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Biomedical subjects

C O'Brien

Publications and source records attributed to C O'Brien.

86 records · Page 5Linked to original sources
PubMed1976

Cell-mediated destruction of human leukemic cells by MHC identical lymphocytes: requirement for a proliferative trigger in vitro.

These experiments have investigated cellular mechanisms involved in the generation of cellular immune responses to human acute leukemic blasts. Because normal human lymphocytes are not able to recognize immunologically, in vitro, lymphocytes from MHC identical siblings, the present studies have examined the in vitro proliferative and cytotoxic responses of normal lymphocytes to MHC identical AML and ALL blasts. In those cases where acute leukemic cells were unable to induce a proliferative response by MHC identical lymphocytes, the generation of effective anti-leukemic cytotoxicity required the addition of unrelated stimulating cells to the sensitization culture. In contrast, leukemic blasts that induced a proliferative response by MHC identical lymphocytes were also able to stimulate anti-leukemic cytotoxicity. This could be augmented by the addition of unrelated stimulating cells to the sensitization culture. The specificity of anti-leukemic cell cytotoxicity was demonstrated in all instances by simultaneous testing of putative killer cells on 51Cr leukemic blasts as well as 51Cr-labeled MHC identical phytohemagglutinin blasts or normal lymphocytes. Simultaneous sensitization to MHC identical leukemic blasts and unrelated stimulating lymphocytes did not invariably generate anti-leukemic cytotoxicity even when allogeneic cytotoxicity was observed; the absence of demonstrable suppressor activity in these nonreactive combinations suggested that some individuals may be specifically immunoincompetent, and thereby unable to generate effective anti-leukemic CML.

Cell Transformation, Neoplastic↗
PubMed1976

A system for rapid analysis of long-term recordings of heart rate and other physiological parameters.

Using miniature cassette tape recorders, measurement of ECG and other physiological measures is possible in industrial or working situations. The development of a semi-automatic high speed processing system for analysis of the tape recorded data is described. This system decodes the signals on the tape, converts ECG to heart rate and presents a listing of the heart rate variation over the recording period, which may be up to 24 hours. A punched paper tape copy of the listing is used for input into a mainframe computer for subsequent analysis. The recorders and processing system have been used extensively for three years on a study of industrial work stress, and have proved reliable, accurate, and of sufficient sensitivity for in-depth analysis. They allow considerable data to be collected, permitting the thorough statistical analysis necessary for the interpretation of complex physiological responses.

Computers↗
PubMed1975

Infants' home environments: a comparison of high-risk families and families from the general population.

Home environments of 30 infants at high-risk for developmental retardation were compared with those of 30 infants from the general population (matched for age, sex, and parity) by means of the Home Observation Measurement of the Environment. Fifteen high-risk infants attended a day-care intervention program; 15 did not. The Home Observation for Measurement of the Environment showed significant differences (ps less than .001) between the high-risk groups and the general population, favoring the general population, on all factors (maternal-warmth, absence of restriction and punishment, organization of the environment, appropriate toys, maternal involvement, and opportunities for variety) but none between the two high-risk groups.

Child Day Care Centers↗
PubMedDate not supplied

The phenotypic frequencies of group specific component and alpha-2-HS-glycoprotein in three ethnic groups. The use of these proteins as racial markers in forensic biology.

The phenotypic frequencies of group-specific component (Gc) and alpha-2-HS-glycoprotein (A2HS) were determined in White European, Asian and Afro-Caribbean populations. Typical allele frequencies were observed for Gc, with Gc 1S being the major allele for the first two groups and Gc 1F being the major allele for Afro-Caribbeans. For all groups the dominant A2HS allele was A2HS 1, although Asians had a significantly higher proportion of this allele than the White Europeans. Gc and A2HS either singly or in combination with other blood grouping systems provide good discriminating potential. The A2HS 10 allele was detected with a very low frequency in the White European group (A2HS 10 = 0.0013) and was not detected in the Asian group, while the Afro-Caribbean group had a relatively high frequency of this allele (A2HS 10 = 0.0966). The different distribution of the Gc 1F and A2HS 10 alleles in White Europeans and Asians compared with Afro-Caribbeans, can be used to determine the likelihood of blood coming from an Afro-Caribbean.

