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Biomedical subjects

R T Brown

Publications and source records attributed to R T Brown.

At least 19 recordsLinked to original sources
PubMed2004

The unexpected preference for the fac-isomer with the tris(5-ester-substituted-2,2'-bipyridine) complexes of ruthenium(II).

The synthesis of a number of new 2,2'-bipyridine ligands, functionalized with bulky ester side groups, is reported (L2-L8). Their reaction with [Ru(DMSO)(4)Cl(2)] gives rise to tris-chelate ruthenium(II) metal complexes which show an unusually high proportion of the fac-isomer, as judged by (1)H NMR following conversion to the ruthenium(II) complex of 2,2'-bipyridine-5-carboxylic acid methyl ester (L1). The initial reaction appears to have thermodynamic control with the steric bulk of the ligands causing the third ligand to be labile under the reaction conditions used, giving rise to disappointing yields and allowing rearrangement to the more stable facial form. DFT studies indicate that this does not appear to be as a consequence of a metal centered electronic effect. The two isomers of [Ru(L1)(3)](PF(6))(2) were separated into the two individual forms using silica preparative plate chromatographic procedures, and the photophysical characteristics of the two forms compared. The results appear to indicate that there is no significant difference in both their room temperature electronic absorption and emission spectra or their excited state lifetimes at 77 K.

Journal Article↗
PubMed2002

Psychosocial adjustment and peer competence of siblings of children with Attention-Deficit/Hyperactivity Disorder.

Preliminary data examined the relationships between mothers, their sons with Attention-Deficit/Hyperactivity Disorder (ADHD), and younger siblings. We hypothesized that the conflict between the mother and the son with ADHD would also occur in the relationship between the child with ADHD and the younger sibling. Significant associations were found among ADHD behaviors, family conflict variables, conflict in the relationship between mother and child with ADHD, conflict in the relationship between mother and younger sibling, and conflict in the relationship between the child with ADHD and the younger sibling. Further, significant associations were found between behavior symptoms associated with ADHD and more problematic family relationships. Of particular interest was the finding of an unexpected inverse association between siblings' peer competence and mother-ADHD conflict; specifically, that conflict occurring at home from ADHD accounted for a greater percentage of the variance in peer competence as rated by teachers. Recommendations are made for future research with larger samples, alternative designs, older siblings, and fathers.

Adaptation, Psychological↗
PubMed2001

Poor school and cognitive functioning with silent cerebral infarcts and sickle cell disease.

The authors evaluated education attainment and neuropsychological deficits in children with sickle cell disease (SCD) and silent cerebral infarcts. Children with silent infarcts had twice the rate of school difficulties as children without infarcts. Eighty percent of silent infarct cases had clinically significant cognitive deficits, whereas 35% had deficits in academic skills. Children with silent cerebral infarcts show high rates of poor educational attainment, cognitive deficits, and frontal lobe injury. Poor school performance in SCD is one indicator of silent infarcts.

Adolescent↗
PubMed2001

Neuropsychological aspects of pediatric sickle cell disease.

Sickle cell disease (SCD), a class of genetic disorders characterized by abnormal, sickled red blood cells, is a chronic illness that results in progressive cerebrovascular disease. Neurocognitive sequelae of clinically apparent cerebrovascular accidents in children with SCD are characterized by pervasive impairments, including decrements in general intellectual functioning, language and verbal abilities, visual-motor and visual-spatial processing, memory, academic achievement, and processing of subtle prosodic information. In contrast, subtle neurocognitive deficits in the areas of attention and concentration, executive function, and visual-motor speed and coordination appear to be associated with silent infarcts that are not necessarily detected on physical examination. Investigation of the disease course and associated neurocognitive sequelae suggest a disease-specific model of neuropsychological impairment. Recommendations are made for clinical and research efforts in the field of pediatric neuropsychology.

Anemia, Sickle Cell↗
PubMed2001

Association of parental psychological and behavioral factors and children's syncope.

The authors examined the associations between parental variables and child syncope (fainting). Children ages 7 to 18 years undergoing tilt-table testing for neurocardiogenic syncope (NCS) at a pediatric cardiac center served as participants (N = 56). Results revealed that fathers' shortness of breath and overall psychological distress were significantly related to syncope frequency and emergency room (ER) visits for girls. Mothers' overall psychological distress, depressive symptoms, and shortness of breath were associated with boys' frequency of syncope and ER visits. Fathers' psychological factors were highly correlated with syncope for the children diagnosed negative for NCS. The frequency of children's syncope was higher in stepfamilies than in homes with both biological parents, and the correlations between children's syncope and the stepfathers' psychological symptoms were greater than for the children and their biological fathers in intact families. The role of parental psychological factors on child syncope is supported.

Adolescent↗
PubMed2001

Self-assessment in clinical health psychology: a model for ethical expansion of practice.

