Biomedical subjects

G L Burns

Publications and source records attributed to G L Burns.

At least 19 recordsLinked to original sources

PubMed2001

A confirmatory factor analysis on the DSM-IV ADHD and ODD symptoms: what is the best model for the organization of these symptoms?

Confirmatory factor analysis (CFA) was used to evaluate five different models for the organization of the DSM-IV ADHD and oppositional defiant disorder (ODD) symptoms (Model 1: a single factor model; Model 2: an ADHD and ODD two factor model; Model 3a: an inattention (INA), hyperactivity/impulsivity (HYP/IMP), and ODD three factor model; Model 3b: an INA, HYP/IMP, and ODD three factor model where the three IMP symptoms cross-load on the ODD factor; Model 4: an INA, HYP, IMP, and ODD four factor model). To evaluate these models, maternal ratings of ADHD and ODD symptoms were obtained at outpatient pediatric clinics on 742 children not in treatment and 91 children in treatment for ADHD. Model 3a resulted in a good fit as well as a significantly better fit than Model 2. Model 3a was also equivalent across treatment status, gender, and age groupings for the most part. Though Models 3b and 4 provided a statistically better fit than Model 3a, the improvement in fit was small and other model selection criteria argued against these more complex models.

Attention Deficit Disorder with Hyperactivity↗

PubMed2000

Factor structure of the Eyberg Child Behavior Inventory: a parent rating scale of Oppositional Defiant Behavior Toward Adults, Inattentive Behavior, and Conduct Problem Behavior.

Used the Eyberg Child Behavior Inventory (ECBI) to measure disruptive behavior problems in children and adolescents. A controversy exists, however, on the dimensional structure of the ECBI. To evaluate this issue, an exploratory factor analysis was first performed on a sample of 1,263 children and adolescents. This analysis identified 3 meaningful factors (i.e., Oppositional Defiant Behavior Toward Adults, Inattentive Behavior and Conduct Problem Behavior) and a fourth, poorly defined factor. A confirmatory factor analysis (CFA) evaluated the fit of the 3 meaningful factors in a second sample of 1,264 children and adolescents. The 3-factor model with 2 correlated errors provided a excellent fit. This 3-factor model also provided a significantly better fit than 2- and 1-factor models. Multiple group CFA indicated that the factor pattern, item-factor loadings, factor correlations, and correlated errors were equivalent across the samples. The CFA on sex yielded similar results. Initial normative information is presented for boys (n = 1,322) and girls (n = 1,205) within 4 age ranges (i.e., 2-5, 6-9, 10-13, 14-17) for the 3 factors. The use of these 3 factors, especially Oppositional Defiant Behavior and Conduct Problem Behavior, should make the ECBI more useful as a screening and outcome measure.

Adolescent↗

PubMed2000

Problem of item overlap between the psychopathy screening device and attention deficit hyperactivity disorder, oppositional defiant disorder, and conduct disorder rating scales.

Content validity requires a clear definition of the construct of interest and the delineation of the construct from similar constructs. Content validity also requires that the items be representative of the construct as well as specific to the construct. An examination of the items on the Psychopathy Screening Device (PSD), a parent- and teacher-rating scale of childhood psychopathy, indicates significant overlap with the symptoms and associated features of attention deficit hyperactivity disorder (ADHD), oppositional defiant disorder (ODD), and conduct disorder (CD). The failure of the PSD to have unique items results in poor discriminant validity with ADHD, ODD, and CD rating scales. More careful attention to content validation guidelines is required to develop a more useful measure of childhood psychopathy.

Antisocial Personality Disorder↗

PubMed1999

A ventricular assist device powered by conditioned skeletal muscle.

BACKGROUND: We are developing and testing a new ventricular assist device (VAD) to be powered by conditioned skeletal muscle. METHODS: To evaluate the VAD hardware and to develop a muscle training regimen, 8 calves have been used in studies in which the right latissimus dorsi muscle was employed. The experiments were carried out to an approximately 4-month duration. RESULTS: There was significant conversion of type II (fast twitch) to type I (slow twitch) muscle fibers. This did not correlate well, however, with device performance. The device stroke volumes ranged from approximately 17 to 90 cc. This variability of outcome occurred despite the fact that identical hardware, surgical procedures, and training regimens were employed. CONCLUSIONS: The results from the first eight studies lead us to speculate that perfusion may be important even when the muscle is working at pressures much lower than systemic blood pressure levels. In an attempt to augment tissue perfusion, we plan to investigate thermally induced angiogenesis as a possible mechanism for increasing blood flow to the tissue.

