Oxyuricassis ekstromi n. sp. (Oxyurida: Pharyngodonidae) from Lasiancistrus saetiger (Siluriform: Loricariidae) from the Eastern Amazon.

Oxyuricassis ekstromi n. sp. is the third species of the genus described from the intestine of Lasiancistrus saetiger Armbruster in Brazil. This species can be easily differentiated from its congeners by the presence of a tooth-like sclerotized piece that occupies half of the stoma and absence of spine projections on the tail of both males and females. Also, males of the new species lack caudal alae present in Oxyuricassis coronatus and Oxyuricassis hexaspinatus. Additionally, we observed a different number and pattern of the distribution of cloacal papilla; males of O. coronatus and O. hexaspinatus have 1 pair of pre-cloacal and 2 pairs of post-cloacal papillae; while the new species has 1 pre-cloacal and 3 post-cloacal pairs of papillae.

Fleas of the genus Neotyphloceras associated with rodents from Bolivia: new host and distributional records, description of a new species and remarks on the morphology of Neotyphloceras rosenbergi.

The flea genus Neotyphloceras Rothschild (Siphonaptera: Ctenophthalmidae) includes five species and two subspecies distributed from Venezuela to southern Chile and Argentina. Only Neotyphloceras crassispina hemisus Jordan has been registered in Bolivia. The present study examines species of Neotyphloceras collected in Bolivian localities in the Departments of La Paz, Cochabamba and Tarija, and describes the morphology of the modified abdominal segments in males and females of Neotyphloceras rosenbergi Rothschild on the basis of type material and specimens collected from Tarija. A new species, Neotyphloceras boliviensis n. sp., is described and new host associations are reported for N. rosenbergi, Neotyphloceras crassispina crassispina and N. crassispina hemisus. Neotyphloceras c. crassispina and N. rosenbergi are reported for the first time in Bolivia. The distribution of N. rosenbergi is extended 1600 km to the south. Given the potential medical and veterinary significance of fleas as disease vectors, and considering that in the Departments of La Paz and Tarija several human cases of plague have been reported, and species of flea have been identified as main vectors of these diseases, the new records of fleas in Bolivia reported herein may be useful for epidemiological studies on flea-borne diseases.

Nematodes Parasites of Teiid Lizards from the Brazilian Amazon Rainforest.

This study presents the helminth composition and parameters of infection by several species of nematodes in teiid lizards, Ameiva ameiva ameiva (Linnaeus, 1758), Cnemidophorus cryptus Cole and Dessauer, 1993, and Kentropyx calcarata Spix, 1825 from the Brazilian Amazonian Rainforest. The population of lizards studied were parasitized by 6 species of Phylum Nemata including: Spinicauda spinicauda (Olfers, 1919), Parapharyngodon alvarengai Freitas, 1957, Physaloptera sp. (adults), Physaloptera sp. (larvae), Piratuba digiticauda Lent and Freitas, 1941, and Anisakidae (larvae). The overall prevalence was 66.17% and the mean intensity of infection was 19.40 ± 25.48. The association between the body-length of lizards and the abundance and richness of parasitic nematodes was statistically significant only in Ameiva a. ameiva. A new host record is reported here with 1 specimen of the family Anasakidae in Ameiva a. ameiva. Both S. spinicauda and Physaloptera sp. represent new records from C. cryptus.

A description of Neoechinorhynchus (Neoechinorhynchus) veropesoi n. sp. (Acanthocephala: Neoechinorhynchidae) from the intestine of the silver croaker fish Plagioscion squamosissimus (Heckel, 1840) (Osteichthyes: Sciaenidae) off the east coast of Brazil.

