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Articles 121 - 123 of 123

Full-Text Articles in Ophthalmology

Transcranial Magnetic Stimulation Of The Prefrontal Cortex Delays Contralateral Endogenous Saccades, Tony Ro, Avishai Henik, Liana Machado, Robert D. Rafal Jul 1997

Transcranial Magnetic Stimulation Of The Prefrontal Cortex Delays Contralateral Endogenous Saccades, Tony Ro, Avishai Henik, Liana Machado, Robert D. Rafal

Publications and Research

The contributions of the superior prefrontal cortex (SPFC) and the superior parietal lobule (SPL) in generating voluntary endogenous and reflexive visually guided saccades were investigated using transcranial magnetic stimulation (TMS). Subjects made choice saccades to the left or right visual field in response to a central arrowhead (endogenous go signal) or a peripheral asterisk (exogenous go signal) that were presented along with a single TMS pulse at varying temporal intervals. TMS over the SPFC increased latencies for saccades made in response to an endogenous go signal toward the contralateral hemifield. No effects were observed when the go signal was exogenous …


Population Genetic-Study Among The Orang-Asli (Semai-Senoi) Of Malaysia - Malayan Aborigines, Mary Anne Tan Jin Ai Jan 1995

Population Genetic-Study Among The Orang-Asli (Semai-Senoi) Of Malaysia - Malayan Aborigines, Mary Anne Tan Jin Ai

Mary Anne Tan Jin Ai

A population genetic study was undertaken to provide gene frequency data on the additional blood genetic markers in the Semai and to estimate the genetic relations between the Semai and their neighboring and linguistically related populations by genetic distance and principal components analyses. Altogether 10 poly morphic and 7 monomorphic blood genetic markers (plasma proteins and red cell enzymes) were studied in a group of 349 Senoi Semai from 11. aboriginal settlements (villages) in the Pahang State of western Malaysia, Both the red cell glucosed-phosphate dehydrogenase (G6PD) and 6-phosphogluconate dehydrogenase (PGD) loci reveal the presence of polymorphic frequencies of a …


Modulation Of Mhc Expression On Human Endothelial-Cells By Sera From Patients With Systemic Lupus-Erythematosus, Mary Anne Tan Jin Ai Dec 1992

Modulation Of Mhc Expression On Human Endothelial-Cells By Sera From Patients With Systemic Lupus-Erythematosus, Mary Anne Tan Jin Ai

Mary Anne Tan Jin Ai

Major histocompatibility complex (MHC) antigen expression on cells is a prerequisite for immune interaction with activated T-cells. This study examined the ability of sera from patients with systemic lupus erythematosus (SLE) to modulate MHC expression on vascular endothelial cells. SLE sera were able to selectively upregulate MHC class I antigen expression on cultured human umbilical venous endothelial (HUVE) cells, without concomitant induction of MHC class II antigen. The stimulation index (SI) for MHC class I expression produced by SLE sera (1.21 ± 0.23) was significantly higher than those for normal controls (1.01 ± 0.10) (P < 0.0001) and non-SLE patients (1.12 ± 0.14) (P < 0.05). Additionally, active SLE patients had higher mean SI than inactive patients (P < 0.001). Preincubation of SLE sera with Protein A-Sepharose beads conjugated with antibodies against tumor necrosis factor-α and interferon-α was able to significantly reduce their ability to upregulate class I MHC expression by HUVE cells, indicating that these cytokines were responsible for the modulatory effect. This could be an important mechanism for the immune-mediated vascular injury seen in SLE.