Helping Scholars Overcome Socioeconomic Barriers to Medical and Biomedical Careers: Creating a Pipeline Initiative.

Problem: To achieve their potential in medical and biomedical careers, students (scholars) from under-resourced backgrounds must build sophisticated skills and develop confidence and professionalism. To flourish in an advanced educational system that may be unfamiliar, these scholars also need networks of mentors and role models. These challenges can affect scholars at multiple stages of their education. Intervention: To meet these challenges, we created a broad and innovative biomedical research-focused pipeline program: the Johns Hopkins Initiative for Careers in Science in Medicine (CSM Initiative). This initiative targets three levels: high school, undergraduate, and post-baccalaureate/pre-doctoral (graduate and medical). We provide training in essential academic, research, professional, and social skills to meet the unique challenges of our scholars from under-resourced backgrounds. Scholars also build relationships with mentors who provide career guidance and support. We present an overview of the training and assessment at each level of this initiative. Context: The initiative took place at an institution located in the greater Baltimore area and that is endowed with exceptional doctoral and postdoctoral trainees, staff, and faculty including clinicians, physician-scientists, and scientists who served as key role models and mentors. Our pipeline program draws from local high school students and a local and national pool of undergraduates and post-baccalaureates preparing for medical or graduate school. Impact: Our goals for the high school scholars are significant improvement in academic skills, increased confidence, and matriculation into higher education systems. Currently, at least 83% of high school scholars have matriculated into four-year college programs and 73% have chosen science, technology, engineering, math, and medicine (STEMM)-related majors. Among undergraduate participants, 42% have matriculated thus far into medical or biomedical graduate programs and this number is expected to rise as more scholars graduate from college and either enter graduate training or pursue STEMM careers. Another 25% have returned to our post-baccalaureate program. Among post-baccalaureate scholars, 71% have now matriculated into doctoral-level graduate biomedical programs (medical or graduate school) and the remaining 29% are pursuing careers in STEMM-related fields such as biomedical research with some still aiming at graduate-level education. Our long-term goal is to see a large majority of our scholars become successful professionals in medicine, biomedical research, allied healthcare, or other STEMM fields. Analysis of the early phases of the CSM initiative demonstrates such outcomes are attainable. Lessons Learned: This program provides experiences in which scholars develop and practice core competencies essential for developing their self-identity as scientists and professionals. The most important lesson learned is that mentorship teams must be highly dynamic, flexible, thoughtful, and personal in responding to the wide range of challenges and obstacles that scholars from under-resourced backgrounds must overcome to achieve career success.

Inflammation-associated pathologies in a case of prostate schistosomiasis: Implications for a causal role in prostate carcinogenesis.

BACKGROUND: Urogenital infection with Schistosoma haematobium is a risk factor for the development of squamous cell carcinoma of the urinary bladder. The pathophysiology is thought to be mediated in part by inflammation, cellular damage, and bladder regeneration induced by the parasitic infection. Herein, we report an unusual case of schistosomiasis of the prostate that was found concurrent with prostate adenocarcinoma in a radical prostatectomy specimen from a man in the United States. METHODS: The infecting Schistosoma species was characterized via histomorphology and acid-fast stain. The concurrent Gleason score 6 prostate cancer was assessed for ETS transcription factor ERG (ERG), phosphatase and tensin homolog (PTEN), p27, and p53 status using immunohistochemistry (IHC). Cellular proliferation and the presence of intermediate cells in prostatic atrophy were assessed via immunostaining for Ki67 and CK903, respectively. RESULTS: Histomorphology and acid-fast stain of the infecting species were consistent with S. haematobium. We classified the Gleason score 6 prostate adenocarcinoma via IHC as ERG positive, PTEN intact, p27 intact, and without p53 nuclear accumulation. The prostatic epithelium immediately adjacent to the schistosomiasis-related granulomatous inflammation was atrophic and accompanied by increased cellular proliferation and the presence of intermediate cells. Upon literature review, we determined that prostate schistosomiasis is associated with a young age of prostate cancer diagnosis and highly aggressive prostate cancer. CONCLUSIONS: This is a rare case of prostate schistosomiasis in the United States; however, prostate schistosomiasis occurs frequently in endemic areas. The patient had traveled to a Schistosoma-endemic region, which was the likely location of exposure to the parasite. To our knowledge, this is the first report of the association of proliferative inflammatory atrophy and intermediate cells with schistosomiasis of the prostate. We propose that prostate schistosomiasis may be considered as a risk factor for the development of prostate cancer in geographic regions where Schistosoma species are endemic.

Swarming and Aggregation in the Parasitic Diplomonad Flagellate Spironucleus vortens.