Plagioscion squamosissimus (Heckel, 1840) (Osteichthyes: Sciaenidae) is considered piscivorous and is a generalist species endemic to the Amazon region. This fish is an important part of the natural ecosystems in which it occurs and provides basic functional components in the food web. The genus Neoechinorhynchus Stiles & Hassall, 1905 is distributed worldwide and parasitizes fish and turtles, but there are few reports of parasites of this genus in South America, due to the high diversity of fish that can be found in this region. A new species of thorny-headed worm (Acanthocephala: Neoechinorhynchidae) is described from P. squamosissimus from Guajará Bay, Belém, Pará, Brazil. In general, the unique characteristics of the hooks on the anterior end of the proboscis and the length-to-width ratio relationship separate this new species from other described species in the genus Neoechinorhynchus. Although the species in this genus are mostly found in North America, the dearth of species known from the neotropics may be due to the lack of studies in this region.

SU-E-T-131: Influence of Scanning Speed on Measurements of Field Flatness and Symmetry of Photon Beams.

PURPOSE: The purpose of this study was to investigate influence of different scanning speeds on measurements of photon beam flatness and symmetry. METHODS: Commissioning and quality assurance of linear accelerators require extensive beam measurements. To increase efficacy, we evaluated flatness, symmetry and penumbra of 6MV photon beam using the Varian-TrueBeamTM system. Scanning speeds were 0.3, 0.5, 0.75, 1, 1.5, and 2.5cm/s. Measurements were performed in water phantom (BluePhantom2 , IBA-Dosimetry) at depths of maximum dose, 5,10, and 20cm, for 10×10 cm field size. For each scanning speed and depth, measurements were repeated five times to give results sufficient statistical significance, in both crossline and inline directions. Beam flatness was calculated using variation over mean (80%), whereas symmetry was calculated using point difference quotient (IEC) algorithm. After filed scanning chamber (Wellhofer) was fully stopped, system was paused for stabilization time of 15s to avoid buildup of ripples. RESULTS: It was noticed for all measurements that minimum and maximum flatness and symmetry were recorded when scanning speeds were 0.3cm and 2.5cm, respectively. For depth of maximum dose, maximum flatness and symmetry were 0.82% and 100.58% (crossplane), and 0.94% and 100.96% (inplane). The average was 0.76% and 100.38% (SD 0.04 and 0.12) for crossplane; 0.89% and 100.87% (SD 0.04 and 0.06) for inplane measurements. As the scanning depth increased, flatness and symmetry increased, but SD for all measurements was within the same range (0.04-0.07 and 0.04-0.12). The maximum absolute difference for flatness and symmetry for maximum and minimum speed were 0.16% and 0.34%.However, for scanning speeds from 0.5-1cm/s, results were almost identical with maximum SD 0.03 for both flatness and symmetry. Use of different scanning speeds did not influence penumbra; SD was 0 for all measurements. CONCLUSIONS: This study reveals small influence of scanning speed within predefined range. Consequently, difference in measurements does not have clinical significance.

SU-E-T-166: Use of an in Vivo Dosimeter to Assess the Implications of Daily Prostate Rotations.

PURPOSE: It is well established that using image guidance for prostate motion allows reduction of margin, dose escalation, decreased toxicity and recently improved outcomes. However, current methods only account for translational motion, not rotational variations. The purpose of this study is to assess whether rotations in anatomy lead to significant changes in the delivered dose for prostate patients. METHODS: Under an IRB approved protocol, 11 consecutive patients underwent prostate IMRT using IGRT with implanted metal-oxide semiconductor field-effect transistors (MOSFETs); the Dose Verification System (DVS) manufactured by Sicel Technologies. Two dosimeters were implanted per patient. From conebeam CT (CBCT) registration, corrections were applied to all translational errors. For rotations larger than 3 degrees, patient were repositioned and realigned to attempt to correct the rotation. Both translational and rotational errors based on the CBCT were documented. The daily DVS readings were compared to CBCT rotations about each axis (pitch, roll and yaw) and the root-mean square (RMS) rotation. RESULTS: 372 CBCT images were acquired. The correlation between rotation and DVS measurement was analyzed using linear regression. The R2 value for pitch was 0.059 and 0.144 for each dosimeter, respectively. For roll, the R2 values were 0.049 and 0.001. For yaw, the values were <0.001. For the RMS rotation, R2 was 0.034 and 0.038. As it could confound results, the angular dependence of the dosimeters was measured during commissioning and found that it was approximately 0.5% for 5 degree rotations. CONCLUSIONS: We did not find any significant correlation between prostate rotation around any axis and discrepancy in DVS reading. These results show that rotations seen clinically do not have a substantial effect on the dose delivered to the prostate. Further studies will attempt to determine at what angle rotations begin to affect the dose distribution, if at all.