Animals↗

PubMed1998

Comparative effects of early weaning or once-daily suckling on occurrence of postpartum estrus in primiparous beef cows.

We concurrently evaluated early weaning and once-daily suckling as options for shortening postpartum interval to estrus in primiparous cows calving in good body condition. Over 2 consecutive years, a total of 77 primiparous cows were assigned to 1 of 3 treatments: control (ad libitum suckling); once-daily suckling (for 30 d prior to start of breeding); or early weaning (calves weaned 30 d prior to start of breeding). All cows had a body condition score (BCS) of > or = 5 at parturition and were maintained in good condition throughout the breeding season. Cows were observed for estrus twice daily and blood samples for subsequent measurement of progesterone were collected at 48-h intervals. For data analysis, cows were divided into early- (> or = 85 d post partum) and late-calving (< 85 d post partum) groups at the onset of the breeding season. All calves were weighed at birth, at the onset of treatment, at weekly intervals until the start of the breeding season, and within 45 d of 205 d of age. Early weaning or once-daily suckling shortened the postpartum interval to first estrus of late-calving primiparous cows by 17 (P < 0.01) and 12 d (P < 0.08), respectively, compared with control group cows. However, among early-calving cows, neither early weaning nor once-daily suckling influenced the postpartum interval. Postpartum intervals of once-daily suckled cows and early-weaned cows were similar (P > 0.10).

Animals↗

PubMed1998

A retrospective analysis of factors contributing to calf mortality and dystocia in beef cattle.

Records of 2191 calvings from the Clemson University Beef Physiology Unit between 1981 and 1993 were analyzed to determine factors affecting malpresentation, mortality and dystocia. Only 20 (0.91%) parturitions involved malpresentation: posterior presentation (n = 14), leg deviations (n = 3), head deviations (n = 2) and breech birth (n = 1). Dystocia affected calf mortality within 24 h of birth (P < 0.05), with mortality increasing as the severity of dystocia increased. There was an overall 4.5% death loss within 24 h of birth, with 4 and 7% mortality rates for calves from multiparous and primiparous dams, respectively (P < 0.05). Mortality was higher for bull vs heifer calves (P < 0.05). Ninety-four percent of calvings were unassisted, while 6% were assisted births. Dystocia was greater (P < 0.01) in primiparous (17%) than in multiparous dams (4%). In births involving dystocia, 28.1% required mild traction, 69.3% required heavy traction and 2.6% required Cesarean section. Birth weights associated with normal births and mild traction (36 and 36 kg) were lighter than those associated with heavy traction and Cesarean section (40 and 42 kg, respectively; P < 0.05). In conclusion, malpresentations were too few to be of significance, and dystocia influenced mortality within 24 h of birth. Calf birth weight and parity of dam explained most of the observed variations in dystocia.

Age Factors↗

PubMed1997

Internal validity of the disruptive behavior disorder symptoms: implications from parent ratings for a dimensional approach to symptom validity.

A dimensional approach was used to evaluate the internal validity of the DSM-III-R ADHD-inattention, ADHD-hyperactivity/impulsivity, oppositional defiant disorder (ODD), and conduct disorder (CD) symptoms (i.e., whether a symptom has a stronger correlation with its own dimension that the other three). Parents rated 4,019 children between the ages of 2 and 19 on these symptoms. The results showed that 5 of the 6 inattention symptoms, 3 of the 4 hyperactivity symptoms, 1 of the 4 impulsivity symptoms, 6 of the 9 oppositional defiant disorder symptoms, and 8 of the 11 CD symptoms had significant internal validity. Confirmatory factor analysis (CFA) found support for inattention, hyperactivity/impulsivity, oppositional defiant, and conduct disorder dimensions. Multiple-group CFA also found support for factor pattern and loading invariance across gender. The implications of these results as well as the merits of the dimensional approach to symptom validity are discussed in the context of the DSM-IV changes in ADHD, ODD, and CD.

