Exposure-to-treatment interval and clinical severity in canine poisoning: a retrospective analysis at a Portland veterinary emergency center.
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Animals↗
Biomedical subjects
K S White
Publications and source records attributed to K S White.
Fatal paraquat poisoning in seven Portland, Oregon, dogs.
Paraquat is one of the few broad-spectrum herbicides available in the US; however, it is extremely toxic to companion animals when ingested. Despite its restricted use status, poisoning of dogs and cats remains relatively common. This clinical report documents a series of chronologically and geographically related cases of presumed malicious and fatal sub-acute paraquat poisoning in 7 dogs in Portland, OR. All animals developed acute gastrointestinal disturbance, renal compromise and insidiously progressive respiratory failure. Hyperlipasemia and moderate hypertension were notable featured in 5/7 cases. Trace levels of paraquat were demonstrated in the urine of 4/7 animals by gas-liquid chromatography/mass spectroscopy. Diagnosis in the remaining 3 cases was made through a combination of history or exposure, clinical signs and their progression, and pulmonary and renal histopathology.
Animals↗
Ferromagnetism of 3He films in the low-field limit.
We provide evidence for a finite-temperature ferromagnetic transition in two dimensions as H -->0 in thin films of 3He on graphite, a model system for the study of two-dimensional magnetism. We perform pulsed and cw NMR experiments at fields of 0.03-0.48 mT on 3He at areal densities of 20.5-24.2 atoms/nm(2). At these densities, the second layer of 3He has a strongly ferromagnetic tendency. With decreasing temperature, we find a rapid onset of magnetization that becomes independent of the applied field at temperatures in the vicinity of 1 mK. Both the dipolar field and the NMR linewidth grow rapidly as well, which is consistent with a large (order unity) polarization of the 3He spins.
Journal Article↗
Thoracic imaging of pediatric lymphomas.
Lymphoma (Hodgkin and non-Hodgkin types) is the most common intra-thoracic neoplasm in the pediatric age group. Diagnostic strategies and treatment approaches for these tumors are largely determined by protocols established by one of the large, multi-institutional cooperative groups. In this paper, Hodgkin and non-Hodgkin lymphoma is discussed in the context of these cooperative group protocols. The basic biology, patterns of primary and metastatic disease distribution, treatment approaches, imaging follow-up, and areas of active research are discussed.
Child↗
Evaluation of Responding in Peaceful and Positive Ways (RIPP): a school-based prevention program for reducing violence among urban adolescents.
Evaluated Responding in Peaceful and Positive Ways (RIPP)--a 6th-grade universal violence prevention program. Classes of 6th graders at 3 urban middle schools serving predominantly African American youth were randomized to intervention (N = 321) and control groups (N = 305). Intervention effects were found on a knowledge test but not on other mediating variables. RIPP participants had fewer disciplinary violations for violent offenses and in-school suspensions at posttest compared with the control group. The reduction in suspensions was maintained at 12-month follow-up for boys but not for girls. RIPP participants also reported more frequent use of peer mediation and reductions in fight-related injuries at posttest. Intervention effects on several measures approached significance at 6-month and 12-month follow-up. The program's impact on violent behavior was more evident among those with high pretest levels of problem behavior.
Adolescent↗
Structure of anxiety symptoms in urban children: competing factor models of the Revised Children's Manifest Anxiety Scale.
The Revised Children's Manifest Anxiety Scale (RCMAS; C. R. Reynolds & B. O. Richmond, 1985) is among the most widely used self-report measures of children's anxiety. The authors compared its current empirically derived factor structure with theory-driven models derived from 8 experts on child anxiety using concept mapping. Confirmatory factor analyses compared models using data from 898 seventh graders in an urban public school system serving a high percentage of African Americans. The most parsimonious best-fitting model was an expert-derived model with factors reflecting anxious arousal, social evaluation-oversensitivity, worry, and a higher order factor. This model was theoretically meaningful, excluded items less relevant to anxiety, and was invariant across gender. Future research with the RCMAS should consider use of these dimensions. The combination of qualitative and quantitative methodology used in this study appeared to have considerable utility for refining measures.
Adolescent↗
The structure of self-reported aggression, drug use, and delinquent behaviors during early adolescence.
Examined the structure of self-report scales designed to assess the frequency of adolescent problem behaviors. Urban (n = 988) and rural (n = 1,895) middle school students completed the Problem Behavior Frequency Scale (Farrell, Danish, & Howard, 1992a) and measures of other relevant constructs. Confirmatory factor analyses supported a model that included specific factors related to aggression, drug use, and delinquent behaviors, and a higher order problem behavior factor. Findings did not support a distinction between physical and nonphysical aggression. Results were generally consistent across settings (i.e., urban vs. rural) and gender. Other relevant constructs, including peer pressure for drug use and attitudes favoring aggression, had both specific associations with relevant first-order factors and more general associations with the second-order factor. These findings support the construction of separate scales assessing specific domains of problem behaviors in studies of adolescents' problem behaviors.