Society expects autonomous professions to ensure the competency of it practitioners, and professions should facilitate the continuing education and training of its members. Given the shift from psychology as a mental health profession to that of a health profession, the authors propose a self-assessment model for the individual practitioner to gauge his or her readiness to provide professional service in expanded areas of practice. This model could also be useful to the American Psychological Association, state psychological associations, and other purveyors of continuing education programs in systematically developing postgraduate experiences. A template for self-assessment that reflects well-accepted core domains of knowledge and skills is presented.

Education, Continuing↗
PubMed2001

Unilateral diaphragmatic palsy in association with a subclavian vein thrombus in a very-low- birth-weight infant.

Phrenic nerve paralysis due to iatrogenic injury is not uncommon in neonates. We report an unusual case of acquired unilateral paralysis of the diaphragm in a very-low-birth-weight infant, associated with a thrombus secondary to percutaneous subclavian vein catheterization. Conservative management resulted in complete resolution of the paralyzed diaphragm.

Catheterization, Central Venous↗
PubMed2001

Situational analysis of parenting problems for caregivers of children with sickle cell syndromes.

A situational analysis of problematic situations was conducted for 37 caregivers of children with sickle cell disease (SCD) who ranged in age from 5 to 13 years. Participants responded to a semistructured interview related to caring for a child with SCD. The interview included the domains of medication adherence, nutrition, minimizing and coping with pain episodes, social problems, academic difficulties, and children's expression of negative feelings related to having SCD. Caregivers described a total of 356 problems. Almost all caregivers reported experiencing problems with their children's nutrition (n = 35), minimizing pain episodes (n = 34), and their children expressing feelings about having SCD (n = 33). Moderately challenging and emotionally upsetting problems were reported for coping with pain episodes. The total number of problems was significantly higher for boys than for girls. Nutrition issues were more frequently reported for younger children. Findings have salient clinical implications for the care of children with SCD.

Activities of Daily Living↗
PubMed2001

Prevalence and assessment of attention-deficit/hyperactivity disorder in primary care settings.

Research literature relating to the prevalence of attention-deficit/hyperactivity disorder (ADHD) and co-occurring conditions in children from primary care settings and the general population is reviewed as the basis of the American Academy of Pediatrics clinical practice guideline for the assessment and diagnosis of ADHD. Epidemiologic studies revealed prevalence rates generally ranging from 4% to 12% in the general population of 6 to 12 year olds. Similar or slightly lower rates of ADHD were revealed in pediatric primary care settings. Other behavioral, emotional, and learning problems significantly co-occurred with ADHD. Also reviewed were rating scales and medical tests that could be employed in evaluating ADHD. The utility of using both parent- and teacher-completed rating scales that specifically assess symptoms of ADHD in the diagnostic process was supported. Recommendations were made regarding the assessment of children with suspected ADHD in the pediatric primary care setting.

Attention Deficit Disorder with Hyperactivity↗
PubMed2001

Behavioral teratology/toxicology: how do we know what we know?

Knowledge about human behavioral teratology/toxicology must necessarily be limited by the methods that can ethically be used. Research in the field is an enterprise calling for tolerance for uncertainty if not chaos. Among the main points of this paper are: (a) Kaufman's criticisms of research on low blood-lead level (BLL) and children's IQ are generally valid and apply to virtually all human natural-groups research; (b) Relative to some contexts, research on low BLL on children's IQ is exemplary; (c) Relative to other contexts, the conclusion that low BLL have linear effects is well supported; (d) Owing to necessary design limitations, all natural-groups studies have shortcomings; (e) Inference of causality is uncertain under any conditions; and (f) Some authors readily leap from molehills of data to mountains of causal conclusions.

Comment↗
PubMed2000

Constitutive activation of STAT3 is associated with the acquisition of an interleukin 6-independent phenotype by murine plasmacytomas and hybridomas.

Interleukin 6 (IL-6), the major growth factor for myeloma cells, signals through the activation of signal transducers and activators of transcription (STAT) proteins. An important step in the malignant progression of murine plasmacytomas is the transition from dependence on IL-6 to a state of IL-6 independence. To elucidate the mechanism whereby IL-6 independence occurs, intracellular signaling events elicited by IL-6 in both IL-6-dependent and -independent plasmacytomas and hybridomas were compared. It was found that STAT3, a key molecule involved in IL-6 signaling, was constitutively activated and phosphorylated in IL-6-independent cell lines compared to the IL-6-dependent cells. Further comparison of upstream signaling pathways revealed that JAK-1 was constitutively present in anti-phosphotyrosine immunoprecipitates of IL-6-independent cells; gp130 was constitutively phosphorylated in a subset of IL-6-independent plasmacytomas, whereas other IL-6-independent lines showed no detectable gp130 phosphorylation in the absence of exogenous IL-6. Secretion of a factor capable of supporting the growth of IL-6-dependent cells was observed in one of the IL-6-independent plasmacytomas, but not in others, making an autocrine mechanism an unlikely explanation for IL-6 independence. These findings provide evidence that the constitutive activation of STAT3, either in the absence of detectable receptor-proximal events or associated with the concomitant activation of gp130, can contribute to the process of IL-6 independence.

Animals↗
PubMed2000

Risk-resistance adaptation model for caregivers and their children with sickle cell syndromes.

