Poster Session: Quantifying Visual Snow Symptoms with a Matching Task

The primary symptom of Visual Snow Syndrome (VSS) is a veil of dots/static flickering across the entire visual field. VSS is a serious but poorly understood disorder (prevalence 1.4-3.3%). Symptoms of VSS can interfere with daily tasks like driving and reading. However, few studies have examined VSS, and quantitative measurements of symptoms are lacking. We developed a matching task in which participants with VSS adjusted parameters of simulated visual snow on a computer screen; participants modified the contrast, density, speed, and size of an array of dots to match their visual snow. Simulated snow was generated by random independent draws from a binary distribution controlled by the contrast parameter. Snow density was adjusted by setting a proportion of pixels equal to the background luminance. The speed setting determined the lifetime of each snow element, after which it was replaced. Dot size was adjusted by moving closer or further from the display and recording the viewing distance, as perceived snow elements were generally smaller than one pixel viewed from 0.5 m. Individuals with VSS said the simulated snow closely resembled their perceived snow, and parameter settings were consistent across trials. Simulated snow contrast settings were relatively low and dot size was relatively small. This task provides a quantitative assessment of visual snow percepts, which may facilitate assessment of treatments/therapies and testing of hypotheses about underlying mechanisms.

A multilevel, low literacy dual language intervention to promote colorectal cancer screening in community clinics in Florida: A randomized controlled trial

One of the largest disparities in cancer mortality in the United States occurs with colorectal cancer (CRC). The objectives of this multilevel two-arm intervention trial were to compare the efficacy of two interventions to promote CRC screening (CRCS) with fecal immunochemical test (FIT) and examine sociodemographic and psychosocial predictors of FIT screening. Individuals ages 50-75 (n = 326) who were not up-to-date with CRCS, could understand English or Spanish, and were at average CRC risk were recruited from two federally qualified health centers (FQHCs) in Florida. Prior to intervention, CRCS rates in the FQHCs were 27.1% and 32.9%, respectively. Study enrollment occurred April 2018-November 2019. System-level intervention components included leveraging electronic medical record (EMR) systems and delivering patient reminders. Participants were randomized to C-CARES (education+FIT) or C-CARES Plus (C-CARES+personalized coaching [for those not completing FIT within 90 days]). Primary outcome was completed FIT returned <1 year. Primary outcome analyses were performed using logistic regression. 225 participants completed FIT (69.0% [95% CI: 64.0-74.0%]), with no significant difference in FIT uptake by intervention arm (67.3% C-CARES Plus vs. 70.8% C-CARES; p = .49). FIT uptake was significantly higher among patients who received intervention materials in Spanish (77.2%) compared to those who received materials in English (63.2%, p < .01). The personalized coaching in the C-CARES Plus arm did not appear to provide added benefit beyond the C-CARES intervention. Multilevel approaches that include EMR prompts, reminders, FIT access, and provision of low-literacy, language-concordant education can support efforts to improved community clinics' CRCS rates. Future efforts should focus on repeat FIT screening. Trial registration: The trial was registered at ClinicalTrials.gov (NCT03906110).

Detection of Fusarium oxysporum f. sp. melonis Race 1 in Soil in Colima State, Mexico