Adolescent↗
Peer influences and drug use among urban adolescents: family structure and parent-adolescent relationship as protective factors.
The moderating influences of family structure and parent-adolescent distress on the relationship between peer variables and drug use were examined in a predominantly African American sample of 630 10th graders at 9 urban high schools. Both peer pressure and peer drug use were significantly related to the reported frequency of drug use. The relationship between peer pressure and drug use was stronger among girls than boys, and also among adolescents in families without fathers or stepfathers. The association between peer pressure and drug use also increased as a function of the level of mother-adolescent distress among adolescents who were not living with fathers or stepfathers. Neither gender nor family structure moderated the relationship between peer drug models and drug use. However, the association between peer drug models and drug use increased as a function of the level of mother-adolescent distress.
Adolescent↗
Lymphoproliferative disorders: CT findings in immunocompromised children.
OBJECTIVE: The objective was to evaluate the CT imaging appearance, distribution of disease, type of immunocompromised state, and outcome of children with Epstein-Barr virus-induced lymphoproliferative disorders. MATERIALS AND METHODS: Medical records and imaging studies (from four tertiary children's medical centers) were reviewed for pathologically proven cases of lymphoproliferative disorders in patients less than 20 years old. Trends between the CT imaging appearance, distribution, and type of immunocompromised state and prognosis were noted and analyzed with Fisher's exact test. RESULTS: Twenty-seven cases were identified (mean age, 7 years 8 months). Eighteen children had undergone solid organ transplantation (heart, n = 9; liver, n = 7; kidney, n = 2), and four had undergone bone marrow transplantation. Five patients had primary immunodeficiencies. The CT appearance of lymphoproliferative disorders varied and included lymphadenopathy, focal mass or masses, and diffuse infiltration and enlargement of organs without focal mass. The distribution of disease included abdomen (n = 17), chest (n = 10), neck (n = 8), and brain (n = 1). In eight of nine heart transplant recipients, the disease predominantly involved the chest and neck, whereas in all seven liver transplant recipients, the disease was isolated to the abdomen (p = .001). The overall mortality rate of 44% was less related to anatomic extent (multiorgan, 46%; localized, 43%) than to type of immune dysfunction (p = .001): bone marrow transplantation (100%), primary immunodeficiency (80%), heart transplantation (55%), liver transplantation (0%), and kidney transplantation (0%). CONCLUSION: Lymphoproliferative disorders in children had a variable distribution, imaging appearance, and outcome. However, in recipients of solid organ transplants, the disease tended to occur in the anatomic region of the transplant. Mortality rates were more closely related to the type of underlying immune dysfunction than to distribution of disease.
Bone Marrow Transplantation↗
Psychological effects of dietary fat analysis and feedback: a randomized feedback design.
Excess consumption of dietary fat promotes chronic disease such as heart disease and cancer. Dietary analysis and feedback are often used to motivate dietary change; however, little is known about how people process, react to, and use this feedback to change behavior. This study used a randomized feedback design to examine psychological reactions to dietary fat feedback. Subjects were assessed for fat consumption and then randomly assigned to a high, moderate, or low percentage of calories from fat feedback group. Findings indicate that there are strong emotional, cognitive, and behavioral reactions to providing high-fat dietary feedback. Subjects that were told their diets were high in fat reported stronger negative emotional reactions and also reported they had stronger intentions to change than the other two feedback categories. These results are compared with studies providing nonrandomly assigned risk factor feedback.
Adolescent↗
Invited article: helical/spiral CT scanning: a pediatric radiology perspective.
Helical/spiral CT technology has several potential benefits for scanning pediatric patients. These benefits include reduced sedation rates, decreased radiation exposure with scanning at extended pitch, improved image quality, and better three-dimensional and reformatted images. This paper reviews the technical and clinical considerations relevant to scanning the pediatric patient and offers suggestions for protocol development.
Angiography↗
Acute response to inhaled nitric oxide in newborns with respiratory failure and pulmonary hypertension.