Africa, Western↗
PubMedDate not supplied

Lymphopenic effects on mice of a component of ammonia caramel, 2-acetyl-4(5)-tetrahydroxybutylimidazole (THI).

A derivative of ammonia caramel colour (AC) is known to induce a selective lymphopenia in rats. Accordingly, the haematological effects were studied in mice of oral administration in drinking water of 2-acetyl-4(5)-tetrahydroxybutylimidazole (THI), the component of AC responsible for lymphopenia. Initially five groups of BALB/c mice (five mice per group) were given doses of THI ranging from 0 to 200 parts/10(6) and bled weekly. Doses of THI from 5 to 100 parts/10(6) had no effect on circulating leucocytes over 6 weeks, but lymphopenia occurred with 200 parts/10(6). An increase in the concentration of THI to 400 parts/10(6) in the group on the lowest dose resulted in lymphopenia. An increase in dosage in two groups of mice, to 1000 and 2000 parts/10(6), resulted in marked lymphopenia. The number of neutrophils, eosinophils and monocytes remained unchanged throughout the experiment. Measurement of the proportions of CD4(L3T4)+ and CD8(Ly2)+ lymphocytes in lymph nodes from mice on high doses of THI did not show a selective depression of either subset, although both were increased relative to non-T cells. THI causes a selective lymphopenia in mice, as in rats, but at relatively higher doses, and merits investigation in mice as an experimental treatment for states of lymphocyte excess or overactivity.

Animals↗
PubMedDate not supplied

Finishing first grade: a study of school achievement in very-low-birth-weight children.

Factors that influence school achievement in very-low-birth-weight (< 1,500 g) children were investigated at the completion of first grade. The subjects were 71 children and their primary caregivers. Thirty-nine children were very low birth weight (VLBW) and 32 were normal birth weight (NBW). After controlling for birth weight status, over one third of the variance in children's school achievement was accounted for by the age of the child's mother when she began childbearing. Birth weight status accounted for significant amounts of variance in information processing skills. Significantly more children in the VLBW group required special services and fewer were promoted to second grade, although the difference was not significant.

Achievement↗
PubMedDate not supplied

Vulnerability and temperament in very low birth weight school-aged children.

The purpose of this study was to investigate parental perception of vulnerability, parental subjective stress concerning children's premature birth, and child temperament in families of very low birth weight (VLBW) and normal birth weight (NBW) children. The subjects were 39 VLBW children and 30 NBW 7-year-old children and their caregivers. Data on child temperament and parental perception of vulnerability was provided by the 69 families. Families of the VLBW group rated their degree of current stress concerning their children's premature birth. There were no differences between the NBW and VLBW caregivers in their perceptions of their child's vulnerability status. Caregivers of VLBW children had significantly lower scores on degree of subjective stress specific to the premature birth than the value reported on the standardization population. Child temperament made a significant contribution to parental perception of child vulnerability status in both VLBW and NBW parents.

Birth Weight↗
PubMedDate not supplied

Comparisons of rectal, femoral, axillary, and skin-to-mattress temperatures in stable neonates.

The purpose of this study was to compare four sites for temperature recording in the neonate: rectum, femoral, axilla, and skin-to-mattress. Simultaneous measurements were made at the four sites in 99 stable, term neonates. Temperatures were recorded each minute for 15 minutes. The optimal temperatures (highest temperature recorded minus 0.2 degrees F) did not vary across the four sites, but there were significant differences in the mean times required to achieve optimal temperature and in the optimal placement times (time required for 90% of the subjects to reach optimal temperature). The rectal site required significantly less time than the other sites (M = 2.66 minutes, optimal placement time = 5 minutes). The femoral and axillary sites required significantly more time than rectal and significantly less time than skin-to-mattress (M = 6 minutes, optimal placement time = 11 minutes). The skin-to-mattress site required significantly more time than the other sites (M = 8.5 minutes, optimal placement time = 13 minutes).

Axilla↗