Adolescent↗

PubMed1997

Internal validity of attention deficit hyperactivity disorder, oppositional defiant disorder, and overt conduct disorder symptoms in young children: implications from teacher ratings for a dimensional approach to symptom validity.

Uses a dimensional approach to evaluate the internal validity of the attention deficit hyperactivity disorder (ADHD) inattention (I) and hyperactivity/impulsivity (H/I), oppositional defiant disorder (ODD), and overt conduct disorder (CD) symptoms (i.e., whether a symptom has a stronger correlation with its own dimension than the other three dimensions). In Study 1, teachers rated 1,445 children on the DSM-III-R I, H/I, ODD, and overt CD symptoms. In Study 2, teachers rated 1,711 children on the DSM-IV I, H/I, ODD, and overt CD symptoms. All the I symptoms showed internal validity in both studies. In contrast, the H/I symptoms and the ODD symptoms, especially the H/I symptoms, showed weaker internal validity. All the overt CD symptoms showed internal validity except the DSM-IV bullies others symptom, with this symptom being more strongly related to the ODD dimension. Confirmatory factor analysis provided support for a 4-factor model consisting of I, H/I, ODD, and overt CD factors. Finally, the importance of internal validity for the construct validation of the disruptive behavior symptoms is discussed.

Adolescent↗

PubMed1996

Revision of the Padua Inventory of obsessive compulsive disorder symptoms: distinctions between worry, obsessions, and compulsions.

The Padua Inventory (PI), a self-report measure of obsessive and compulsive symptoms, is increasingly used in obsessive compulsive disorder (OCD) research. Freeston, Ladouceur, Rheaume, Letarte, Gagnon and Thibodeau (1994) [Behaviour Research and Therapy, 32, 29-36], however, recently showed that the PI measures worry in addition to obsessions. In an attempt to solve this measurement problem, this study used a content distinction between obsessions and worry to revise the PI. The revision was constructed to measure five content dimensions relevant to OCD i.e. (1) obsessional thoughts about harm to oneself or others; (2) obsessional impulses to harm oneself or others; (3) contamination obsessions and washing compulsions; (4) checking compulsions; and (5) dressing/grooming compulsions. A total of 5010 individuals participated in the study, 2970 individuals completing the PI and the Penn State Worry Questionnaire (PSWQ) and an additional 2040 individuals completing only the PI. The results provided support for the reliability and validity of the revision. In addition, the revision of the PI was more independent of worry, as measured by the PSWQ, than the original PI. Support was thus found for the validity of the content distinction between obsessions and worry. The importance of this content distinction is also discussed for the evaluation of other hypothesized distinctions between obsessions and worry.

Adult↗

PubMed1996

Stress, coping, and social support in hypothetically psychosis-prone subjects.

This paper examined stress processes in hypothetically psychosis-prone individuals. Subjects scoring high on Perceptual Aberration/Magical Ideation (Per-Mag subjects), Anhedonia, and low-scoring control subjects were compared for scores on Hassles and Uplifts, cognitive appraisal, coping strategies, emotions in two stressful situations, and on perceived social support. The groups differed in their experiences of minor life events and Secondary Appraisal but not in Primary Appraisal or emotions. There were notable differences in coping patterns and perceptions of social support. Per-Mag subjects contrasted with controls in using more coping by Escape-avoidance and Accepting responsibility, and reported less social support. Anhedonic subjects differed in their experience of minor life events and coped less through Positive reappraisal and Seeking social support. Per-Mag subjects are mainly distinguished by their coping processes. Anhedonic subjects are also sensitive to the incidence of minor life events. The results indicate that risk factors, stress, and coping interact in the absence of mental disorder.

Adaptation, Psychological↗

PubMed1995

The utilization of nonpatient samples in the study of obsessive compulsive disorder.