OBJECTIVE: Systemic oxygenation is improved by inhaled nitric oxide therapy in some newborns with respiratory failure and pulmonary hypertension. Our results with inhaled nitric oxide were reviewed to determine factors associated with an acute improvement in systemic oxygenation. METHODS: Newborns with oxygenation indices of 25 to 40 were prospectively randomized to receive conventional therapy with or without 20 ppm inhaled nitric oxide. All newborns with oxygenation indices greater than 40 were treated with inhaled nitric oxide. Hemodynamic, blood gas, and Doppler ultrasound measurements were performed before and after 30 to 60 minutes of observation or therapy. The severity of lung disease was classified by the chest radiograph as: (1) normal or focal disease; (2) moderate diffuse disease-diffuse lung disease with well-defined heart borders; or (3) severe diffuse disease-diffuse lung opacification with indistinct heart borders. RESULTS: Heart rate, blood pressure, and ductal diameters did not change. Blood gases and ductal shunting acutely improved only in patients treated with inhaled nitric oxide. Patients with normal lung fields or focal disease had the greatest degree of improvement in systemic oxygenation. Changes in oxygenation were not influenced by gestational age, baseline blood gases, the proportion of right-to-left ductal shunting, prior treatment with a surfactant, or the use of conventional or high-frequency jet ventilation. Collectively, blood gases and ductal shunting did not improve with inhaled nitric oxide in patients with lung hypoplasia or severe diffuse lung disease. Sustained improvement in oxygenation occurred in 87% of patients with oxygenation indices greater than 40 in whom oxygenation indices less than 40 acutely developed after exposure to nitric oxide, whereas 90% of patients in whom oxygenation indices less than 40 did not acutely develop were treated with extracorporeal membrane oxygenation or ultimately died. CONCLUSIONS: Inhaled nitric oxide acutely improves systemic oxygenation in many newborns with respiratory failure and pulmonary hypertension. The diagnosis and chest radiograph are helpful in identifying patients who will have favorable acute responses to therapy. In patients with severe hypoxemia, the need for invasive support with extracorporeal membrane oxygenation may be determined by an acute trial of inhaled nitric oxide.
Acute Disease↗
Reduced need for sedation in patients undergoing helical CT of the chest and abdomen.
Since 15 July 1993, we have used helical CT exclusively in chest and abdomen exams. The purpose of this study was to compare sedation rates in children undergoing conventional and helical CT of the chest and abdomen. Data for all CT examinations of the head (n = 1121), chest (n = 427), and abdomen (n = 315) performed between 1 April 1993 and 31 October 1993 were evaluated. Examinations were divided by anatomic site, patient age, date, whether motion was noted in the radiology report, and whether or not sedation was used. The oldest patient requiring sedation was 5 years old. All examinations in patients 5 years old or less (n = 1048) formed the study group. Because no head CT examinations were done helically, this constituted a control group. Comparisons of motion and sedation rates before and after 15 July 1993 were made with the chi 2 test. There was no statistically significant difference in the sedation rate in the control group (patients having conventional head CT examinations). In contrast, the use of helical technique for chest and abdomen CT coincided with a reduction of the sedation rate from 18% to 10% (P = 0.3). There was no statistically significant difference in reported motion for either head or chest/abdomen examinations over the study period. The implementation of helical CT coincided with a 45% reduction in the sedation rate of patients undergoing CT of the chest and abdomen. At the current volume of CT examinations at our institution, this decrease would result in an estimated 60 fewer sedations per year.
Child, Preschool↗
Comparison of helical and conventional chest CT in the uncooperative pediatric patient.
The objective of this study was to compare the quality of conventional and helical computed tomography (CT) images in children unable to breath-hold. Sixteen patients (age range 1.1-7.5 years) underwent both conventional and helical chest CT on a General Electric HiSpeed Advantage scanner at a mean study interval of 3.8 months. Conventional 0.6-s scans were reconstructed with standard algorithm while 1.0-s helical studies were reconstructed with standard and bone algorithms. Three blinded observers retrospectively evaluated the images. There was no significant difference in motion, image sharpness and anatomic resolution for helical and conventional scans reconstructed with standard algorithm. Furthermore, image sharpness (P < 0.001) and visibility of bronchi (P < 0.001) were improved when helical images were reconstructed with bone algorithm. We conclude that motion artifact severity, image sharpness and anatomic resolution for helical and conventional 0.6-s chest CT are similar when the images are reconstructed with an identical algorithm. Helical CT may be preferable because of the faster examination times and the ability to reconstruct overlapping images as an adjunct for problem solving. Also, with the scanner used, bone algorithm reconstruction can be employed to improve image sharpness and anatomic resolution.
Artifacts↗
Quantification of intravenous contrast-enhanced Doppler power spectrum in the rabbit carotid artery.
