Biomedical subjects

N C Russell

Publications and source records attributed to N C Russell.

6 recordsLinked to original sources

PubMed1992

Disruption of saccade production during oculomotor tracking in schizophrenia and the use of its changes across target velocity as a discriminator of the disorder.

A clear measure of eye movement disorder (EMD) that reliably separated schizophrenic individuals from others would both give insight into the brain control of the disorder and provide an aid in diagnosis. In the present study, a detailed analysis was carried out of the interactions between the pursuit and saccadic components of eye movements at different target velocities. The subjects comprised schizophrenic patients, unipolar depressed patients, and normal controls. The speed of the slow pursuit component did not differ among the groups, but schizophrenic subjects made more saccadic movements at low target velocities, though they started further away from the target at high target velocities. On the basis of these differences, a slope was computed of the linear function that related the number of saccadic eye movements to the velocity of a ramp visual target. Slope direction was negative for schizophrenic subjects but positive for unipolar depressive and normal subjects, and the correct classification rate for subjects was 84%.

Adolescent↗

PubMed1990

Medroxyprogesterone acetate, nocturnal penile tumescence, laboratory arousal, and sexual acting out in a male with schizophrenia.

This study reports the effects of the antilibidinal drug, medroxyprogesterone acetate (MPA) on nocturnal penile tumescence (NPT) during sleep, tumescence responses to provocative audiotapes during wakefulness in the laboratory, and sexual behaviors in the hospital environment, in a conduct-disordered sexually aggressive male, who had not responded to previous treatment. NPT, laboratory tumescence, and sexual behaviors in the hospital environment were all decreased. Testosterone levels declined by 73% within 2 weeks of starting the drug and prolactin levels increased by 300% across the treatment period. The effects on NPT and laboratory arousal were still partially in evidence 2 months after the drug had been stopped, although testosterone levels had returned to predrug levels. Some differences between the NPT and daytime test data are discussed in terms of the probable importance of testosterone to erotic fantasy. NPT may be a useful addition to present methods for examining the effects of drugs used to suppress socially unacceptable sexual behaviors.

Adult↗

PubMed1990

Schizophrenic performance on line bisection: no simple lateralization defects.

Many studies have assessed the possible lateralization deficits of schizophrenics, and the results usually suggest left hemisphere dysfunction. Nevertheless, they have been variable. This may have been due to cognitive demand of the different tasks, not to changes in brain lateralization itself. In order to circumvent this problem, the present study evaluates the performance of schizophrenics on a simple but lateralized task, line bisection. Subjects bisected a line using either visual or tactile information, with the left or right hand, when it was placed in their left or right hemispace or directly in front of them. Schizophrenic subjects were not more erroneous than normals (variable error), nor were they biased differently from normals in either direction with either modality of sensory input (constant error). There were only two significant effects of group on the tactile line bisection, one of position x length x group and one of position x hand x end x length x group, both on constant error (directional bias). The lack of main effects and presence of interactions on these basic tasks suggests that apparent lateralization differences found in schizophrenic subjects are due not to a simple defect of brain lateralization but may stem from task demands and attention allocation.

Attention↗

PubMed1989

Release of saccades in schizophrenics: inattention or inefficiency?

This paper attempts to distinguish between inattention and inefficiency as the cause of the eye movement problems of schizophrenic subjects. It focuses on their release of fast saccadic eye movements in four different situations: interrupting smooth tracking, as double-jumps in refixation, and as inadvertent departures from steady fixation or too-early prediction moves. If an attention deficit causes saccades during tracking, they should be reduced only for schizophrenic subjects in the dark, when there is no contrasting background. Instead the reduction was present for all groups. If double-jumps in saccadic refixations were caused by inattentional instability, they should increase in schizophrenic subjects when the target is a temporary flash of light. Instead, they were reduced in all groups to almost none, suggesting a perceptual processing cause for the excess double jumps. If a global attentional problem of schizophrenia caused saccade release, saccade number should be correlated across the four situations. Instead, there were significant correlations only between departures and predictions in paranoid schizophrenic subjects (r = 0.728) and between predictions and looking in nonparanoid schizophrenic subjects (r = -0.855). This lack of over-all correlations suggests that a common inattentional problem does not produce these eye movement deficiencies. Instead, the perceptual influence on tracking and looking suggests that processing inefficiency is responsible for at least part of the deficit.

Adolescent↗

PubMed1988

Factors affecting the prognosis of primary liver carcinoma.

Analysis of the clinical records of 163 patients with primary liver carcinoma was performed to identify factors affecting prognosis. The overall 3-year survival rate was 10%, and the median survival was 7.8 months. Survival was similar for patients with single or multiple tumor nodules. There was no significant association between nodule size of 3 cm or larger and survival. Patients who underwent resection had a longer survival. For patients without cirrhosis, location of the tumor in the left lobe regardless of whether it is resected appears to be a prognostic factor associated with prolonged survival. Female sex and the absence of cirrhosis were also associated with longer survival.

Age Factors↗

PubMed1985

Questionable relationship between cholecystectomy and colon cancer.

The relationship between prior cholecystectomy and right-sided colon cancer was evaluated in a case-control study. The study population comprised 267 women with right-sided colon cancer (cases) and 268 women with left-sided colon cancer (controls). All patients were white females, aged between 40 and 69 years, and registered at The University of Texas M.D. Anderson Hospital and Tumor Institute between 1970 and 1982. Thirty cases (11.2%) and 21 controls (7.8%) had documented prior cholecystectomy (odds ratio 1.49, 95% confidence limits 0.83, 2.67). The temporal relationship between cholecystectomy and colon cancer and the presence of diabetes were also evaluated. The authors conclude that there is no significant relationship between prior cholecystectomy and the development of right-sided colon cancer.

Adult↗