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Biomedical subjects

R W Warren

Publications and source records attributed to R W Warren.

At least 19 recordsLinked to original sources
PubMed2001

Sorption and transport of radionuclides by tumbleweeds from two plastic-lined radioactive waste ponds.

Previous research has examined the uptake of radionuclides by tumbleweeds growing in contaminated soils, but none has heretofore examined the sorption of radionuclides to tumbleweeds blowing into radioactively contaminated water. Three tumbleweed species; Russian thistle (Salsola kali), Jim Hill mustard (Sisymbrium altissimum) and summer cypress (Kochia scoparia) blow in, and out of, two plastic-lined radioactive wastewater ponds, constructed in 1993 on the US Department of Energy's Idaho National Engineering and Environmental Laboratory in southeast Idaho. This research quantified radionuclide sorption to tumbleweeds, tumbleweed movement from the ponds, and determined radionuclide transport from the ponds. Average plant/water concentration factors associated with tumbleweeds taken from the ponds ranged from 5 for 152Eu to over 9000 for 54Mn. Based on changes in tumbleweed numbers and average concentrations associated with them, 66.2 MBq were estimated to have been transported from the ponds via tumbleweeds between 18 October 1994 and 8 November 1996. This amounts to about 0.01% of the non-tritium and 0.0002% of the tritium activity released to the ponds through 8 November 1996. A power function best described the radionuclide buildup curve for tumbleweeds submerged in the ponds. Visually marked tumbleweeds traveled from the ponds in the predominant wind direction a maximum of 737 m. Management practices which may reduce the number of tumbleweeds blowing both into and out of contaminated ponds are discussed.

Adsorption↗
PubMed1999

Risks of endoscopy in hospitalized pediatric patients with collagen vascular diseases.

BACKGROUND: The gastrointestinal manifestations of the collagen vascular diseases have been well described in the pediatric population. These patients frequently have symptoms that constitute indications for endoscopy. However, the risks and benefits of endoscopy in this population have not been examined. METHODS: A retrospective review of all patients with collagen vascular diseases hospitalized during a 7-year period was undertaken, and those patients who underwent endoscopy were identified. RESULTS: Nine patients (5%) underwent endoscopic procedures (eight upper and three lower endoscopy). Complications and outcomes were analyzed. Indications for endoscopy included abdominal pain, gastrointestinal (GI) bleeding, and/or vomiting and diarrhea. Two patients had complications that required surgery within 1 day of the endoscopic procedure. One of these patients subsequently died with GI bleeding. Five of the nine patients had changes in their management after endoscopy. Helicobacter pylori infection was identified and treated in two patients. Three patients had esophagitis or gastritis and acid suppression treatment was started or optimized. Vasculopathy was present in the patients who had complications. CONCLUSIONS: This series suggests that endoscopy can provide useful information for the management of the pediatric patient with GI symptoms and collagen vascular diseases. However, because serious and potentially life-threatening complications can occur, great care is needed in evaluating the risk/benefit ratio of endoscopy in these patients.

Adolescent↗
PubMed1999

Health status of children with special health care needs: measurement issues and instruments.

The methods for measuring health care outcomes and monitoring the health status of the child with a chronic health condition must be available, accessible, and meaningful. This review was evoked by this need to identify reliable and valid instruments for measuring the health status of children with special health care needs. The objectives are as follows: (1) to review the methodologic and substantive issues related to the selection of instruments and (2) to identify those instruments available currently for collecting data regarding health status of children with special health care needs. A Medline search of the literature published since 1966 through 1998 and restricted to human subjects and the English language was conducted. Indexing terms included health status, quality of life, outcome assessment, functional status, and patient satisfaction. Multiple reviewers selected instruments based on their usefulness in clinical settings as generic, disease nonspecific, child health status instruments. Few instruments were identified that can be used by pediatricians for tracking and monitoring the health status of children with special health care needs. In conclusion, to progress in the field of outcomes measurement of children with special health care needs, it will be necessary to develop new measurement tools. These instruments must (1) provide valid and reliable information on health status; (2) be useful in guiding the management of patients; and (3) not be a burden for physicians, patients, or patient's families.

Adolescent↗
PubMed1999

Optic disc edema in neonatal onset multisystem inflammatory disease (NOMID).

PURPOSE: To inform ophthalmologists about neonatal onset multisystem inflammatory disease (NOMID), a rare condition with ophthalmologic manifestations. METHODS: We report a single case of NOMID with optic disc edema. RESULTS: A 28-month-old child with neonatal rash, arthropathy, central nervous system (CNS) involvement, and optic disc edema was diagnosed with NOMID. CONCLUSIONS: The finding of posterior uveitis or optic disc edema in a child with juvenile onset arthritis may allow the differentiation of NOMID from juvenile rheumatoid arthritis.

Age of Onset↗
PubMed1998

Increasing incidence of childhood class V lupus nephritis.