Pathogenicity, evolutionary history, and unusual cell organization of diplomonads are well known, particularly for Giardia and Spironucleus; however, behavior of these aerotolerant anaerobes is largely unknown. Addressing this deficit, we studied behavior of the piscine diplomonad Spironucleus vortens (ATCC 50386) in in vitro culture. Spironucleus vortens trophozoites from Angelfish, Pterophyllum scalare, were maintained axenically in modified liver digest, yeast extract, and iron (LYI) medium, at 22 °C in the dark, and subcultured weekly. Cultures were monitored every 1-2 d, by removing an aliquot, and loading cells into a hemocytometer chamber, or onto a regular microscope slide. We observed three distinct swimming behaviors: (i) spontaneous formation of swarms, reaching 200 µm in diameter, persisting for up to several min in situ, (ii) directional movement of the swarm, via collective motility, and (iii) independent swimming of trophozoites to form a band (aggregation), presumably at the location of optimal environmental conditions. These behaviors have not previously been reported in Spironucleus. The observation that flagellate motility can change, from individual self-propulsion to complex collective swarming motility, prompts us to advocate S. vortens as a new model for study of group behavioral dynamics, complementing emerging studies of collective swimming in flagellated bacteria.

KUDOA SP. (Myxozoa: Multivalvulida) in skeletal muscle of captive bullnose eagle rays, Myliobatis freminvillei (Rajiformes: Myliobatidae).

Kudoa spp. (Myxozoa: Multivalvulida) are of significant concern in marine and estuarine teleosts because of trophozoites and spores in the skeletal muscle reducing the marketability of wild and cultured fish. Kudoa spp. have rarely been reported from elasmobranchs. Spores of a Kudoa sp. were identified in two captive, mature bullnose eagle rays (Myliobatisfreminvillei) (Rajiformes: Myliobatidae). The male bullnose eagle ray (case 1) showed intractable weight loss, muscle wasting, and hyperkalemia, and was euthanized. The skeletal muscle showed myofiber degeneration, vacuolation, and necrosis, and spores of a Kudoa sp. were present multifocally through the muscle. The female bullnose eagle ray (case 2) had a severe, rapidly progressive, erosive lesion extending through the pectoral fin and was euthanized. Spores of a Kudoa sp. were not found in the lesion but were present in two disparate sections of skeletal muscle. There was no inflammation or degeneration associated with the infected myofibers in case 2. From case 1, morphometrics of 15 spores in histologic section were apical width 6.5-8.0 µm, apical thickness 5.0-7.0 µm, lateral width 5.5-6.5 µm, length 4.5-6.5 µm; the equal-sized polar capsules were spherical, 1.5-2.5 µm in diameter; there was a clear halo 2 µm thick around the spores, considered to be a mucous envelope. Spores from case 2 were indistinguishable from those in case 1. This appears to be the first report of Kudoa sp. in bullnose eagle rays.

Intestinal pH profile in rainbow trout Oncorhynchus mykiss and microhabitat preference of the flagellate Spironucleus salmonis (Diplomonadida).

In farmed rainbow trout Oncorhynchus mykiss, the flagellate Spironucleus salmonis (Diplomonadida) is often found in the pyloric region of the intestine. While previous in vitro studies report a pH of 7.5 to 8.0 as optimal for presumed S. salmonis, no previous in vivo studies have investigated the relationship between pH and microhabitat preference. Therefore, in 698 rainbow trout (75% were 5 to 6 mo old juveniles, 10 to 20 cm total length), we recorded occurrence and density of S. salmonis, and pH, in the pyloric, anterior, middle, and posterior intestine. There were no significant differences in total length or weight between infected and uninfected fish. S. salmonis preferred the pyloric region, with occurrence and density decreasing significantly from pyloric to posterior regions. In infected fish, pH in pyloric (6.8 to 7.9, mean 7.3) and posterior regions (6.5 to 8.0, mean 7.1) was significantly lower than in anterior (6.5 to 8.5, mean 7.7) and middle (6.8 to 8.2, mean 7.7) regions; in uninfected fish, the pH profile was similar. At the individual level, 90 % of infected fish and 79% of uninfected fish showed this pH profile. In the pyloric region, pH was not significantly different among uninfected fish, and fish with light, moderate, or heavy infections. Our in vivo study suggests the optimal pH for S. salmonis is between 7.1 and 7.5, possibly close to 7.3 (the mean in pyloric region of infected fish). We conclude that while the presence of S. salmonis reflected tolerable pH, density of infection was not correlated with pH, and thus a causal relationship between microhabitat preference and pH is unlikely.

Ultrastructure and molecular diagnosis of Spironucleus salmonis (Diplomonadida) from rainbow trout Oncorhynchus mykiss in Germany.