This investigation examined the risk-resistance adaptation model for children with sickle cell disease and their primary caregivers. Participants were 55 children, ranging in age from 5 to 16 years with a mean age of 9 years 2 months, diagnosed with sickle cell disease and their primary caregivers, recruited from a university medical center. Measures included adjustment (i.e. primary caregiver and child adjustment), risk factors (i.e. disease and disability, functional independence, and psychosocial stressors), resistance factors (i.e. intrapersonal health locus of control, social-ecological), and stress processing (coping). Primary caregivers' adjustment was associated with developmental coping, changeR2 = .08, and child adaptation was associated with an internal health locus of control, changeR2 = .22. An indirect effect of primary caregivers' coping on child adjustment was found through influence on primary caregivers' adjustment, changeR2 = .11. The findings support research among other chronically ill populations that suggests an association between coping and disease adjustment. The results were interpreted to support the use of theoretically driven models in predicting the adaptation of children with chronic illness and adjustment in their caregivers.

Adaptation, Psychological↗
PubMed2000

Acute and chronic pelvic pain in female adolescents.

Pelvic pain in adolescents is a common and frequently puzzling symptom with many possible causes. The patients who suffer from this symptom, by and large, have diagnosable and treatable causes. A sensible, studied, and progressive approach by a warm and accepting physician usually is the key to successful diagnosis and management of this condition.

Acute Disease↗
PubMed2000

Allergic gastroenteropathy in preterm infants.

OBJECTIVES: To determine the clinical presentation, histopathologic features, and outcome of biopsy-proven allergic gastroenteropathy (AGE) in preterm infants. We hypothesized that AGE is a more frequent cause of gastrointestinal disease in this population than previously suspected. STUDY DESIGN: The retrospective portion of the study, from 1992 to 1997, included preterm infants <37 weeks' gestation who underwent biopsy because of suspected AGE. The prospective portion, from January to December 1998, included 20 infants undergoing endoscopy and biopsy because of suspected AGE. RESULTS: Twenty-five infants (12 retrospective/13 prospective) with mean gestational age of 29 weeks at birth and mean postnatal age at diagnosis of 78 days were diagnosed with AGE. Three clinical patterns of presentation were noted: group 1, gastroesophageal reflux disease (n = 5); group 2, non-specific feeding intolerance (n = 8); and group 3, lower gastrointestinal bleeding (n = 12). Ten patients had negative biopsy findings (3 retrospective/7 prospective) and had clinical features indistinguishable from those of groups 1 and 2. Patients in group 3 were most likely to have positive biopsy findings (12 of 12). Fifteen patients responded to a casein hydrolysate formula, and 10 patients required an amino acid-based formula. Patients with AGE who had eosinophilic infiltration and villous atrophy took longer to recover than those with eosinophilic infiltration alone (P <.03). Subsequently, most have tolerated formula challenges and are currently tolerating cow's milk. CONCLUSIONS: AGE may be an under-recognized cause of gastrointestinal symptoms in preterm infants. Confirmation with endoscopy and biopsy can be done safely and provides the basis for appropriate dietary management.

Follow-Up Studies↗
PubMed2000

Identity in adolescent survivors of childhood cancer.

OBJECTIVE: To investigate identify formation among adolescent survivors of childhood cancer. Family functioning, perceived emotional support from family and peers, life stress, and anxiety produced by the cancer experience also were examined as they influenced identity development. METHOD: Participants were 52 adolescent survivors and their mothers recruited from a medical center and 42 healthy adolescent counterparts and their mothers recruited from the community. RESULTS: A greater frequency of survivors than their healthy peers was found within the foreclosed identity status. Factors associated with the foreclosed identity status included the cancer diagnosis, symptoms of posttraumatic stress disorder (PTSD), and family functioning characterized by greater levels of conflict. CONCLUSIONS: Data were interpreted to suggest that the foreclosed identity status may serve a protective function in assisting survivors to cope with the stressors of the cancer experience.

Adolescent↗
PubMed2000

Adolescent sexuality at the dawn of the 21st century.

Human sexuality can be defined as including the physical characteristics of and capacities for specific sex behaviors, together with psychosocial values, norms, attitudes, and learning processes that influence these behaviors. It also includes a sense of gender identity and related concepts, behaviors, and attitudes about the self and others as women or men in the context of one's society. At the dawn of the new century, adolescent sexuality remains a topic of concern to adults throughout the world. This concern is not unique to this new age. In each era of recorded history, adults have been concerned about adolescent sexual behavior, particularly sexual intercourse and its consequences. Things have not changed all that much in the realm of adolescent sexual behavior. What has changed is our ability to prevent the serious consequences of this behavior and, hopefully, to help adolescents avoid behaviors that put them at risk for the negative consequences of expressing their burgeoning sexuality. This article reviews the major influences on adolescents developing' sexuality, the data on adolescent sexual activity, some tips on caring for adolescents comprehensively, and ends with some predictions of how this issue will be addressed in the new century.

Adolescent↗