SU-E-I-13: Evaluation of CT Number with Changing Scan Parameters for Nucletron Simulix Evolution CBCT.

PURPOSE: To quantify the variation in CT number generated by the Simulix Evolution CBCT with changes in scan length and phantom thickness. METHODS: Three phantoms were used in this study: CIRS Model 610 AAPM CT Phantom, Gammex 467 Tissue Characterization Phantom, and Catphan 600 phantom. The AAPM Phantom was used to assess the variation of HU with phantom thickness. Scans were acquired with two field size settings (full- and half-beam) with and without a 3.5 cm thick ring. The Catphan and Gammex phantoms were used to assess the Simulix's capability of producing a consistent CT-to-ED conversion table with different scan lengths, ranging from 1 cm (very thin) to 20 cm (clinical use). The data were also compared to data acquired with our in-house CT Sim (GE HiLite LightSpeed 16 slice). RESULTS: The AAPM phantom scans with and without the ring yielded an average difference in HU of 145 HU (full-beam) and 74 HU (half-beam) for each of five inserts. The HU for Cortical Bone (SB3) [largest Gammex electron density insert; 1.69] ranged from 923 to 1170 HU for the 4 cm and 1 cm scan lengths, respectively. The HU for Teflon [largest Catphan electron density insert; 1.867] ranged from 657 to 951 for the 20 cm and 1 cm scan lengths, respectively. The HU for air in Catphan ranged from -749 to -905, and the HU for LDPE [electron density 0.944] ranged from -82 to -42, for the 20 cm and 1 cm scan lengths, respectively. CONCLUSIONS: Results show a large variability in the calculated CT number with differences in phantom thickness, as evidenced by the results with the AAPM phantom. In addition, there appears to be a dependence on scan length, attributed to increased scatter contribution. Further tests will be done to evaluate the appropriateness of the use of the Simulix CBCT unit for heterogeneity corrected external beam treatment planning. The author has received no funding during the course of this research.

Polychlorinated biphenyls and biotransformation enzymes in three species of sea turtles from the Baja California peninsula of Mexico.

Concentrations of polychlorinated biphenyls (PCBs) as well as the expression patterns of cytochrome P450 (CYP) enzymes and glutathione-S-transferase (GST) activities were measured in livers of loggerhead (Caretta caretta), green (Chelonia mydas), and olive ridley (Lepidocheyls olivacea) sea turtles from the Baja California peninsula of Mexico. The mean concentrations of total PCBs were 18.1, 10.5, and 15.2 ng/g wet weight (ww) respectively for the three species and PCB 153 was the dominant congener in all samples. Total PCB concentrations were dominated by penta- and hexa-chlorinated biphenyls. The mean estimated TEQs were 42.8, 22.9, and 10.4 pg/g (ww) for loggerhead, green, and olive ridley, respectively, and more than 70% was accounted for by non-ortho PCBs. Western blots revealed the presence of hepatic microsomal proteins that cross-reacted with anti-CYP2K1 and anti-CYP3A27 antibodies but not with anti-CYP1A antibody. There were no significant differences in GST activities between species. Grouping congeners based on structure-activity relationships for CYP isoenzymes suggested limited activity of CYP1A contribution to PCB biotransformation in sea turtles. These results suggest potential accumulation of PCBs that are CYP1A substrates and provide evidence for biotransformation capacity, which differs from known animal models, highlighting the need for further studies in reptiles, particularly those threatened with extinction.

Delayed development of a biloma in an infant following hepatic injury / Desarrollo retardado de un biloma en un infante luego de un daño hepático

A case report is presented of an infant who developed a biloma over three months after major hepatic injury and after almost complete healing. A brief literature review is given to highlight unusual features of this case.