OBJECTIVE: Class V lupus nephritis (LN) is reported to occur in 0-23% of patients with LN. To better characterize pediatric LN, we determined at a single center (1) the relative frequency of Class V LN on first and serial biopsies, (2) the frequency of transformation between LN classes on serial biopsies, (3) types of treatment received and outcome to date of different classes of LN. METHODS: All pediatric renal biopsies from 1985 to the present performed for diagnosis and classification of suspected LN were reviewed. Biopsy results were grouped into 2-3 year time intervals to assess trends in the distribution of WHO class diagnoses over time. RESULTS: Sixty patients underwent 97 renal biopsies. Class V LN was present in 28% (17/60) of patients on first biopsy, and in 37% (22/60) on most recent biopsy. Class V LN on first biopsy increased from 17% (8/46) before 1995 to 64% (9/14) after 1995 (p < 0.001). Age at presentation, age at biopsy, time to biopsy, and types of treatment did not differ before and after 1995. Transformation to Class V LN occurred in 19% (5/27) of patients having repeat biopsies. No transformation from Class V LN occurred on repeat biopsy. Renal outcome was available in 48 patients with followup of 4.7 +/- 3.2 years for Class V LN, and 5.2 +/- 2.4 years for non-Class V LN. Five percent (1/20) of Class V LN patients had renal dysfunction or had died compared to 21% (6/28) of non-Class V LN patients (p = NS). CONCLUSION: We found (1) a greater frequency of Class V LN than has been reported, (2) a recent increase in the incidence of Class V LN at our institution, (3) frequent transformation between classes on serial biopsies, and (4) no regression of Class V lesions in patients who had repeat biopsies.

Adolescent↗
PubMed1997

Rheumatologic aspects of pediatric cystic fibrosis patients treated with fluoroquinolones.

BACKGROUND: The recommended and approved use of fluoroquinolones, including ciprofloxacin, is limited to adult patients because of concerns about the association of joint toxicity in young animals with quinolone administration and rare reports of joint complaints or findings in humans. Despite these warnings some quinolones have been used in children for many years, with seemingly minimal joint sequelae. OBJECTIVE: This brief review will clarify the association of quinolones with arthropathy, particularly ciprofloxacin because of its widespread use, and subsequently discuss the problem of defining that association in a population of children with cystic fibrosis. RESULTS: Examination of available clinical data to date provides no absolute evidence that ciprofloxacin induces significant arthropathy in children, in contrast to data reported in some animal species. Specifically short term ciprofloxacin-induced joint toxicity appears to be low in cystic fibrosis patients who have a significant background prevalence of arthralgias and arthritis. However, the level of detection of joint toxicity in these small trials may be insufficient to define rare or late adverse effects. CONCLUSIONS: Ciprofloxacin-associated arthropathy appears to occur infrequently, particularly in children with cystic fibrosis.

Animals↗
PubMed1995

Bridging the "med-ed gap" for students with special health care needs: a model school liaison program.

A successful school experience is critical to the development of all children, particularly in the areas of academic achievement, regular school attendance, and social competency. Vulnerabilities in achieving each of these three goals have been documented among students with special health care needs (SSHCN), and ascribed to the influence of their health-related disabilities. Despite recognition of these vulnerabilities, barriers still exist to successful integration of SSHCN into educational settings. A key barrier to successful integration involves poor linkages between the health and education systems. This article describes a model linkage system--the School Liaison Program at Texas Children's Hospital, developed as a U.S. Dept. of Health and Human Services Maternal and Child Health Bureau Special Project of Regional and National Significance. The program provides educational liaison services between the largest pediatric hospital in the United States and school districts in the fourth largest city. A description of the linkage system emphasizes interdisciplinary staffing by both special educators and health providers. The model for educational liaison service delivery presented includes the elements of eligibility, assessment of the educational implications of illness, plan development and referral, involvement in educational placement, and monitoring. Resources for integrating SSHCN into educational settings are suggested.

Adolescent↗
PubMed1994

Evolution of homeotic gene regulation and function in flies and butterflies.

It has been proposed that the evolution of homeotic genes parallels, and to some degree directs, the evolution of segment diversity in the myriapod-insect lineage. But the discovery of discrete Antennapedia complex (ANT-C) and bithorax complex (BX-C) gene members in crustacea, chelicerates, annelids and various insects, as well as in vertebrates, indicates that the expansion and diversification of homeotic genes preceded the diversification of arthropods and insects. How, then, have these genes influenced the evolution of body plans? To address this question, we now examine homeotic gene expression and regulation in butterflies (Lepidoptera), which, unlike flies, possess larval abdominal limbs and two pairs of wings. We show that the difference in larval limb number between these insects results from striking changes in BX-C gene regulation in the butterfly abdomen, and we deduce that the wing-patterning genes regulated by Ultrabithorax have diverged in the course of butterfly and fly evolution. These findings have general implications for the role of homeotic genes in animal evolution.