Obsessive compulsive disorder (OCD) is increasingly studied in nonpatients, primarily through the selection of individuals who score high on a self-report measure of OCD. The usefulness of this methodology for understanding OCD presupposes that some of the individuals in the high-scoring group meet diagnostic criteria for OCD, that the obsessive-compulsive behaviors in the high-scoring individuals are stable across time to a certain degree, and that the features associated with OCD in patients also are found in the high-scoring nonpatients. Two studies are reported which provide support for these three assumptions. Together the studies suggest that OCD can be productively examined by the selection of individuals who score high on a self-report measure of OCD. Cautions in the use of this methodology for the study of OCD are also noted.

Adult↗

PubMed1994

Effect of dietary lipid supplementation on progesterone concentration and reproductive performance in suckled beef cows.

Using whole cottonseed as a lipid source, silage-based diets that were isocaloric and isonitrogenous yet varied in lipid level were fed to multiparous cows. In Experiment 1, 48 cows (n = 12 per treatment) were allotted to 1 of 4 treatments where diets were formulated to supply 3.9, 4.3, 5.3 and 6.3% of total lipid. In Experiment 2, 66 cows (n = 22 per treatment) were allotted to 1 of 3 treatments where diets were formulated to supply 3.1, 5.5 and 8.3% of total lipid. Length of the first ovarian cycle, length of the first normal estrous cycle, postpartum intervals to onset of ovarian luteal activity and to first estrus were not affected by diet (P>0.10) in either experiment. Mean progesterone (P(4)) concentrations for first normal estrous cycles were not different (P>0.10) in either experiment. Anestrous periods were divided into 3 phases for analyses: Phase I) parturition to onset of ovarian luteal activity, Phase II) first ovarian luteal activity and Phase III) first normal estrous cycle. No differences were observed in P(4) concentrations during any phase of the postpartum period. In conclusion, isocaloric and isonitrogenous diets with increasing levels of lipid had no effect on reproductive performance in suckled beef in these experiments.

Journal Article↗

PubMed1993

Inhibition of estrus and corpora lutea function with Norgestomet.

Forty-five nonpregnant, nonlactating, Angus and Brangus cows were utilized to determine how long a Norgestomet ear implant would inhibit estrus when administered at various stages of an estrous cycle. All cows completed a nontreated estrous cycle to ensure normal cyclicity. At the second observed estrus (estrus = Day 1), cows were randomly allotted to be treated at metestrus (Day 3 or Day 4, n = 15); at diestrus (Day 9 or Day 10, n = 14); or at proestrus (Day 15 or Day 16, n = 16). All cows received a 2-ml intramuscular injection of 3 mg of Norgestomet accompanied by a 6-mg Norgestomet ear implant, which remained in situ for 21 days, or until individual cows were observed in estrus. Estrus was inhibited for a mean (+/- SEM) of 18.7 +/- 0.7, 19.9 +/- 0.8, and 17.0 +/- 0.8 days, respectively, when cows were treated at metestrus, diestrus, and proestrus (metestrus and diestrus vs proestrus; P < 0.05). Estrus was inhibited for an entire 21-day implantation period in 27, 50, and 38% of cows treated at metestrus, diestrus, and proestrus, respectively (P > 0.10). Norgestomet inhibited estrus in all cows for 11, 17, and 11 days after implantation when treatment was initiated at metestrus, diestrus, and proestrus, respectively (P > 0.10). These data indicate that a 6-mg Norgestomet ear implant effectively inhibits estrus in all cows for a maximum of 11 days, with some cows exhibiting estrus by Day 12 with the Norgestomet implant in situ.

Journal Article↗

PubMed1993

Alprostadil: an effective antiplatelet agent for calves.

