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Biomedical subjects

P J Dolan

Publications and source records attributed to P J Dolan.

4 recordsLinked to original sources
PubMed1991

Hepatitis C: prevention and treatment.

Widespread screening of donor blood for hepatitis B led to the recognition that most cases of post-transfusion hepatitis were due to an agent or agents, collectively known as non-A, non-B. Until recently, the causative agent for non-A, non-B hepatitis was unknown. In 1988, a new agent, hepatitis C virus, was identified. It is estimated that 150,000 new cases of hepatitis C occur each year and that one-half of patients with hepatitis C develop chronic liver disease. Hepatitis C is responsible for 15,000 new cases of cirrhosis annually. In 1990, an antibody assay was approved for commercial use. Widespread screening of donor blood with this assay should reduce the risk of transfusion-associated hepatitis C. For those patients already infected, antiviral therapy with alpha interferon may offer the chance of cure or significant palliation.

Blood Donors↗
PubMed1990

Effects of trauma to the mandibular nerve on human perioral directional sensitivity.

The capacity of 4 patients who had previously experienced trauma to their mandibular nerves to distinguish opposing directions of tactile motion over the distribution of the mental nerve was compared to that of 8 neurologically normal adults. Brushing stimuli were delivered to the perioral region and were precisely controlled for their velocity, the length of skin traversed, the width of skin contacted, and the orientation and direction of motion. A temporal, 2-alternative, forced choice method was used to obtain estimates of directional sensitivity, d'. It was discovered that impairment in cutaneous directional sensitivity could be readily detected within areas of hypaesthesia. Although directional sensitivity was found to increase linearly with the length of skin traversed for both the patients and the neurologically normal adults, the slope and the x-intercept of the linear relationship differed between the two groups. The difference in the slope suggests that direction discrimination within the hypaesthetic areas is relatively insensitive to changes in the length of skin traversed. The difference in the x-intercept suggests that a greater length of skin must be traversed before any information about direction is made available at the hypaesthetic sites. The dependency of the capacity of neurologically normal and impaired individuals to process information about direction of tactile motion on the length of skin traversed and the velocity of stimulation suggests that a high degree of stimulus control is required for the detection and quantification of subtle neurosensory deficits.

Adolescent↗
PubMed1989

Effects of traverse length on human perioral directional sensitivity.

The capacity of 8 neurologically healthy adults to distinguish direction of motion on the skin overlying the mental foramen was determined. The velocity, orientation, and the length and width of skin traversed by the moving tactile stimuli were precisely controlled. Directional sensitivity, d', was found to depend on both stimulus velocity and the length of skin traversed. Since the relationship between d' and velocity at each traverse length was well described by a generalized gamma function, it was possible to quantitatively characterize the effects of changes in traverse length on the relationship between d' and velocity. Specifically, peak (i.e., maximal) directional sensitivity increased as the length of skin traversed was increased, yet the velocity which resulted in peak directional sensitivity (i.e., the optimal or model velocity) remained invariant over the range of traverse lengths investigated (0.35-1.0 cm). The effect of stimulus velocity on directional sensitivity was least at the longest traverse lengths used. The generalized gamma function model fit the relationship between directional sensitivity and velocity equally well at all traverse lengths studied. The results lead us to anticipate that stimuli of the type used in this study should prove valuable for the detection and quantification of disturbances in orofacial tactile spatiotemporal integration in patients with peripheral nerve injury.

Adolescent↗