In vivo evaluation of Doppler contrast agent (DCA) enhancement has been principally qualitative. To quantitate the enhancement of the Doppler signal by perflubron emulsion, an investigational DCA, the audio-Doppler signal from the rabbit carotid artery was recorded during 0.5-ml/kg incremental doses to a total dose of 2.5 ml/kg. A representation of the recorded signal intensity, the Doppler power spectrum (DPS), was determined using a personal computer and commercially available software package. The dose related enhancement from perflubron emulsion was linear (r = 0.986, p = 0.0124) with a 710% (8.5 dB) overall enhancement at 2.5 ml/kg (p = 0.0001). Significant differences in enhancement could be detected with doses as low as 1.0 ml/kg and compared favorably with observer assessment of dose-related enhancement. This relatively simple method of computer analysis can quantify in vivo Doppler signal intensity and enhancement by perflubron emulsion and may enable quantitative comparisons between different DCAs.
Animals↗
Nontraumatic pediatric musculoskeletal MR imaging: comparison of conventional and fast-spin-echo short inversion time inversion-recovery technique.
PURPOSE: To compare conventional short inversion time inversion-recovery (STIR) with fast spin-echo (FSE) STIR techniques to evaluate suspected nontraumatic musculoskeletal abnormalities. MATERIALS AND METHODS: Thirty STIR and FSE-STIR examinations in 26 pediatric patients with suspected nontraumatic musculoskeletal abnormalities were prospectively evaluated. Qualitative (subjective) and quantitative (five-point rank score) analyses of the images were performed. RESULTS: FSE-STIR was faster than STIR (mean, 2 minutes 25 seconds and 6 minutes 35 seconds, respectively). Fat suppression was slightly better with STIR. Image degradation due to motion was judged similar. Lesion contrast to muscle was slightly better with STIR than FSE-STIR, and lesion contrast to fat was equivalent. Qualitatively, lesion conspicuity was similar: All lesions were seen with both techniques. CONCLUSION: FSE-STIR can replace STIR when an inversion-recovery fat-suppression sequence is desired. Considerable imaging time is saved.
Adolescent↗
MR imaging of bone marrow in children with osteosarcoma: effect of granulocyte colony-stimulating factor.
OBJECTIVE: Granulocyte colony-stimulating factor (GCSF) is used to stimulate myeloid cell production and function in children undergoing chemotherapy for osteosarcoma. We hypothesize that GCSF can cause reconversion of marrow from fatty to hematopoietic and that this change can be detected by MR imaging at sites away from the primary tumor. This benign effect of treatment should not be confused with tumor spread. MATERIALS AND METHODS: MR images of marrow of the affected and contralateral limbs were retrospectively reviewed for 16 patients with osteosarcoma of the femur or tibia; nine of these patients had received GCSF. A grade was assigned to marrow signal intensity at sites away from the tumor, and findings before and after treatment were compared. The validity of MR image interpretation was assessed by comparing the signal intensity of marrow with the histologic appearance of marrow at 19 resection margins. RESULTS: Changes consistent with reconversion were seen on MR images in seven of nine patients who had received GCSF in addition to chemotherapy and in none of seven patients who had received chemotherapy alone. The difference in proportions was statistically significant (p = .006; Fisher's exact test, two tailed). The histologic appearance of marrow at the resection margins agreed with the interpretation of the short-Tl inversion recovery sequence in all cases (100%). CONCLUSION: The findings suggest that GCSF causes changes in the MR imaging appearance of marrow. Histologic correlation supports the hypothesis that these changes are attributable to reconversion from fatty to hematopoietic marrow. Awareness of this finding is important to avoid false-positive diagnosis of marrow metastases.
Adolescent↗
Hematopoietic marrow regeneration in pediatric patients undergoing spinal irradiation: MR depiction.
PURPOSE: To evaluate changes in vertebral marrow signal intensity that occur over time in children undergoing craniospinal radiation therapy, specifically evaluating for the occurrence and timing of marrow regeneration. METHODS: MR images of nine pediatric patients (ages 4 to 12 years) with posterior fossa medulloblastoma who received total spinal irradiation (24 to 40 Gy) and had at least three MR examinations were reviewed. Signal intensity to vertebral body marrow was graded by two pediatric neuroradiologists who were blinded to patient identity and to the timing of the studies. RESULTS: Eight of nine patients demonstrated increasing signal intensity of the vertebral marrow after irradiation, consistent with conversion of hematopoietic to fatty marrow. In each of these patients, this was followed by subsequent decreasing signal intensity in a mottled or peripheral band pattern indicating recovery of hematopoietic marrow. CONCLUSION: Changes in vertebral body signal intensity consistent with marrow reconversion commonly are seen in pediatric patients 11 to 30 months after they undergo total spinal irradiation.
Bone Marrow↗