Se presenta el caso de un infante que desarrolló un biloma en tres meses, tras sufrir un serio daño hepático y luego de una curación casi completa. Se ofrece una breve revisión de la literatura a fin de destacar las características poco usuales de este caso.

Delayed development of a biloma in an infant following hepatic injury.

A case report is presented of an infant who developed a biloma over three months after major hepatic injury and after almost complete healing. A brief literature review is given to highlight unusual features of this case.

Learedius learedi infection in black turtles (Chelonia mydas agassizii), Baja California Sur, Mexico.

Black turtle (Chelonia mydas agassizii) carcasses, recovered as a result of incidental capture in Magdalena Bay, Mexico, revealed invasion by spirorchiid trematode eggs in liver, kidney, intestines, muscle, heart, pancreas, and duodenum. Seventy-five adult Learedius learedi Price, 1934, were recovered from the heart of 1 turtle. Most of the organs showed a mild or absent inflammatory response in histological sections, with the exception of a pancreatic-duodenal section that revealed severe lymphocyte and phagocyte infiltration associated with an infestation of more than 200 eggs. A linear formation of 35 eggs from the pancreas toward the intestinal lumen is described as resembling migration. This is among the first reports of a parasitic infection of L. learedi Price 1934, in C. m. agassizii in Mexico.

Vexillata liomyos n. sp. (Nemata: Ornithostrongylidae) from Liomys pictus (Rodentia: Heteromyidae) from Mexico, with comments on the synlophe of Vexillata armandae.

Individuals of a new species of Vexillata were collected from the small intestines of Liomys pictus from the Estaci6n de Biología Chamela, in Jalisco State, Mexico. The new species shows an array of characters that allow us to recognize it as a member of Vexillata; however, it can be distinguished from other species of the genus in that males possess an asymmetrical caudal bursa, females possess a characteristic cuticular inflation at the level of the ovijector, and both sexes possess a synlophe with 9 ridges at the midbody. Additional detail of the synlophe of Vexillata armandae Gardner et al., 1994 from Chaetodipus hispidus in New Mexico shows that both sexes have 12 cuticular ridges just posterior to the cephalic inflation, and in the posterior region of the body, females have 9 ridges of equal size while males possess 11 equal-sized ridges. In both sexes, the carene disappears at the posterior end of the body.

Helminthoxys abrocomae n. sp. (Nematoda: oxyurida) from Abrocoma cinerea in Bolivia.

A new pinworm parasite is described from Abrocoma cinerea, a caviomorph rodent of the superfamily Octodontoidea from the Andes of Bolivia. The new species, Helminthoxys abrocomae n. sp., possesses special secretory mamelons which we consider a synapomorphy of the genus Helminthoxys. Within Helminthoxys, the closest relatives are found in octodontoid rodents: H. gigantea occurs in Octodon degus in Chile and O. bridgesi in Argentina, and H. freitasi is a parasite of Thrichomys aperoides in Brazil. H. abrocomae n. sp. differs from both other species morphometrically in relation to different parts of the body in both sexes, particularly the size of the body, spicule, gubernaculum and eggs, by the presence of a rough cuticular area around the cephalic sensory papillae and by the possession of very well-developed cervical alae which are strongly curved dorsally. H. abrocomae n. sp. is the tenth nominal species described in Helminthoxys, all of them being parasites of caviomorph rodents.

Phylogenetic relationships among species of Stilestrongylus Freitas, Lent and Almeida, 1937 (Trichostrongyloidea: Heligmonellidae: Nippostrongylinae), parasites of myomorph rodents (Rodentia: Muridae) in the Neotropics.

