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Biomedical subjects

J L Carroll

Publications and source records attributed to J L Carroll.

At least 73 records · Page 4Linked to original sources
PubMed1989

Hypoxia-induced periodic breathing in newborn lambs.

This study was designed to elucidate the effect of hypoxia on the breathing rhythmicity and the effect of hypoxia on periodic breathing (PB) in two groups of newborn lambs (less than 2 days and 10 days of age). Lambs undergoing a hypoxic ventilatory test [0.08 inspired O2 fraction (FIo2) for 13 min] experienced no apnea or PB in hypoxia, but all developed PB during the 1-min period immediately after their abrupt return to 0.21 FIo2. This PB occurred when alternation of arterial PO2 and PCO2 in mild hypoxic and hypocapnic conditions induced an overshoot-undershoot response of the chemical drive to breathe. The magnitude of PB was found to be greater in the animals with a higher peripheral chemoreflex sensitivity to hypoxia but ceased altogether when the hypoxic-hypocapnic conditions were resolved. When these conditions were removed more quickly, that is, when the animals were returned either to 0.50 FIo2 or to 0.03 FIco2, no PB was observed. To clarify the role of hypoxia as a central depressant on the genesis of PB, we tested to determine whether additional central tissue hypoxia, using carboxyhemoglobin (30%), would worsen the episodes of PB. No effect on breathing rhythmicity was observed. These findings suggest not only that, in newborn animals and adults, the mechanisms of post-hypoxia-induced PB are identical but that the PB elicited in mild hypoxic conditions is a peripheral chemoreflex-mediated event rather than a centrally mediated one.

Age Factors↗
PubMed1989

Visual-motor ability of children with articulation disorders.

The present study was done to assess differences between children with diagnosed functional articulation disorders and a control group on the variable of visual-motor ability. A group of 34 elementary children with articulation problems were matched with a control group of 34 for sex, age, and grade. Both groups were administered the Goldman-Fristoe Test of Articulation and the Minnesota Percepto-Diagnostic Test--Revised. Analysis indicated that children with articulation problems performed significantly lower on visual-motor skills.

Adolescent↗
PubMed1989

Comparisons of parents', teachers', and students' perceptions of self-concept in children from one- and two-parent families.

19 pairs of third grade children from intact and single-parent families matched for sex, intellectual ability, and academic achievement were administered a brief self-concept measure. Teachers and parents rated the students' self-concept on similar measures. There were no significant differences in scores between the groups; however, within each group the teachers and parents consistently overestimated students' self-esteem.

Child↗
PubMed1988

The relationship between the Millon Clinical Multiaxial Inventory and the MMPI in a private outpatient mental health clinic population.

The concurrent validity of the MCMI as compared to the MMPI was assessed by administering both tests to 106 newly admitted outpatients and calculating the intercorrelations between these two tests. Of the 20 MCMI scales, 12 were found to correlate with the MMPI in a manner that suggested that they do measure some degree of personality dysfunction, emotional disturbance, or specific psychological symptomatology. Eight of the MCMI scales failed to show correlations that would indicate that they effectively measure any of the pathological personality characteristics or clinically significant symptom patterns known to be measured by the MMPI.

Adolescent↗
PubMed1988

Peripheral chemoreceptor CO2 response during hyperoxia in the 14-day-old awake lamb.

We studied the interaction of O2 and CO2 at the peripheral chemoreceptors in 6 two-week-old awake lambs. The method used, which selectively tested the peripheral chemoreceptors, measured the immediate ventilatory (VE) response to pure O2 and then to O2 + CO2. From room air, the animal was switched abruptly to either pure O2 or O2 + 5% CO2, O2 + 7.5% CO2, or O2 + 10% CO2. VE was measured before and 8-10 sec after a step change in the inspired gas. In response to pure O2, VE/kg dropped 131 +/- 30 ml/min.kg (38%). Repeat O2 tests performed with the addition of CO2 showed that CO2 interacted to blunt the response to pure O2; the VE change from pre-test baseline to 8-10 sec being -77 +/- 42, -18 +/- 25, and +8.5 +/- 60 for 5%, 7.5%, and 10% added CO2 respectively. Carotid body denervation eliminated the immediate VE responses to O2 and CO2. We conclude that in the 2-week-old awake lamb, (1) hyperoxia suppresses the O2 drive output of the peripheral chemoreceptors, (2) during hyperoxia O2 and CO2 still interact at the chemoreceptor level, and (3) despite hyperoxia, the peripheral chemoreceptors retain a substantial graded response to incremental transient CO2 challenge.

