new class of antitrichomonal agents.

Chaplain rounds: a chance for medical students to reflect on spirituality in patient-centered care.

OBJECTIVE: This study assesses the perceived impact of a required half-day with a hospital chaplain for first-year medical students, using a qualitative analysis of their written reflections. METHODS: Students shadowed chaplains at the UCLA hospital with the stated goal of increasing their awareness and understanding of the spiritual aspects of health care and the role of the chaplain in patient care. Participation in the rounds and a short written reflection on their experience with the chaplain were required as part of the first-year Doctoring course. RESULTS: The qualitative analysis of reflections from 166 students using grounded theory yielded four themes: (1) the importance of spiritual care, (2) the chaplain's role in the clinical setting, (3) personal introspection, and (4) doctors and compassion. CONCLUSIONS: Going on hospital rounds with a chaplain helps medical students understand the importance of spirituality in medicine and positively influences student perceptions of chaplains and their work.

Relationship between medical student perceptions of mistreatment and mistreatment sensitivity.

BACKGROUND: National statistics reveal that efforts to reduce medical student mistreatment have been largely ineffective. Some hypothesize that as supervisors gain skills in professionalism, medical students become more sensitive. AIMS: The purpose of this study was to determine if medical student perceptions of mistreatment are correlated with mistreatment sensitivity. METHOD: At the end of their third year, 175 medical students completed an Abuse Sensitivity Questionnaire, focused on student assessment of hypothetical scenarios which might be perceived as abusive, and the annual Well-Being Survey, which includes measurement of incident rates of mistreatment. It was hypothesized that those students who identified the scenarios as abusive would also be more likely to perceive that they had been mistreated. RESULTS: Student perceptions of mistreatment were not statistically correlated with individual's responses to the scenarios or to a statistically derived abuse sensitivity variable. There were no differences in abuse sensitivity by student age or ethnicity. Women were more likely than men to consider it "harsh" to be called incompetent during rounds (p < 0.0005). CONCLUSION: This study provides preliminary evidence that challenges the hypothesis that medical students who perceive mistreatment by their superiors are simply more sensitive.

Educational Experiences Residents Perceive As Most Helpful for the Acquisition of the ACGME Competencies.

BACKGROUND: The Accreditation Council for Graduate Medical Education (ACGME) requires physicians in training to be educated in 6 competencies considered important for independent medical practice. There is little information about the experiences that residents feel contribute most to the acquisition of the competencies. OBJECTIVE: To understand how residents perceive their learning of the ACGME competencies and to determine which educational activities were most helpful in acquiring these competencies. METHOD: A web-based survey created by the graduate medical education office for institutional program monitoring and evaluation was sent to all residents in ACGME-accredited programs at the David Geffen School of Medicine, University of California-Los Angeles, from 2007 to 2010. Residents responded to questions about the adequacy of their learning for each of the 6 competencies and which learning activities were most helpful in competency acquisition. RESULTS: We analyzed 1378 responses collected from postgraduate year-1 (PGY-1) to PGY-3 residents in 12 different residency programs, surveyed between 2007 and 2010. The overall response rate varied by year (66%-82%). Most residents (80%-97%) stated that their learning of the 6 ACGME competencies was "adequate." Patient care activities and observation of attending physicians and peers were listed as the 2 most helpful learning activities for acquiring the 6 competencies. CONCLUSION: Our findings reinforce the importance of learning from role models during patient care activities and the heterogeneity of learning activities needed for acquiring all 6 competencies.

Outer membrane protein A of bovine and ovine isolates of Mannheimia haemolytica is surface exposed and contains host species-specific epitopes.

