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Biomedical subjects

K O'Connor

Publications and source records attributed to K O'Connor.

At least 91 records · Page 5Linked to original sources
PubMed1983

An experimental analysis of fearlessness and courage.

In an attempt to assess the performance under stress of people who had received awards for gallantry, the subjective, behavioural and psychophysiological reactions of a group of seven decorated bomb-disposal operators were measured during a conflict test. Compared to a group of seven equally experienced and successful, but non-decorated, bomb-disposal operators, the decorated subjects maintained a lower cardiac rate when making difficult discriminations under threat of shock. There were no differences between the groups on subjective reactivity or on their performance under stress. Both groups of bomb-disposal operators reported having experienced fewer fearful reactions than did a small number of comparison subjects. The implications of the results for theories of fear and of courage are considered.

Adult↗
PubMed1980

Measles-specific lymphocyte reactivity and serum antibody in subjects with different measles histories.

Measles hemagglutination-inhibiting (HAI) antibody titers and measles-specific lymphocyte reactivity were studied in subjects who had previously received killed measles vaccine and had been recently reimmunized with live vaccine--persons who previously had atypical measles, subjects with multiple immunizations with live vaccine, adults with a history of measles, and persons with primary measles immunization. Twelve to 18 months after revaccination of former recipients of killed vaccine, all 31 subjects had measles HAI antibody titers greater than or equal to 10 and only three had lymphocyte stimulation indices (LSI) greater than 2.8. The mean LSI and geometric mean titer of antibody were similar to those of persons who had had natural measles many years ago. One subject who previously had atypical measles had an HAI titer of less than 5 and an LSI of 0.5; another had an LSI of 6.0 and an HAI titer of 80. Only one of seven subjects who were immunized more than once with live vaccine had an LSI of greater than 2.8 one year later. The finding of measles-specific lymphocyte reactivity and antibody levels in revaccinated former recipients of killed vaccine that are similar to those in persons who had natural measles suggests that the risk of future atypical measles in this group is slight.

Adolescent↗
PubMed1980

Electrocortical positivity and personality.

Individual differences in slow positive wave (SPW) amplitude occurring 200 to 400 msec. post-stimulus are reported in a group of 6 extraverts and 6 introverts. Introverts showed larger positivity of amplitude. Differences indicated that cortical specificity of components might relate to personality-specific attentional strategies.

Adult↗
PubMed1977

An intensive support unit for parent-infant distress.

Integration of the young infant with his parent(s), in the days and weeks after birth, should be as stress free as possible. In many families considerable distress is experienced in the parent-infant relationship. There is increasing evidence that distress of significant degree may have complex sequelae, particularly for the infant, and may affect growth and development in many areas. Child abuse is another expression of this distress. A unit aimed at providing intensive support for such distressed situations is described and evaluated on a short-term basis. The evaluation suggests that this unit is successful in alleviating many of the outcomes of such situations.

Attitude to Health↗
PubMed1976

Serological and genetic examination of some nontypical Streptococcus mutans strains.

Thirty-four strains of Streptococcus mutans whose antigenic or genetic positions were unclear or unknown with respect to the serological scheme of Bratthall (1970) and Perch et al. (1974), or the genetic (deoxyribonucleic acid base sequence homology) scheme of Coykendall were analyzed to clarify their relationship to previously well-characterized strains. Strain OMZ175 of the "new" serotype f was genetically homologous with strains of S. mutans subsp. mutans. Strains of the "new" serotype g were homologous with serotype d strains (S. mutans subsp. sobrinus). Strains isolated from wild rats constituted a new genetic group but carried the c antigen. Thus, strains within a "genospecies" (subspecies) of S. mutans may not always carry a unique or characteristic antigen. We suggest that the existence of multiple serotypes within subspecies represents antigenic variation and adaptations to hosts.

Animals↗
PubMedDate not supplied

Current status of small bowel radiography.

BACKGROUND: In the past, small bowel examinations were usually ordered for the sake of "completeness." As a result, small bowel radiography was performed casually and without attention to detail. This review examines pertinent clinical issues and the recent contribution of small bowel radiography to the evaluation and management of the patient with suspected small bowel disease. Recommendations for the clinical utilization of small bowel radiography are discussed. METHODS: Analysis of pertinent citations addressing valid indications for, and technique of, small bowel radiography from 1980 to July 1995 through a computerized bibliographic search (Medline and Current Contents). RESULTS: Accepted clinical indications for small bowel radiography include (1) unexplained gastrointestinal bleeding, (2) possible small bowel tumor, (3) small bowel obstruction, (4) Crohn disease, and (5) malabsorption. The current literature reflects the limitations of the conventional small bowel follow-through, various modifications to improve its clinical yield, the important contribution of enteroclysis in the workup, and subsequent management of patients with possible small bowel disease. A controversy in the radiology literature exists as to whether to use the small bowel follow-through or enteroclysis as the primary method of examining the small bowel. CONCLUSION: The thoughtful selection of patients by clinicians for small bowel radiography is essential to make radiologic evaluation cost effective. The incidence of disease of the small intestine is low and is associated with nonspecific symptoms. Because of the inherent difficulty of visualizing numerous loops of an actively peristalsing bowel, a reliable imaging method is needed that not only detects small or early structural abnormality but also accurately documents normalcy. The yield of information provided by enteroclysis and its high negative predictive value suggests that it should be the primary method for small bowel examination. The "overhead"-based conventional small bowel follow-through should be abandoned. The "fluoroscopy"-based small bowel follow-through augmented when necessary by the peroral pneumocolon or the gas-enhanced double-contrast follow-through method is an acceptable alternative when enteroclysis is not possible.

