Masking of Figure-Ground Texture and Single Targets by Surround Inhibition: A Computational Spiking Model

A visual stimulus can be made invisible, i.e. masked, by the presentation of a second stimulus. In the sensory cortex, neural responses to a masked stimulus are suppressed, yet how this suppression comes about is still debated. Inhibitory models explain masking by asserting that the mask exerts an inhibitory influence on the responses of a neuron evoked by the target. However, other models argue that the masking interferes with recurrent or reentrant processing. Using computer modeling, we show that surround inhibition evoked by ON and OFF responses to the mask suppresses the responses to a briefly presented stimulus in forward and backward masking paradigms. Our model results resemble several previously described psychophysical and neurophysiological findings in perceptual masking experiments and are in line with earlier theoretical descriptions of masking. We suggest that precise spatiotemporal influence of surround inhibition is relevant for visual detection

Basaloid squamous carcinoma of oral cavity: a histologic and immunohistochemical study

Basaloid squamous carcinoma (BSC) is an aggressive variant of squamous cell carcinoma (SCC) with a predilection for the upper aerodigestive tract. In the English literature, approximately 40 cases of BSC have been described in the oral cavity. BSC has frequently been confused with adenoid cystic carcinoma (ACC), basal cell adenocarcinoma, and undifferentiated SCC. The purpose of the investigation was to examine the histological features and immunohistochemical expression of differentiation-related substances, including cytokeratin (CK) subtypes, vimentin, S-100, chromogranin, laminin, and type IV collagen, for the characterization of biological features of these tumours. We studied three cases of BSC of the oral cavity, three cases of ACC, and one case of basal cell adenocarcinoma. Well-differentiated and undifferentiated SCCs were also studied for comparison. The BSCs showed many histopathologic similarities to cases previously reported. Among the CK subtypes analyzed, CK14 was the only subtype expressed by all basaloid cells of BSC. Potentially useful for the differential diagnosis was the finding of CKs 7 and 19 expression in the basaloid cells of ACC, and CKs 7 and 8 in basal cell adenocarcinoma. In BSCs, laminin and type IV collagen were found in the microcystic spaces between basaloid cells, but neither ACCs nor basal cell adenocarcinoma showed this feature. These data suggest that immunohistochemical findings are helpful in distinguishing BSC of the oral cavity from other histopathologically similar tumours. (C) 2002 Elsevier Science Ltd. All rights reserved.38772372