Animals↗
PubMed1988

Response of newborn lambs to CO-induced hypoxia.

This study was undertaken to measure the neonate's response to CO-induced hypoxia in the first 10 days of life. CO breathing was used to induce hypoxia because CO causes tissue hypoxia with no or minimal chemoreceptor stimulation. An inspired gas mixture of 0.25 to 0.5% CO in air was used to raise the blood carboxyhemoglobin (HbCO) progressively from 0 to 60% over approximately 20 min. The study, conducted in awake conscious lambs aged 2 and 10 days, consisted in measuring the response of ventilation and the change in arterial blood gases during the rise of HbCO. The results showed that the 2- and 10-day-old lambs tolerated very high HbCO levels without an increase in minute ventilation (VE) and without metabolic acidosis. At both ages, HbCO caused no VE change until HbCO levels rose to between 45 and 50% after which the VE change was exponential in some animals but minimal in others. The VE change was brought about by a rise in tidal volume and respiratory frequency. During the period of maturation from 2 to 10 days, there was a small shift to the right in the VE-HbCO response. In the 10-day-old lambs the VE response to high HbCO was greater than that of the 2-day-olds because of the lambs' higher respiratory frequency response. Six of the 10-day-old lambs but only two of the 2-day-old lambs showed a hypoxic tachypnea to HbCO of 55-65%. None of the lambs developed periodic breathing, dysrhythmic breathing, or recurrent apneas with an HbCO level as high as 60%.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Decline in peripheral chemoreceptor excitatory stimulation during acute hypoxia in the lamb.

Chemoreceptor function was studied in eight 2- to 3-day-old unanesthetized lambs to sequentially assess hypoxic chemoreflex strength during an 18-min exposure to hypoxia [inspired O2 fraction (FIO2) = 0.08]. The immediate ventilatory (VE) drop in response to five breaths of pure O2 was measured at 3, 7, and 15 min during hypoxia. Each lamb was studied again at 10-11 days of age. At 2-3 days of age VE increased, with the onset of hypoxia, from 658 +/- 133 (SD) ml.min-1 X kg-1 to a peak of 1,124 +/- 177 ml.min-1 X kg-1. A dampening of the VE response then occurred, with a mean decline in VE of 319 ml.min-1 X kg-1 over the 18-min hypoxia period. Each pure O2 test (Dejours test) resulted in an abrupt fall in VE (delta VEDejours). This VE drop was 937 +/- 163, 868 +/- 244, and 707 +/- 120 ml.min-1 X kg-1 at 3, 7, and 15 min of hypoxia, respectively. Comparing the three O2 tests, delta VEDejours was significantly decreased by 15 min, indicating a loss of about one-fourth of the O2 chemoreflex drive during hypoxia. Testing at 10-11 days of age revealed a smaller VE decline during hypoxia. O2 tests at the beginning and end of the hypoxic period were not significantly different, indicating a smaller loss of hypoxic chemoreflex drive in the more mature animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1985

Differences between males and females in motives for engaging in sexual intercourse.

In a test of the hypothesis that a difference exists between males and females in motives for participating in sexual intercourse, a random sample of 249 college students was given a questionnaire containing questions about sexual behavior and attitudes, focusing on motives for having intercourse. There were significant differences between males and females in approval of casual sexual intercourse, number of premarital sexual partners, most important part of sexual behavior, and whether an emotional involvement was a prerequisite for participating in sexual intercourse. Effect-size analyses indicated that these differences are large, with a median omega 2 = 0.24. Both males and females approved of premarital sexual intercourse in a serious relationship and stressed the importance of feeling loved and needed. However, males found it easier to participate in sexual intercourse without an emotional commitment, whereas females were unlikely to want intercourse for physical pleasure in the absence of psychological involvement.

Adolescent↗
PubMed1985

Hypophosphatemia and Reye's syndrome.

Hypophosphatemia may occur in Reye's syndrome. We retrospectively studied 42 patients with Reye's syndrome to determine the frequency and degree of hypophosphatemia, to identify possible causes, and to determine whether hypophosphatemia was related to the severity of disease or mortality. Nineteen (46%) patients were hypophosphatemic at the time of hospital admission. Five of these had a serum phosphorus level less than 2.5 mg/dl and three were 1.5 mg/dl or less. During the subsequent hospital course, 32 (78%) patients developed hypophosphatemia. It was of moderate degree (2.5 mg/dl or less) in 20 patients, and was severe (1.5 mg/dl or less) in eight patients. Hypophosphatemia correlated with concurrent hyperglycemia but not with other potential causes studied. The degree of hypophosphatemia during treatment roughly paralleled the severity of illness but was not a predictor of outcome. The need for treatment of hypophosphatemia in Reye's syndrome has not been established, and hypocalcemia as a complication of excess phosphate infusion should be avoided.

