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Biomedical subjects

C Neary

Publications and source records attributed to C Neary.

10 recordsLinked to original sources
PubMed2001

Antisense DNAs as multisite genomic modulators identified by DNA microarray.

Antisense oligodeoxynucleotides can selectively block disease-causing genes, and cancer genes have been chosen as potential targets for antisense drugs to treat cancer. However, nonspecific side effects have clouded the true antisense mechanism of action and hampered clinical development of antisense therapeutics. Using DNA microarrays, we have conducted a systematic characterization of gene expression in cells exposed to antisense, either exogenously or endogenously. Here, we show that in a sequence-specific manner, antisense targeted to protein kinase A RIalpha alters expression of the clusters of coordinately expressed genes at a specific stage of cell growth, differentiation, and activation. The genes that define the proliferation-transformation signature are down-regulated, whereas those that define the differentiation-reverse transformation signature are up-regulated in antisense-treated cancer cells and tumors, but not in host livers. In this differentiation signature, the genes showing the highest induction include genes for the G proteins Rap1 and Cdc42. The expression signature induced by the exogenously supplied antisense oligodeoxynucleotide overlaps strikingly with that induced by endogenous antisense gene overexpression. Defining antisense DNAs on the basis of their effects on global gene expression can lead to identification of clinically relevant antisense therapeutics and can identify which molecular and cellular events might be important in complex biological processes, such as cell growth and differentiation.

Adenocarcinoma↗
PubMed1993

Helmet slippage during visual tracking: the effect of voluntary head movements.

The influence of visual tracking on head movement and on the head/helmet system was investigated for two different helmets (a motorcycle helmet and a flying helmet) under static laboratory conditions. Subjects visually refixated between pairs of illuminated targets located at various horizontal (up to 160 degrees) and vertical (up to 90 degrees) distances apart while head position and helmet slippage were measured in azimuth, pitch, roll, X, Y, and Z using a double magnetic coil system. Results showed that for both helmets, root mean square (RMS) head movement increased with refixation distance, especially in the main axis of refixation, and that RMS helmet slippage can be a function of RMS head motion. Further, large individual differences in the degree of head motion were found. These findings may have implications for designers and investigators of helmet-mounted avionics.

Accommodation, Ocular↗
PubMed1991

Some visual, optometric and perceptual effects of coloured glasses.

We examined 20 individuals who had worn coloured glasses (Irlen filters) for a period of at least 3 months and who claimed to find them beneficial. Sixteen had a history of reading difficulties. The performance of a variety of visual tasks was compared: (1) using the coloured lenses; (2) using neutral density filters of similar photopic transmittance; and (3) using trial lenses to correct any residual refractive error. The coloured lenses appeared to reduce discomfort and susceptibility to anomalous perceptual effects upon viewing grating patterns. They also improved the speed of visual search by a small amount. The lenses had idiosyncratic effects on ocular muscle balance and acuity. They did not affect contrast sensitivity at a spatial frequency of 4 c/deg.

Adolescent↗
PubMed1989

Effects of phosphor persistence on perception and the control of eye movements.

When a rapid eye movement (saccade) is made across material displayed on cathode ray tube monitors with short-persistence phosphors, various perceptual phenomena occur. The phenomena do not occur when the monitor has a long-persistence phosphor. These phenomena were observed for certain spatial arrays, their possible physiological basis noted, and their effect on the control of eye movements examined. When the display consisted simply of two dots, and a saccade was made from one to the other, a transient ghost image was seen just beyond the destination target. When the display consisted of vertical lines, tilting and displacement of the lines occurred. The phenomena were more intrusive for the latter display and there was a significant increase in the number of corrective saccades. These results are interpreted in terms of the effects of fluctuating illumination (and hence phosphor persistence) on saccadic suppression.

Adult↗
PubMed1989

The effect of high frequency flicker on accommodation.

Monocular accommodation was measured by a laser optometer while two subjects viewed a letter matrix target illuminated by steady or intermittent (300, 100, 50 and 25 Hz) light and presented at a number of optical distances (0.5, 1.5, 2.5, 3.5 and 4.5 D). At certain rates of intermittent illumination, both above (50 Hz) and below (25 Hz) flicker fusion, an increased accommodation response was found. This increase occurred at all optical distances, except for the distance closest to each subject's dark focus, and resulted in a more accurate accommodation response for one subject, and a less accurate one for the other. Furthermore, for both subjects, evidence of an increase in the amplitude of the fluctuations in accommodation at 50 and 25 Hz was found for the higher stimulus levels. The implications of these findings for the control of accommodation and for practical problems of visual performance in the environment, such as visual discomfort associated with fluorescent lighting and intermittently illuminated visual display units, are discussed.

Accommodation, Ocular↗
PubMed1988

Distribution of IgE-bearing cells in renal biopsies in Wegener's granuloma.

A comparison was made between the renal biopsy appearances of Wegener's granuloma, microscopic polyarteritis and diffuse endocapillary proliferative glomerulonephritis, including the distribution of surface IgE-bearing mast cells. In microscopic polyarteritis and in other inflammatory conditions mast cells were usually associated with areas of interstitial inflammatory infiltrate, whereas in Wegener's granuloma mast cells were usually separate from areas of inflammation, suggesting a role for mast cells in the development of the renal lesion of Wegener's granulomatosis.

Adult↗
PubMed1982

Use of eye movement auditory biofeedback in the control of nystagmus.

Eye movement auditory biofeedback was used in weekly training sessions to control nystagmus in five adult patients. Within the 1st hr of training, all patients were able to reduce nystagmus. Average maximum group reduction of nystagmus amplitude, peak slow-phase velocity, and frequency achieved during training with auditory biofeedback was 82, 86, and 34%, respectively. At periodic intervals during training, audio information was withheld and patients were able to maintain reduced nystagmus for several minutes. In addition, patients were able to reduce nystagmus upon command without audio cues but with conscious effort while engaging in conversation and other tasks with the experimenters. Visual acuity improvement with conscious patient effort to control nystagmus but without auditory biofeedback averaged 10% Snell-Sterling. One of two patients who returned for post-training reevaluation was able to reduce his nystagmus quickly without auditory biofeedback to 50% of the pretraining level, and both patients were able with the aid of auditory cues to reduce their nystagmus rapidly to the level achieved during training. In addition to the improvement in vision, cosmetic and psychological benefits accrued. Eye movement auditory biofeedback should be considered in the treatment of nystagmus, either alone or in conjunction with orthoptic and/or surgical procedures.

Acoustic Stimulation↗