During the winters of 2002 and 2003, a wilt occurred in melons cultivated on 1,500 ha in Colima State, Mexico. Yield losses reached 25% of final production, despite soil disinfestation with 60% methyl bromide and 40% chloropicrin. On the basis of the observation of plants with necrotic xylem, yellowing, and wilting of leaves, this disease was identified provisionally as Fusarium wilt. During February 2003, four soil samples from affected fields were plated onto a Fusarium-selective medium (1), which resulted in the detection of 2,260 ± 357, 179 ± 76, 668 ± 357, and 1,391 ± 256 CFU/g of F. oxysporum (3). Thirty-one randomly chosen isolates were used to inoculate differential cultivars of melon as described by Risser et al. (4). The cultivars were Amarillo Canario (susceptible to all races), Diana (resistant to races 0 and 2), Tango (resistant to races 0 and 1), and Vulcano (resistant to races 0, 1, and 2) (2). Ten plants of each cultivar, grown on sterilized vermiculite, were inoculated at the first true-leaf stage by drenching with 200 ml of a conidial suspension (1 × 10⁵ CFU/ml) of each isolate. Noninoculated plants of each cultivar served as controls. Plants were maintained in a growth chamber with a 16-h photoperiod (18 × 10³ lux) and temperatures at 23 to 25°C. Yellowing, wilt, and vascular discoloration symptoms developed on cvs. Amarillo Canario and Diana following inoculation with each of the 31 isolates, while noninoculated plants remained symptomless. F. oxysporum was consistently reisolated on potato dextrose agar from the affected plants. On the basis of the combination of affected cultivars, all isolates were identified as F. oxysporum f. sp. melonis race 1. To our knowledge, this is the first report of F. oxysporum f. sp. melonis race 1 in Colima State, Mexico. References: (1) H. Komada. Rev. Plant Prot. Res. 8:114, 1975. (2) J. Marín Rodríquez. Portagrano 2004. Vadmecum de Variedades Hortícolas. Agrobook, Spain. 2004. (3) P. E. Nelson et al. Fusarium Species: An Illustrated Manual for Identification. Pennsylvania State University Press, University Park, 1983. (4) G. Risser et al. Phytopathology 66:1105, 1976.

Mating system parameters in species of genus Prosopis (Leguminosae)

The section Algarobia of genus Prosopis involves important natural resources in arid and semiarid regions of the world. Their rationale use requires a better knowledge of their biology, genetics and mating system. There are contradictory information about their mating system. Some authors claim they are protogynous and obligate outcrosser. However, some evidence have been shown indicating that they might not be protogynous and that they might be somewhat self-fertile. The current paper analyses genetic structure and mating system parameters in populations of seven species of this section from South and North America based on isozyme data. In all species a significant homozygote excess was found in the offspring population but not in mother plant genotypes. Multilocus and mean single locus outcrossing rates (tm, ts) indicated that about 15% selfing can occur in the studied populations. The heterogeneity between pollen and ovule allele frequencies was low suggesting population structuration, in agreement with the estimates of correlation of tm within progeny (rt) and correlation of outcrossed paternity (rp). The difference of FIS estimates between offspring and mother plants suggest some selection favouring heterozygotes between seedling and adult stages.

[A case of Prune Belly Syndrome. Prenatal diagnosis]

Prune Belly Syndrome is a rare and complicated condition affecting the genitourinary organs and abdominal wall, it was named after the aspect of the abdomen after the bladder has been drained. In its fully developed form presents with the triad: megalocyst, abdominal muscle deficiency and cryptorchidism. We present a case of a patient with 22 weeks of gestation with ultrasonographic diagnosis of a large thoracoabdominal cyst. The delivery was by cesarean operation. We analyzed the literature.

A new host of Trypanosoma cruzi from Jujuy, Argentina: Octodontomys gliroides (Gervais & D'Orbigny, 1844) (Rodentia, Octodontidae)

To identify wild hosts of Trypanosoma cruzi, surveys were conducted in the subandean valleys of Jujuy Province, Argentina, between June 1986 and March 1987. Seventy two mammals from 13 different species were examined by xenodiagnosis. Fifty two of them were mostly rodents trapped at the localities of Maimará, León and Tilcara, and the remainder had been kept in captivity at the Estación Biológica Experimental, in Jujuy. Trypanosoma cruzi infection was detected only in 2 Octodontomys gliroides (2 pos./8 exam. 25%) from all 72 examined mammals. Isolates were called Octodontomys Argentina 1 and 2 (OA1 and OA2). Both infected animals were caught at the archaelogical ruin of Pucará, at Tilcara. Repeated searches for triatomines in the ruin itself and in neighbour houses rendered negative results. Groups of mice inoculated with either OA1 or OA2 isolates became infected between 7 (OA1) to 12 days (OA2) postinoculation PI. Parasitemia peaks were observed between day 12th-14th PI. Scarce amastigote nests were found in myocardium and skeletal muscle. Mortality was observed only for mice inoculated with OA1. Isoenzyme patterns of OA1 and OA2 were identical to one found in dogs and slightly different from that of human parasites in Argentina. Bones from Octodontomys sp., were recently found in a cave, dated 10200-8600 BC, in Pumamarca, near Tilcara, Jujuy. There are evidences that O. gliroides cohabited with man in ancient times and was associated to the domestic cycle of T. cruzi transmission, playing a role like that of domestic caves in Bolivia.