Diplomonad flagellates infect a wide range of fish hosts in aquaculture and in the wild in North America, Asia and Europe. Intestinal diplomonad infection in juvenile farmed trout can be associated with morbidity and mortality, and in Germany, diplomonads in trout are commonly reported, and yet are poorly characterised. We therefore undertook a comprehensive study of diplomonads from German rainbow trout Oncorhynchus mykiss, using scanning and transmission electron microscopy, and sequencing of the small subunit (ssu) rRNA gene. The diplomonad was identified as Spironucleus salmonis, formerly reported from Germany as Hexamita salmonis. Our new surface morphology studies showed that the cell surface was unadorned and a caudal projection was present. Transmission electron microscopy facilitated new observations of functional morphology, including vacuoles discharging from the body surface, and multi-lobed apices of the nuclei. We suggest the lobes form, via hydrostatic pressure on the nucleoplasm, in response to the beat of the anterior-medial flagella. The lobes serve to intertwine the nuclei, providing stability in the region of the cell exposed to internal mechanical stress. The ssu rRNA gene sequence clearly distinguished S. salmonis from S. barkhanus, S. salmonicida, and S. vortens from fish, and can be used for identification purposes. A 1405 bp sequence of the ssu rRNA gene from S. salmonis was obtained and included in a phylogenetic analysis of a selection of closely related diplomonads, showing that S. salmonis was recovered as sister taxon to S. vortens.

Laboratory transmission of the monogenean Acolpenteron ureteroecetes infecting the posterior kidneys of largemouth bass: time course and pathology.

Acolpenteron ureteroecetes infections in the kidneys of largemouth bass Micropterus salmoides have been reported, but the time course of infection and progression of pathology in experimentally infected fish remain unknown. We exposed 299 naive juvenile largemouth bass at 19.8 degrees C to A. ureteroecetes-infected largemouth bass via recirculating water without direct contact. For 7 months, prevalence and density were determined monthly in squashes of posterior kidney (20 exposed fish, 20 nonexposed fish), and histopathology was assessed in 5 fish from each group. Prevalence increased steadily from months 1 (5%) to 4 (85%), thereafter remaining relatively stable. Mean density of infection doubled monthly (month 1, 0.1 individuals/2 cm2 squash; month 7, 15.1 individuals/2 cm2 squash). Eggs were first observed at month 3, and mean density increased markedly from month 4 to month 5 (2.9-15.3 eggs/2 cm2 squash). Histopathology showed damage in renal collecting ducts that got progressively worse between 5 and 7 months. The infected ducts were dilated, had a hyperplastic epithelium, and were surrounded by chronic inflammation, including eosinophilic granular cells and varying degrees of fibrosis. Eggs within granulomas were present in the interstitium; this response is newly reported. The infection system developed in this study provides a reproducible and consistent source of infected individuals that will facilitate further study of the parasite and potential treatments.

Hepatic Calyptospora sp. (Apicomplexa) infection in a wild-born, aquarium-held clutch of juvenile arapaima Arapaima gigas (Osteoglossidae).

From Manaus, Brazil, 12 juvenile arapaima Arapaima gigas were imported to the United States and sent to 2 public aquaria, 1 private hobbyist, and 1 retailer. All 12 fish became ill within 4 to 6 wk of arrival, with signs of anorexia, lethargy, depigmentation, and ascites, and subsequently died despite antibiotic and anthelminthic therapy. Gross necropsies of 7 fish revealed serosanguinous coelomic effusion in all 7 fish, and branchial monogeneosis in 3 of 6 fish. The monogeneans from 1 fish were identified as Dawestrema cycloancistrium (Ancyrocephalinae). Histologic examination of 7 fish showed a variety of lesions, principally in the liver, gills, brain and gastro-intestinal tract. Numerous coccidian oocysts replaced 15 to 33% of the liver parenchyma in 6 of 7 fish examined. Light and transmission electron microscopy revealed that each oocyst contained 4 pyriform sporocysts bearing numerous sporopodia on their tapering, posterior end; approximately 25 to 30% of the length of the sporocyst was adorned. Each sporocyst was covered by a thin, membranous veil, contained 2 sporozoites, and stained brilliant pink with the Ziehl-Neelsen acid-fast method. This morphology is consistent with that of Calyptospora sp. (Lack of fresh material precluded determination to species.) This is the first report of Calyptospora sp. in arapaima. The Calyptospora sp. infection probably contributed to the morbidity and mortality of the captive arapaima.

Ultrastructure of Spironucleus salmonis n. comb. (formerly Octomitus salmonis sensu Moore 1922, Davis 1926, and Hexamita salmonis sensu Ferguson 1979), with a guide to spironucleus species.