The phylogenetic relationships of 14 species of Stilestrongylus were analyzed using the comparative morphology of 21 characters. We obtained 2 shortest trees of 50 steps, with a consistency index of 0.540 and 25 apomorphic character states. Ingroup monophyly was supported on these trees by 2 and 3 synapomorphies, respectively, and the ingroup was defined by the following characters: greater number of ventral ridges relative to the number of ridges dorsally, asymmetric bursa, and externodorsal rays differing in size. Sister-group relationships among Stilestrongylus and the other genera designated as outgroups are relatively consistent with those postulated by Durette-Desset's in a classification of the Nippostrongylinae. The ancestor of the species groups comprising Hassalstrongylus, Guerrerostrongylus, and Stilestrongylus originated and diversified in murids in the Neotropical region. Species of Hassalstrongylus occur in rodents between southeastern North America and the eastern part of South America (Brazil and Argentina), whereas species of Guerrerostrongylus and Stilestrongylus diversified exclusively in rodents in the Neotropics.

Three new species of Eimeria from Bolivian marsupials.

Faecal samples collected from 300 Bolivian marsupials (Didelphimorphia: Didelphidae) between 1984 and 1993 were examined for coccidian parasites. Sporulated oocysts were present in the faeces of 50 (17%) marsupials representing 11 genera and 22 species. Three new species of Eimeria are described and named from six host species. One species occurred in Marmosops dorothea, Monodelphis domestica and Thylamys venustus, another in Micoureus constantiae constantiae and Micoureus constantiae budini and a third in Marmosops dorothea. A discriminant analysis performed on five quantitative oocyst measurements revealed similarities between the first and third Eimeria species because of similar sizes and shapes of the oocysts, whereas the second Eimeria species was structurally discrete. The Eimeria that infects multiple hosts may be a common widespread species. Future surveys are advised for a thorough assessment of the coccidian biodiversity within Bolivian marsupials.

Lymphedema as a postulated cause of cutis verticis gyrata in Turner syndrome.

Unusual skin lesions were present at birth in four infants with Turner syndrome. The skin changes in these patients appear to have resulted either from in utero entrapment or pinching of edematous skin or from redundant skin remaining after in utero resolution of lymphedema. Distention by lymphedema is thought to cause several of the phenotypic characteristics seen in patients with Turner syndrome, including nuchal webbing and nail changes. In three of these patients the clinical appearance of the skin changes was similar to cutis verticis gyrata, marked by fixed thickened plaques in folds.

Two new species of Litomosoides (Nemata:Onchocercidae) from Ctenomys opimus (Rodentia:Ctenomyidae) on the altiplano of Bolivia.

Two filarioid nematodes, Litomosoides andersoni n. sp. and Litomosoides ctenomyos n. sp. (Nemata: Onchocercidae), are described from the mesenteries of the subterranean rodent Ctenomys opimus (Rodentia: Hystrichognathi) collected on the altiplano of Bolivia. Specimens collected near Rancho Huancaroma (Oruro Dept.) in 1984 and 1986 can be recognized as undescribed by the structures of the spicules and stoma and the shape of the ovijector. This record represents the first time members of the genus Litomosoides have been recovered from rodents of the family Ctenomyidae; this also represents the first published report of these nematodes from mammals in Bolivia.

A new species of Vexillata (Nemata: Ornithostrongylidae) from the coarse-haired pocket mouse Chaetodipus hispidus in New Mexico.

Individuals of a new species of trichostrongyloid nematode of the genus Vexillata were collected from the intestines of the coarse-haired pocket mouse Chaetodipus hispidus from eastern New Mexico. This new species possesses general features of the genus Vexillata but may be recognized as distinct from all other species by unique features of the dorsal ray of the caudal bursa and the synlophe.

A new species of Linstowia (Cestoda: Anoplocephalidae) from marsupials in Bolivia.

A new species of cestode of the genus Linstowia (Cestoda: Anoplocephalidae) is described from marsupials of the genera Thylamys and Monodelphis. The new species (Linstowia schmidti) differs from Linstowia iheringi Zschokke, 1904, in having a much smaller strobila and reduced number of proglottids, and in the distribution of the eggs in gravid proglottids. In Bolivia, cestodes of the genus Linstowia appear to have a restricted geographic distribution, occurring in marsupials only in southeastern Bolivia near the western margin of the Chaco. This host-parasite association may represent an ecological-historical relict.