Sylvatic American trypanosomiasis in Argentina. Trypanosoma cruzi infection in mammals from the Chaco forest in Santiago del Estero

Trypanosoma cruzi infection in sylvatic mammals of the quebracho woods of the eastern part of Santiago del Estero province, Argentina, was studied from October 1984 to December 1987. 301 mammals of 20 different species were caught. T. cruzi, characterized biologically and biochemically, was isolated by xenodiagnosis from 23 of 72 (32%) Didelphis albiventris opposums, 2/36 (5.5%) Conepatus chinga skunks, and one ferret (Galictis cuja). 53 opossum refuges were located and triatomine bugs were found in 2 of them: one male Triatoma infestans, infected with T. cruzi, and 5 uninfected nymphs of T. sordida, had all fed on opossum blood. Electrophoretic zymogram patterns of the T. cruzi populations isolated from opossums and skunks were similar to isoenzyme profiles already described for populations isolated from infected humans in Argentina. The small number of triatomines found in the opossum refuges seems inadequate to account for the prevalence of T. cruzi infection recorded for these mammals, so other possible contaminative routes of infection should be investigated.

The skunk Conepatus chinga as new host of Trypanosoma cruzi in Argentina

We report the first systematic epidemiological research carried out in Argentina on the skunk Conepatus chinga. Forty-nine animals were captured in the settlements of Amamá, Trinidad, and nearby forested areas located in the Department of Moreno, Province of Santiago del Estero, between April 1985 and May 1989. Isolation of parasites was done through xenodiagnosis, and their identification as Trypanosoma cruzi was achieved by biological and biochemical criteria. The isolate was highly virulent and pathogenic in inoculated C3H mice. Prevalence was 4.1% (2 of 49). Two facts account for a possible domestic source of infection: both infected skunks were captured near Trinidad, in an area that had never been treated with insecticides, and electrophoretic isoenzyme patterns of the parasites isolated from the skunks were identical to those found in humans. Because extensive deforestation probably would increase the distribution area of C. chinga, further investigation should be performed to evaluate the epidemiological role of this wild mammal.

Cerebral revascularization to a main limb of the middle cerebral artery in the Sylvian fissure. An alternative approach to conventional anastomosis

Thirteen patients underwent an anastomosis of the superficial temporal artery (STA) or a saphenous vein graft to one of the secondary trunks of the middle cerebral artery (MCA). They included five patients with giant MCA trifurcation aneurysms, four patients in whom an earlier conventional STA-MCA anastomosis had become occluded, two patients who had stenosis of one of the secondary limbs of the MCA, and one patient who had a carotid-cavernous fistula. One patient had a saphenous vein graft from the common carotid artery to a secondary trunk of the MCA to bypass an occluded internal carotid artery and severely stenosed external carotid artery. The primary advantages of this procedure are that a large-caliber anastomosis to one of the secondary limbs of the MCA immediately restores flow into the MCA tree with a larger amount of vessel filling than with a standard cortical bypass, and large vessels can be used for the anastomosis. The disadvantages are that one of the secondary branches of the MCA must be occluded, the cerebral hemisphere around the Sylvian fissure must be retracted, a lumbar subarachnoid drain is needed, and the anastomosis must be performed deep within the Sylvian fissure. The procedure is a satisfactory alternative in cases in which a conventional STA-MCA anastomosis has either failed or would be less likely to succeed.