Amino Acid Sequence↗
PubMed1994

Pediatric rheumatic diseases.

The rheumatic diseases of childhood are a relatively common and extraordinarily diverse group of illnesses; nevertheless, they are at least distantly related by similarities of immunodysregulation. These pathophysiologic relationships are reflected in affected children in similarities of historical, physical, and laboratory data as well as therapeutic intervention.

Adrenal Cortex Hormones↗
PubMed1991

Disease experience and psychosocial adjustment in children with juvenile rheumatoid arthritis: children's versus mothers' reports.

Adjustment in children with juvenile rheumatoid arthritis (JRA) has been evaluated most frequently by parental or teacher reports and with reference to disease severity. In this study, 38 children, ages 7 to 13 with JRA, and their mothers were interviewed. Modest correlations were found between children and mothers in their assessments of children's perceived competence in several domains (i.e., athletic competence, social acceptance, physical attractiveness, and global self-worth) and in their perceptions of how JRA is experienced by children and families. Children's perceptions of the disease experience were significantly correlated with the four measures of perceived competence, even after controlling for disease severity. The results highlight the importance of cross-validating parental reports with children's self-reports, and demonstrate the need to consider variables other than disease severity--in particular how JRA is interpreted by children--in predicting their adjustment.

Adaptation, Psychological↗
PubMed1990

Nasal radioiodine activity: a prospective study of frequency, intensity, and pattern.

The nose has been reported as a site of radioiodine accumulation on 131I whole-body scintigraphy. To determine the frequency, intensity, and pattern of nasal radioiodine accumulation, a prospective study was performed on 21 patients referred for 131I whole-body scintigraphy during a 26-mo interval. All patients were dosed with 5 mCi (18.5 MBq) of 131I p.o., and imaged 72 hr later. Ninety-five percent (20/21) of patients had nasal radioactivity greater than background, and in 75% (15/20) of positive patients the pattern of activity was round. Clinical follow-up of these patients has shown no evidence of tumor involvement in the nasal area. We conclude that nasal radioiodine activity is a normal finding. Radioiodine uptake in the nasal area, without clinical suspicion of metastatic disease, should not be considered a criterion for surgical intervention or radioiodine therapy.

Adult↗
PubMed1987

Relationship of the genes for Chediak-Higashi syndrome (beige) and the T-cell receptor gamma chain in mouse and man.

The genetic linkage of Chediak-Higashi syndrome and its murine analog, beige (bg), to the T-cell receptor (TCR-gamma) gamma chain gene is further defined. Previous studies using recombinant inbred strains of mice demonstrated that the murine bg gene is genetically linked to a murine TCR-gamma gene. We report that in the mouse the frequency of recombination between these two markers is 0.025. Further, we tested the hypothesis that these two genes are linked in the human genome by analyzing restriction fragment length polymorphisms (RFLPs) in five families with children afflicted with Chediak-Higashi syndrome. In three families, RFLPs in TCR-gamma genes were inherited discordantly from Chediak-Higashi syndrome, demonstrating nonlinkage. We postulate that there is an evolutionary chromosomal breakpoint between the bg gene and the TCR-gamma gene.

Animals↗
PubMed1987

Stochastic control of anti-Sm autoantibodies in MRL/Mp-lpr/lpr mice.

MRL/Mp-lpr/lpr autoimmune mice consistently show an approximately 25% incidence of the systemic lupus erythematosus marker autoantibody anti-Sm. In the present report, we show that the failure to find anti-Sm antibodies in three-quarters of 5-mo-old MRL/lpr mice was not an artifact of an insensitive assay, but rather that the mice fell into two populations as regards their anti-Sm positivity. Based on an extensive analysis of the incidence of anti-Sm positivity in 5-mo-old mice according to their cage of residence, we found no evidence for genetic, environmental, or parental influences on the propensity of an individual animal to become anti-Sm positive. Also, the gender of the mouse, its Sm antigen level, or its length of survival were not related to anti-Sm antibody, nor was the anti-Sm antibody status of either parent. Some animals became anti-Sm positive after 5 mo of age, but this was less likely than becoming positive before 5 mo of age. Finally, a survey of 205 autoimmune C57BL/6-lpr/lpr mice confirmed the uniqueness of the MRL background for this autoantibody response. These results together indicate that the possibility of making anti-Sm antibodies is under genetic control, but that the expression of this capability in an individual animal is governed by stochastic events. We hypothesize further that such random processes may involve the expression of particular immunoglobulin variable-region genes combined with mechanisms of extensive somatic mutation or positive feedback amplification, which would transmute an initial monoclonal response into an eventual polyclonal one.

Animals↗
PubMed1986

The immunologic basis of lupus.

This article reviews the immunologic basis of systemic lupus erythematosus. It covers basic immunologic abnormalities, possible role of diet in autoimmune diseases, and the basis for specific abnormalities, such as renal and central nervous system disease.

Animals↗