Mannheimia haemolytica is the etiological agent of pneumonic pasteurellosis of cattle and sheep; two different OmpA subclasses, OmpA1 and OmpA2, are associated with bovine and ovine isolates, respectively. These proteins differ at the distal ends of four external loops, are involved in adherence, and are likely to play important roles in host adaptation. M. haemolytica is surrounded by a polysaccharide capsule, and the degree of OmpA surface exposure is unknown. To investigate surface exposure and immune specificity of OmpA among bovine and ovine M. haemolytica isolates, recombinant proteins representing the transmembrane domain of OmpA from a bovine serotype A1 isolate (rOmpA1) and an ovine serotype A2 isolate (rOmpA2) were overexpressed, purified, and used to generate anti-rOmpA1 and anti-rOmpA2 antibodies, respectively. Immunogold electron microscopy and immunofluorescence techniques demonstrated that OmpA1 and OmpA2 are surface exposed, and are not masked by the polysaccharide capsule, in a selection of M. haemolytica isolates of various serotypes and grown under different growth conditions. To explore epitope specificity, anti-rOmpA1 and anti-rOmpA2 antibodies were cross-absorbed with the heterologous isolate to remove cross-reacting antibodies. These cross-absorbed antibodies were highly specific and recognized only the OmpA protein of the homologous isolate in Western blot assays. A wider examination of the binding specificities of these antibodies for M. haemolytica isolates representing different OmpA subclasses revealed that cross-absorbed anti-rOmpA1 antibodies recognized OmpA1-type proteins but not OmpA2-type proteins; conversely, cross-absorbed anti-rOmpA2 antibodies recognized OmpA2-type proteins but not OmpA1-type proteins. Our results demonstrate that OmpA1 and OmpA2 are surface exposed and could potentially bind to different receptors in cattle and sheep.

Integrating case topics in medical school curriculum to enhance multiple skill learning: using fetal alcohol spectrum disorders as an exemplary case.

OBJECTIVES: This article describes the use of fetal alcohol spectrum disorders (FASDs) as a theme to connect the learning of basic neurosciences with clinical applications across the age span within a systems-based, integrated curricular structure that emphasizes problem-based learning. METHODS: In collaboration with the Centers for Disease Control and Prevention (CDC) and the National Organization on Fetal Alcohol Syndrome, the Western Regional Training Center for Fetal Alcohol Exposure at UCLA developed and integrated educational materials on FASDs into the curriculum for first-year medical students. RESULTS: Quantitative and qualitative evaluations suggested materials were effective in enhancing student knowledge and skills related to FASDs, as well as embryology, brain development, substance abuse, developmental psychopathology, and medical ethics. CONCLUSION: The use of a unifying theme integrating basic science and clinical information and skills is effective for medical student training in the prevention and treatment of common medical problems.

Adjuvant effects of adenylate cyclase toxin of Bordetella pertussis after intranasal immunisation of mice.

This study examined the ability of the adenylate cyclase toxin (CyaA) of Bordetella pertussis to act as a mucosal adjuvant for other antigens when co-administered by the intranasal route in mice. Two forms of CyaA were used: the cell-invasive, enzymically active form and a cell-invasive toxin lacking adenylate cyclase enzymic activity (CyaA*). Co-administration intranasally (i/n) of CyaA or CyaA* with ovalbumin (Ova) significantly enhanced (P<0.05) anti-Ova IgG and IgA antibody responses in the serum and anti-Ova IgA responses in lung and nasal secretions compared to those generated by immunisation i/n with Ova alone. The effects were greater with CyaA*. Administration of CyaA* with Ova induced priming of Ova-specific T cells in vivo to a greater extent than that obtained after immunisation with Ova alone. Co-administration of CyaA or CyaA* with pertactin (Prn) significantly enhanced (P<0.05) the serum anti-Prn IgG responses and immunisation with Prn and CyaA* significantly increased the anti-Prn IgA responses in the lungs compared with responses after immunisation with Prn alone. Immunisation i/n with Prn alone partially protected mice (P<0.05) against challenge i/n with B. pertussis. Co-administration of CyaA or CyaA* with pertactin (Prn) significantly increased protection (P<0.05) against challenge compared to that obtained with Prn alone. These effects were particularly apparent with CyaA* as the adjuvant.