Aspirin and other nonsteroidal, antiinflammatory drugs inhibit human platelets, but their effect as an antiplatelet agent on bovine platelets is not certain. Since calves are used for cardiovascular implant research, need exists for an effective antiplatelet agent for this animal model. After screening a number of potential antiplatelet drugs for calves, Alprostadil (prostaglandin E1) appeared to be the most promising. Alprostadil was administered (intravenous continuous drip) to 8 calves. The concentration of the drug administered was gradually increased until 50% inhibition of platelet aggregation was obtained. Platelet function, blood pressure, body temperature, and hematologic parameters were closely monitored. For in vitro evaluation, Alprostadil was added to human or bovine blood, and the platelet aggregation and cyclic adenosine monophosphate levels were measured. Alprostadil inhibited both bovine and human platelets, although bovine platelets were relatively more responsive to this drug. At an infusion rate of approximately 0.20 micrograms/kg/min in vivo, Alprostadil showed 50% inhibition of platelet aggregation with slightly decreased blood pressure (7 +/- 6 mm Hg) but no adverse effects. Complete reversal of in vivo platelet inhibition was noted within 24 h after cessation of drug administration. This short half-life and the lack of significant adverse effects make Alprostadil an attractive antiplatelet agent for calves with cardiovascular implants.

Alprostadil↗

PubMed1993

Attributional antecedents of alcohol use in American Indian and Euroamerican adolescents.

American Indian and Euroamerican adolescents were compared in regard to the events that they saw as responsible for their alcohol use. American Indian males believed that heredity played a more important role in their use of alcohol than Euroamerican males. American Indian males also believed that fate was a more important influence on their use of alcohol than American Indian females and Euroamerican females and that environmental events (e.g., problems at home) were a less important influence than the three other groups. Euroamerican females saw distressing events as more responsible for their alcohol use than the American Indian females and Euroamerican males. Euroamerican females also saw themselves as more responsible for their alcohol use than the American Indian females and males and Euroamerican males. The treatment implications of these attributional differences in reasons for alcohol use are discussed, especially in regard to American Indian adolescent males.

Adolescent↗

PubMed1993

Infections associated with implanted blood pumps.

A variety of prosthetic blood pumps are currently undergoing experimental development or are available for clinical use. The Jarvik-7 and Jarvik 7-70 (Symbion-7 and Symbion 7-70) total artificial hearts (TAH) have been used worldwide both experimentally and for clinical mechanical circulatory support. Of the 190 patients implanted with these devices, 133 went on to cardiac transplantation and 68 of the transplanted patients are alive. Complications associated with the use of the TAH have included postoperative hemorrhage, thrombosis with thromboembolism and infection. The incidence of infection in the patients implanted with the TAH has declined-significantly since initial clinical use and is now near 30%. Staphylococcus epidermidis and Pseudomonas aeruginosa are the most commonly pathogens isolated from these devices.

Animals↗

PubMed1992

Hypnosis for the treatment of burn pain.

The clinical utility of hypnosis for controlling pain during burn wound debridement was investigated. Thirty hospitalized burn patients and their nurses submitted visual analog scales (VAS) for pain during 2 consecutive daily wound debridements. On the 1st day, patients and nurses submitted baseline VAS ratings. Before the next day's would debridement, Ss received hypnosis, attention and information, or no treatment. Only hypnotized Ss reported significant pain reductions relative to pretreatment baseline. This result was corroborated by nurse VAS ratings. Findings indicate that hypnosis is a viable adjunct treatment for burn pain. Theoretical and practical implications and future research directions are discussed.

Adolescent↗

PubMed1992

Thrombus with infection in total artificial heart animals.

From January 1980 to December 1990, several types of total artificial hearts were implanted into 378 animals. In a retrospective study of these animals, 147 (39%) were found to have thrombus with infection (T&I). The criteria for diagnosis was thrombus formation in the artificial heart and a positive blood culture. The most common pathogen isolated from T&I animals was Pseudomonas species. Concurrent skin lesions and contamination from the pressure lines may be the primary sources of infection, but bacterial translocation from the intestine is another possible route. The main pathological findings at necropsies of artificial heart animals with T&I were associated with sepsis, congestive heart failure, infected thrombus, thromboembolism, and multiple organ infarctions. Most thrombi appeared to have originated from valve junctions and connectors. On the basis of these observations, a possible mechanism for pathogenesis of T&I has been proposed. The results suggest that design improvements and surface modifications to reduce thrombosis are important factors that should be carefully considered. Similarly, it is important to eliminate the route of entry of pathogenic microorganisms. These findings imply that bacterial interaction with thrombus, device related bacterial colonization, and host immunomodulation and gut barrier function following artificial heart implantation need further investigation.

Animals↗