INCIDÊNCIA DE ALOIMUNIZAÇÃO ERITROCITÁRIA EM UM HOSPITAL ONCOLÓGICO DO MUNICÍPIO DE SÃO PAULO

Objetivos: Este estudo tem como objetivos determinar a prevalência de aloimunização e avaliar a frequência e a diversidade dos aloanticorpos antieritrocitários presentes em pacientes oncológicos predominantemente de órgãos sólidos atendidos no Hospital Municipal Vila Santa Catarina (HMVSC). Materiais e métodos: Este trabalho consiste em um estudo de análise retrospectiva que abrangeu todos os pacientes com Identificação de Anticorpo Irregular (IAI) positiva, excluindo anticorpos sem especificidade e autoanticorpos, atendidos pelo banco de sangue do HMVSC entre janeiro de 2023 e janeiro de 2024. Os pacientes foram classificados como politransfundidos se apresentassem um total de 6 ou mais transfusões em um período de 3 meses, de acordo com o protocolo do Hospital Israelita Albert Einstein (HIAE). Resultados: Foram verificados um total de 5.828 pacientes atendidos em nosso serviço de hemoterapia. Destes, 70 apresentaram algum anticorpo irregular, correspondendo a uma taxa 1,20% (70/5.828) de pacientes aloimunizados. Do total de pacientes aloimunizados, 14,30% (10/70) são politransfundidos e 22,85% (16/70) apresentaram múltiplas associações de anticorpos sendo a combinação de dois anticorpos a mais comum com 75% (12/16). Dentre os 70 pacientes aloimunizados encontramos 94 anticorpos irregulares com as seguintes frequências e especificidades; 26,60% (25/94) anti-E, 12,77% (12/94) anti-D, 11,70% (11/94) anti-K, 8,51% (8/94) anti-C, 7,45% (7/94) anti-Lea, 5,32% (5/94) anti-Dia, 5,32% (5/94) anti-c, 5,32%(5/94) anti-M, 2,13%(2/94) anti-G, 2,13% (2/94) anti-S, 2,13%(2/94) anti-Jkb, 2,13%(2/94) anti-Leb, 2,13%(2/94) anti-P1, 1,06%(1/94) anti-Jka, 1,06%(1/94) anti-Lua, 1,06%(1/94) anti-s, 1,06%(1/94) anti-I, 1,06%(1/94) anti-V e 1,06%(1/94) anti-Fya. Discussão: Na literatura, encontramos uma variedade de estudos sobre as taxas de aloimunização, que geralmente variam de 1% a 3% na população geral e de 1% a 10% em pacientes com câncer sólido não hematopoiético. O nosso estudo apresentou uma taxa próxima do limite inferior descrito pela literatura, o que acreditamos ser resultado de práticas adotadas em nosso serviço de hemoterapia, tais como: compatibilidade na fenotipagem Rh e Kell para pacientes com histórico de anticorpos irregulares e a leucorredução em todas as unidades de concentrado de hemácias e concentrado de plaquetas. Além das práticas adotadas, existem fatores intrínsecos ao paciente que podem influenciar a aloimunização, como: idade, etnia, estado imunológico (supressão ou inflamação) e resposta imunológica a antígenos não próprios. Atualmente, sabe-se que os pacientes podem ser classificados como “respondedores”ou “não respondedores”, e diversos estudos estão em andamento para identificar uma “assinatura”nos pacientes respondedores. Uma vez descoberta essa “assinatura”, será possível adotar estratégias mais eficazes na prevenção da formação de anticorpos irregulares. A maior frequência e incidência dos anticorpos irregulares, como anti-E, anti-D e anti-K, confirmam que os sistemas Rh e Kell continuam a ser os mais imunogênicos, depois do sistema ABO, na prática transfusional. Conclusão: Com este estudo conseguimos analisar o comportamento da taxa de aloimunização eritrocitária e a prevalência dos anticorpos irregulares dos pacientes atendidos no HMVSC, os resultados evidenciam que estamos adotando os procedimentos adequados para garantir uma terapia transfusional segura e eficaz

Serious adverse events associated with yellow fever 17DD vaccine in Brazil: a report of two cases

Background The yellow fever vaccine is regarded as one of the safest attenuated virus vaccines. with few side-effects or adverse events. We report the occurrence of two fatal cases of haemorrhagic fever associated with yellow fever 17DD substrain vaccine in Brazil. Methods We obtained epidemiological, serological, virological, pathological, immunocytochemical, and molecular biological data on the two cases to determine the cause of the illnesses. Findings The first case, in a 5-year-old white girl, was characterised by sudden onset of fever accompanied by headache. malaise, and vomiting 3 days after receiving yellow fever and measles-mumps-rubella vaccines. Afterwards she decompensated with icterus and haemorrhagic signs and died after a 5-day illness. The second patient-a 22-year-old black woman-developed a sore throat and fever accompanied by headache, myalgia, nausea, and vomiting 4 days after yellow fever vaccination. She then developed icterus, renal failure, and haemorrhagic diathesis, and died after 6 days of illness. Yellow fever virus was recovered in suckling mice and C6/36 cells from blood in both cases, as well as from fragments of liver, spleen, skin, and heart from the first case and from these and other viscera fragments in case 2. RNA of yellow fever virus was identical to that previously described for 17D genomic sequences. IgM ELISA tests for yellow fever virus were negative in case 1 and positive in case 2; similar tests for dengue, hantaviruses, arenaviruses, Leptospira, and hepatitis viruses A-D were negative. Tissue injuries from both patients were typical of wild-type yellow fever. Interpretation These serious and hitherto unknown complications of yellow fever vaccination are extremely rare. but the safety of yellow fever 17DD vaccine needs to be reviewed. Host factors, probably idiosyncratic reactions, might have had a substantial contributed to the unexpected outcome.3589276919