An innovative program to augment community preceptors' practice and teaching skills.

Medical students currently interface more and more with community-based physicians, many of whom have little training or experience as educators. They also start their ambulatory experiences from the beginning of their medical school training, not just at the clerkship year. This has prompted substantial literature on the need for improved faculty development for community preceptors, which is widely believed to be inadequate at present. The authors describe a novel program, designed to augment community preceptor teaching skills and practice behaviors, focusing on topics relating to humanism, communication, and psychosocial issues common in primary care. The program was conducted for four years beginning in 1999 and organized around acknowledged attributes of successful adult learning, and used case-based, small-group sessions, where individual community preceptors were each asked to "teach" a series of standardized students, in front of the group, regarding issues raised by a number of hypothetical patient cases. The standardized students had in turn been trained by the authors to interact with the participating faculty in a defined manner. The small-group sessions were led by community "opinion leaders" who had been chosen for this role by the participants, and who themselves first underwent training by the authors to familiarize them with core concepts felt to be essential to the program. At the conclusion of the entire process, surveys of the opinion leaders, the other community preceptor participants, and the standardized students suggested that the program did stimulate significant changes in attitude and behavior, although further research is needed to confirm this.

Adjuvanticity of native and detoxified adenylate cyclase toxin of Bordetella pertussis towards co-administered antigens.

The cell-invasive adenylate cyclase toxin (CyaA) of Bordetella pertussis was shown to be highly antigenic in mice, stimulating serum anti-CyaA IgG antibody responses which were able to neutralise the cytotoxic effect of CyaA on J774.2 macrophage-like cells. The effect of co-administration to mice of the fully functional CyaA toxin or a toxin lacking adenylate cyclase enzymic activity (CyaA*) with other antigens from B. pertussis, namely pertussis toxin (PT) or pertussis toxoid (PTd), filamentous haemagglutinin (FHA) and pertactin (PRN), was investigated. CyaA* enhanced the serum IgG antibody responses to each of these antigens whereas, with CyaA, only anti-PRN antibody titres showed a modest increase. Peritoneal macrophages and spleen cells, collected at 2 weeks post-immunisation, were cultured and tested for nitric oxide (NO) and IFNgamma production, respectively, after stimulation in vitro with heat-killed B. pertussis cells or CyaA proteins. NO and IFNgamma production were higher in cells collected from mice immunised with CyaA or CyaA* in combination with a PT, FHA and PRN antigen mixture than from those taken from mice injected with antigen mixture alone, again with CyaA* acting as a better adjuvant than CyaA. The apparent enhancement of immune responses to the antigen mixture by CyaA* in particular was not paralleled by increased protection of mice against aerosol challenge with B. pertussis, but a statistically significant increase in protection was seen after intranasal challenge with B. parapertussis.

Self-instructional "virtual pathology" laboratories using web-based technology enhance medical school teaching of pathology.

Second-year medical students have traditionally been taught pulmonary pathophysiology at the University of California-Los Angeles (UCLA) School of Medicine using lectures, discussion groups, and laboratory sessions. Since 1998, the laboratory sessions have been replaced by 4 interactive, self-instructional sessions using web-based technology and case-based instruction. This article addresses nature of transformation that occurred from within the course in response to the infusion of new technologies. The vast majority of the course content has been digitized and incorporated into the website of the Pathophysiology of Disease course. The teaching histological slides have been photographed digitally and organized into "cases" with clinical information, digital images and text, and audio descriptions. The students study the materials from these cases at their own pace in 2 "virtual pathology" laboratory, with a few instructors supervising the on-site sessions. The students discuss additional cases available on the website in 2 other laboratory sessions supervised by a pulmonologist and a pathologist. Marked improvement in student participation and satisfaction was seen with the use of web-based instruction. Attendance at laboratory sessions, where the students had previously been required to bring their own microscopes to study histological slides at their own pace, increased from approximately 30% to 40% of the class in previous years to almost 100%. Satisfaction surveys showed progressive improvement over the past 4 years, as various suggestions were implemented. The value of web-based instruction of pathology at the UCLA School of Medicine is discussed.