Crohn Disease↗
PubMedDate not supplied

Preparation and motor potentials in chronic tic and Tourette syndromes.

Many studies have found that people with tic disorder show more difficulty when inhibiting an automated than a controlled response. Furthermore, although normal motor threshold and excitability are present, but reduced or impaired, motor inhibition seems manifest in patients with tic. In order to localize this inhibition impairment in tic disorder the present study examine two response-locked ERPs: the Bereitschaft (preparation BP) and the motor potentials (MP). The simple tic group showed faster BP latency and smaller amplitude than control and complex tic group and did not show a corresponding change in values with practice or with automated or controlled condition. The MP amplitudes revealed that whereas both controls and complex tic disorder showed a decrease in amplitude during control condition for both blocks, simple tic showed larger amplitude. Our ERP results are in agreement with RT results of a previous study. The explanation could lie with modulation in motor excitation inhibition circuits and seems worse in simple tics where the movements are more automatic and nonvoluntary.

Automatism↗
PubMedDate not supplied

Are psychosocial factors related to smoking in grade-6 students?

The associations of psychosocial characteristics with both gender and smoking behavior were explored in a sample of 1552 grade-six students from 107 schools in one Ontario, Canada, school district. Ever smokers were more likely to have spending money: a part-time job; to have missed school in previous 2 months; perceive themselves to be below average or average in school; to have a mother, a father, and a sibling who smoke; to have consumed low alcohol and alcoholic beverages; and agree with fewer positive statements concerning second-hand smoke and the addictive properties of smoking. Ever smokers had more close friends who tried smoking, spent more time with friends, scored higher on depression, rebelliousness, and social conformity scales, reported more life events in the past year, and had lower scores for social support. More boys than girls had ever smoked (18.9% vs. 14.7%). Gender differences were found for sociodemographic, attitudes, social bonding, and psychosocial factors.

Adolescent↗
PubMedDate not supplied

Psychological distress and adaptational problems associated with discontinuation of benzodiazepines.

This study compared subjects who had received standard tapered withdrawal of benzodiazepine (BZD) (group 1) with a group with comparable diagnosis still receiving BZD (group 2) and a control group of comparable diagnosis not yet receiving treatment (group 3). Sixty subjects aged 21-65 years with a diagnosis of nonpsychotic anxiety or insomnia were included. The assessment of psychological distress and quality of life was timed to coincide with the maximum immediate effect of BZD discontinuation, as calculated according to drug half-life. Subjects diagnosed with insomnia reported lower distress in all three groups. The pattern of distress experienced by group 1 was closer to group 3 than to group 2, indicating the potential importance of re-emergence of anxiety. High neuroticism, lower education level, and lower quality of life were associated with higher levels of distress during withdrawal.

Adaptation, Psychological↗
PubMedDate not supplied

Tri-dimensional prostate cell cultures in simulated microgravity and induced changes in lipid second messengers and signal transduction.

The high aspect rotating-wall vessel (HARV) was designed to cultivate cells in an environment that simulate microgravity. We studied previously the effects of HARV cultivation on DU-145 human prostate carcinoma cells. We determined that HARV cultivation produced a less aggressive, slower growing, less proliferative, more differentiated and less pliant cell than other cell cultivation methods. The result was a 3-dimensional (3D) growth model of prostate cancer which mimics in vivo tissue growth. This work examines the signal transduction-second messenger pathways existing temporarily in these HARV cells and correlates these features with the special properties in growth and 3D spheroid formation. We found an initial very active ceramide, a diacylglycerol increase together with increases in PI-PLC and PLA(2) a central defect in PLD (no phosphatic acid or phosphatidylethanol at any time during 15 days of HARV cultivation). There is a cross-talk between ceramide and PI3K pathways with activation of PI3K, after 6 days of HARV growth concomitant with down-regulation of ceramide. At this time, there is also an increase of cAMP (seen by increases in arachidonic acid). Taken together these results can explain the 3D organoid-like growth. We therefore developed a model for growth in HARV prostate cancer cells which involve temporal "switches" between second messengers, activation and cross-talk between multiplicity of signaling pathways and a central defect in PLD pathways. Essential to the late slow growth, and 3D organotypic formation are the apoptotic, anti-survival, anti-proliferation and differentiation pathways in the first days of HARV, with growth of "new" different types of prostate cancer cells which set-up for later "switch" in ceramide-PI3K to survival and proliferation.

Cell Culture Techniques↗
PubMedDate not supplied

Information management for managed care.

A key concern for medical groups is how to manage information in a dual environment of capitation and fee for service. Information systems that work for one may not work for the other. Finding a system that works for both is critical. Some of the data that would be beneficial to collect for starting managing capitation contracts include: age/sex ratios of the practice patient population, average number of visits per patient per year, average number of visits by ICD-9 code for total population, average procedures per patient per year, and analysis of paverage payment per visit/procedure for commercial and Medicare patients. Some of the major concerns addressed include operational issues, financial viability and automated billing systems.

Capitation Fee↗
PubMedDate not supplied

No silver bullets.

Explore the source record for details and available documents.

Decision Making, Organizational↗