Adolescent↗
PubMed1983

Early pneumococcal sepsis after pulmonary aspiration and the adult respiratory distress syndrome.

Bacterial pneumonia often complicates recovery several days after aspiration of gastric and oropharyngeal contents. Two children aspirated vomitus resulting in adult respiratory distress syndrome (ARDS) and suffered life-threatening pneumonia and septicemia caused by Streptococcus pneumoniae on the 2nd day after aspiration. We presume that inoculation of oropharyngeal bacteria into severely injured lung resulted in unusually rapid progression of infection. A high index of suspicion is necessary to detect this early complication because clinical signs of infection were obscured by ARDS.

Adolescent↗
PubMed1982

Performance of delinquent and nondelinquent high schools boys on the Rotter Incomplete Sentence Blank.

This study compared 30 delinquent adolescent boys who had been placed in a residential treatment center with 30 randomly selected high school boys on the Rotter Incomplete Sentence Blank (Rotter). For each group a maladjustment score was computed. The results indicated a significant difference between the two groups' mean maladjustment scores on the Rotter. A cut-off score was established that made it possible to correctly identify 73% of the normals and 60% of the residential treatment group. An item analysis was carried out between the two groups to see whether certain sentence stems discriminated between the two groups. Fourteen sentence stems were found to discriminate significantly between the groups. From these sentence stems a short form of the Rotter was established with a revised maladjustment score that correctly identified 82% of the boys in each group. A cross-validation of the short form with 48 high school boys and 67 delinquents supported its use as 75% of the high school boys and 80% of the delinquents were correctly identified.

Adolescent↗
PubMed1980

Acquisition, generalization, and maintenance of an assembly task by mentally retarded children.

Four TMR children were taught a three-piece assembly task. They were taught to verbalize the steps in the designated sequence before actually assembling the objects. Data were collected on their performance in both the training setting and in the regular classroom. Maintenance sessions were also recorded. Each child rapidly acquired the target behavior in the treatment setting and was successful in generalizing and maintaining the behavior in an extra-treatment setting.

Child↗
PubMed1979

Comparison of culturally deprived school achievers and underachievers on memory function and perception.

To compare the memory function and perception of culturally deprived achievers with underachievers, 36 culturally deprived children were assigned to one of two groups according to their achievement level, in relation to their age and IQ. Underachievers were children achieving 6 mo. or more below expected level. Achievers were children achieving within at least 5 mo. of expected level. All subjects were between the ages of 8 and 12 yr. and were in Grades 4, 5, or 6. Four tests were administered, the Block Design and Digit Span subtests of the WISC, Memory-for-Designs, and the Minnesota Percepto-Diagnostic Test. The two groups did not differ on the first three tests, but the achievers performed significantly better on the last test than the underachievers. It was speculated that the differences were related to level of motor execution.

Achievement↗
PubMed1977

Comparison of nonpsychiatric blacks and whites on the MMPI.

The literature indicates inconsistent results when MMPI differences between black Ss and white Ss were investigated. In general, most studies found that blacks responded in a more pathological direction. However, previous studies can be criticized because they have used students, prisoners, and hospital patients as Ss with variables that were controlled inconsistently and varied widely. In this study a comparison was made of MMPI scales for 56 black and 56 white males who were full-time employees of a large chemical company. Ss were matched for age, education, occupation, seniority, mental ability level, and socioeconomic level. The 10 standard clinical and 3 validity MMPI scales were recorded for each S as well as six experimental scales: Control (C), Dependency (DPD), Dominance (DOM), Ego Strength (ES), Anxiety Index (AI), and Internalization Ratio (IR). Using K corrected T-scores for the MMPI scales, a repeated measures analysis of variance indicated that subtests and group X subtests were significant. More specifically, blacks scored significantly higher than white Ss on the MA scale, and white Ss scored significantly higher than blacks on the PA, C, DOM, and Es scales. While the present study did find significant differences between black and white Ss on the MMPI, the scores were all well within the normal range (T less than 70), and all scales but two were less than 60.

Black or African American↗