Diplomonad flagellates can be associated with significant morbidity and mortality in fishes, particularly in farmed salmonids. Diagnosis using only light microscopy is limited, and species cannot be confirmed. We therefore undertook a comprehensive transmission electron microscopy study of 20 trophozoites from the intestine of farmed juvenile rainbow trout Oncorhynchus mykiss from Northern Ireland (reported as Hexamita salmonis by Ferguson in 1979). Re-assignment to the genus Spironucleus was determined based on the anteriorly tapering and intertwined elongate nuclei, anterior-medial kinetosomes, and the presence of a flagellar pocket. At the species level we observed a tri-radiate pattern of microtubules in the opening of the asymetrical striated lamina, comprising 3 to 5 microtubules following the edge of the flagellar pocket, 3 radiating away from the opening of the striated lamina, and 4 to 5 curving over the striated lamina. We observed electron-dense plaques adjacent to the kinetosomes, electron-dense bodies, numerous free ribosomes, aggregations of glycogen, bowl-shaped membranous structures, rough endoplasmic reticulum, and a novel distinctive pyriform sac of densely packed free ribosomes at the posterior of the cell (8-shaped in transverse section, and delineated by furrowed endoplasmic reticulum). We now propose to rename H. salmonis sensu Ferguson (1979) Spironucleus salmonis. Our review of the morphology of Octomitus salmonis illustrated by Moore (1922a,b) and Davis (1926), has shown that this organism also belongs to the genus Spironucleus. We synonymise H. salmonis sensu Ferguson (1979) with O. salmonis sensu Moore (1922) and Davis (1926), and rename them S. salmonis. An expanded diagnostic guide, including new cytoplasmic elements, is presented for the 4 species of Spironucleus from fishes (S. barkhanus, S. salmonis, S. torosa and S. vortens). We recommend that type descriptions of diplomonads be based on organisms taken directly from the host rather than from in vitro culture in order to reliably include the cytoplasmic organelles.

Cryptobia iubilans infection in juvenile discus.

Four commercial producers of discus (Symphysodon aequifasciatus) were found to have fish infested with the flagellate Cryptobia iubilans. Affected fish had granulomatous gastritis, and many also had granulomatous disease of other organs. The parasite had to be differentiated from the related flagellates Spironucleus spp, which induce different lesions. Transmission electron microscopy was found to be useful in detecting and identifying the parasite. Morbidity and mortality rates in the various fish populations appeared to be linked to a number of variables, including water quality, presence of other parasites and bacteria, diet, species, size, and age of the fish, and optimization of husbandry appeared to be important in alleviating the severity of disease. Metronidazole was not effective for treatment of C iubilans, but bath treatments with dimetridazole (80 mg/L for 24 hours, repeated daily for 3 days) or 2-amino-5-nitrothiazol (10 mg/L for 24 hours, repeated daily for 3 days) may be useful in decreasing the prevalence of infestation.

Hepatic calodium hepaticum (Nematoda) infection in a zoo colony of black-tailed prairie dogs (Cynomys ludovicianus).

Calodium hepaticum (syn. Capillaria hepatica), a nematode parasite commonly found in the liver of wild rodents, infects a wide variety of mammals, including humans. A retrospective study of black-tailed prairie dogs (Cynomys ludovicianus) at the Baltimore Zoo showed that 5 of 21 (24%) of the prairie dogs submitted for postmortem examination between 1981 and 2001 had hepatic capillariasis, with all the infections diagnosed during or after 1997. Affected livers contained multifocal granulomas containing numerous eggs and occasional adult nematodes. Asymptomatic wild rats in the zoo with a high prevalence of infection may have served as a reservoir for the disease. Wild rodent control is essential to minimize exposure of susceptible exhibition animals as well as humans to C. hepaticum.

Spironucleus vortens (Diplomonadida) in the Ide, Leuciscus idus (L.) (Cyprinidae): a warm water hexamitid flagellate found in northern Europe.

The hexamitid flagellate Spironucleus vortens, previously reported from Pterophyllum scalare from Florida, was found in the intestine of Leuciscus idus in Norway. The flagellate was cultivated and studied by scanning and transmission electron microscopy. Identification was based on a suite of ultrastructural features unique for S. vortens: compound lateral ridges, a swirled posterior end, and a distinctive microtubular cytoskeleton. Microfibrillar structures with a periodicity of 0.13 microm in the right peripheral part of the compound lateral ridges were shown to be responsible for the distinctive rope-like appearance of the peripheral ridge seen in scanning electron micrographs, and not previously reported for S. vortens. The present results show a wide geographic distribution and a wide temperature tolerance for S. vortens. The flagellate was successfully cultivated at 5 degrees C and 15 degrees C, having previously been cultivated between 2-34 degrees C. Spironucleus vortens is believed to be endemic in Norwegian waters, but an introduction hypothesis is also discussed. The similarity is striking between S. vortens and S. elegans, previously described from amphibians and fish in Europe, and the possibility of conspecificity is believed to be high.