Cytotoxic activity of Mannheimia haemolytica strains in relation to diversity of the leukotoxin structural gene lktA.

The leukotoxin of Mannheimia haemolytica has a very high degree of amino acid diversity because the lktA gene has a complex mosaic structure that has been derived by horizontal DNA transfer and intragenic recombination. The objective of the present study was to determine the effect of this amino acid diversity on leukotoxin cytotoxicity against bovine and ovine cell types. This was done by comparing the luminol-dependent chemiluminescence response of bovine and ovine neutrophils after pre-incubation with the various leukotoxin types. The LktA1.1-type leukotoxin associated with bovine serotype A1 and A6 strains differs from the LktA1.2-type leukotoxin produced by ovine serotype A1 and A6 strains at a single amino acid position and has enhanced activity against bovine but reduced activity against ovine neutrophils. These findings, together with the exclusive association of the LktA1.1-type leukotoxin with bovine strains, suggest that this leukotoxin type has an adaptive advantage in the bovine host. Leukotoxins LktA6-LktA10 are associated with ovine strains and have complex mosaic structures and diverse amino acid sequences but similar levels of cytotoxic activity against bovine and ovine neutrophils, respectively. However, ovine neutrophils were more sensitive to the cytotoxic activities of these leukotoxins than were bovine neutrophils. LktA8- and LktA10-type leukotoxins are associated with serotype A2 and A7 strains that are responsible for the majority of ovine disease cases, but LktA6-, LktA7- and LktA9-type leukotoxins are associated with less common serotypes. These findings contribute to the growing body of evidence suggesting that factors other than leukotoxin cytotoxicity are responsible for the full expression of virulence in M. haemolytica. Overall, the extensive recombinational exchanges within the lktA gene of M. haemolytica have had little effect on leukotoxin function which is highly conserved.

Characterization and comparison of Pasteurella multocida strains associated with porcine pneumonia and atrophic rhinitis.

One hundred and fifty-eight porcine strains of Pasteurella multocida, recovered primarily from cases of pneumonic pasteurellosis or progressive atrophic rhinitis (PAR) in England and Wales, were characterized by determination of their capsular types, presence or absence of the toxA gene and molecular mass heterogeneity of the heat-modifiable (OmpA) and porin (OmpH) proteins. Eighteen groups (clones) of strains were identified on the basis of specific combinations of capsular type, toxA status and outer-membrane protein (OMP)-type. The data provided evidence that different subpopulations of P. multocida are responsible for pneumonia and PAR in pigs. The majority (88 %) of cases of pneumonia were associated exclusively with non-toxigenic capsular type A strains of OMP-types 1.1, 2.1, 3.1 and 5.1 and capsular type D isolates of OMP-type 6.1. These strains were recovered from widespread geographical locations within England and Wales over a 12-year period and represented mostly single sporadic cases. The association of a small number of P. multocida variants with the majority of cases of porcine pneumonia suggests that these strains are not opportunistic pathogens of low virulence but represent primary pathogens with a relatively high degree of virulence. In contrast, the majority (76 %) of cases of PAR were associated with toxA-containing capsular type D strains of OMP-type 4.1 and capsular type A and D strains of OMP-type 6.1. Toxigenic capsular type A strains associated with PAR and non-toxigenic capsular type A strains associated with pneumonia represent distinct subpopulations of P. multocida that can be differentiated by their OMP-types. The association of capsular types A and D with strains of the same OMP-types, and the absence and presence of the toxA gene in strains of the same OMP-types, suggest that horizontal transfer of capsular biosynthesis and toxA genes has occurred between strains representing certain subpopulations of P. multocida.