Biomedical subjects

J Byrnes

Publications and source records attributed to J Byrnes.

11 recordsLinked to original sources

PubMed2006

Examination of behavioral deficits triggered by targeting Bdnf in fetal or postnatal brains of mice.

Human and animal studies have implicated brain-derived neurotrophic factor (BDNF) in the etiology of psychiatric disorders. It is expressed in limbic regions of the brain associated with the regulation of emotionality during fetal development and in the adult animal. To further our understanding of the role of BDNF in the modulation of mood and to distinguish its prenatal and postnatal functions, we investigated and contrasted behavioral changes elicited by its depletion from fetal or postnatal brains of mice. Two corresponding lines of BDNF conditional knockout mice were subjected to a battery of behavioral tests assessing locomotor, depressive, aggressive and anxiety-related behaviors. We found that both lines of mutants were dramatically hyperactive during the light and dark cycles and hyperaggressive. They also exhibited a depression-like phenotype in the tail suspension test but not in the forced swim test. Interestingly, depletion of BDNF from the fetal brain had more pronounced effects on aggressive and depressive-like behaviors and led to deficits in 5-HT(2A) receptor content in the medial frontal cortex, highlighting the importance of this neurotrophin during development. We conclude that expression of BDNF both pre- and postnatally is essential for normal modulation of behavior by neural circuits in the adult animal.

Aggression↗

PubMed2003

Ligand density modulates eosinophil signaling and migration.

Eosinophils are a major component of the inflammatory response in persistent airway inflammation in asthma. The factors that determine the retention of eosinophils in the airway remain poorly understood. Elevated levels of fibronectin have been observed in the airway of patients with asthma, and the levels correlate with eosinophil numbers. To determine if fibronectin density modulates eosinophil function, we investigated the effect of fibronectin and vascular cell adhesion molecule 1 (VCAM-1) density on eosinophil migration and signaling via the p38 and extracellular regulated kinase (ERK)-mitogen-activated protein kinase (MAPK) signaling pathways. There was a dose-dependent inhibition of eosinophil spreading and migration on increasing concentrations of fibronectin but not VCAM-1. In addition, activation of p38 MAPK was inhibited at high fibronectin but not high VCAM-1 concentrations, and ERK activity was slightly reduced at high VCAM-1 and fibronectin concentrations. Together, the results demonstrate that fibronectin but not VCAM-1 inhibits eosinophil migration and signaling.

Adult↗

PubMed1995

Differential transcription efficiency of two Ig VH promoters in vitro.

Each Ig variable region gene segment is transcribed from its own unique promoter. While all of these promoters share common consensus elements that contribute to the B cell-specific expression of these genes, the DNA sequence of each promoter is distinct. In this study, we have directly compared the transcription efficiencies of two murine heavy chain (VH) promoters in a murine B cell in vitro transcription system. We found that the promoters differed in both transcription efficiency and the ability to bind specific protein complexes. While some of the transcription differences may be attributed to differences in basal promoter elements, the spacing between the octamer and the heptamer consensus elements was found to be important. Others have reported a direct correlation between transcription efficiency and the probability that individual variable region gene segments will rearrange. Our studies may be of direct importance to those interested in identifying B cell-specific transcription factors and may ultimately help to explain differences in the expression of some VH gene segments.

Animals↗

PubMed1995

Integrating outcomes measurement into clinical practice improvement across the continuum of care: a disease-specific episode of care model.

This article describes a model for incorporating outcomes measurement into a comprehensive, continuum-wide clinical practice improvement program developed at Lovelace Health Systems (Albuquerque, N.M.). Created in 1993, the Lovelace Episode of Care Program currently includes nine disease-specific multidisciplinary teams that are working to improve care by addressing such issues as severity, appropriateness, efficiency, continuous quality improvement indicators, practice guidelines, care maps, and outcomes. Key features and advantages of the model are discussed, as well as implementation issues, successes, lessons learned, program restructuring and improvement, and applicability of the framework across diseases and health organizations.

Comprehensive Health Care↗

PubMed1995

Quality-of-Life Issues Associated With the Treatment of Prostate Cancer.

The incidence of prostate cancer in the United States has dramatically increased over the last several years. As a result of prostate-specific antigen testing, many more men have localized, asymptomatic prostate cancer at the time of initial diagnosis. Treatment options for patients with prostate-confined adenocarcinoma of the prostate include observation, radical prostatectomy, external beam radiotherapy, radioactive prostate implantation, hormonal therapy, cryotherapy, and various combinations of the above modalities. Quality of life can be affected by the tumor and by any of the hormonal, surgical, or radiotherapeutic interventions. These treatments raise complex and multidimensional issues. Although quality-of-life issues are becoming integral and important components of clinical research in prostate cancer, many challenges in research and practice remain.

Journal Article↗

PubMed1989

Arrangement of repetitive sequences in the genome of herpesvirus Sylvilagus.

Herpesvirus sylvilagus is a lymphotropic (type gamma) herpesvirus of cottontail rabbits (Sylvilagus floridanus). Analysis of virion DNA of herpesvirus sylvilagus has revealed that the genome consists of one stretch of about 120 kilobase pairs of internal, unique DNA flanked by a variable number of 553-base-pair tandem repeats. The G + C content of the repetitive DNA is extremely high (83%), as determined by sequencing. The organization of the herpesvirus sylvilagus genome is, therefore, similar to that of the primate lymphotropic viruses herpesvirus saimiri and herpesvirus ateles.

Base Sequence↗

PubMed1988

Dialysis in the management of pregnant patients with renal insufficiency.

Successful pregnancy in patients on dialysis is uncommon because of a high rate of infertility and complications. The use of hemodialysis to manage pregnant patients needing dialysis has been well reported. However, to our knowledge, only 2 previous cases of pregnant patients using chronic ambulatory peritoneal dialysis (CAPD) have been reported. We discuss 14 pregnancies in 13 women in whom dialysis was used in the management of their pregnancies. Ten pregnancies were successful. Included are 5 successful pregnancies out of 8 managed with CAPD or chronic cycling peritoneal dialysis (CCPD). In comparing the cases managed with CAPD to those managed with hemodialysis, CAPD seems to offer several advantages. These include a more constant biochemical and extracellular environment for the fetus, higher hematocrit levels, infrequent episodes of hypotension, and no heparin requirement. In addition, intraperitoneal insulin facilitates the management of blood glucose in diabetics, and intraperitoneal magnesium facilitates the management of premature labor. Infection, loss of intraperitoneal volume, and loss of peritoneal clearances for solutes and water were not found to be problems.

Adult↗

PubMed1986

Aortic root abscess. Initial experience using magnetic resonance imaging.

The detection of aortic root abscess by magnetic resonance imaging has not been described previously. We report a patient with an aortic root abscess that was successfully diagnosed by magnetic resonance imaging and echocardiography. Computed tomography failed to detect the abscess. The patient recovered with antibiotic therapy. Based on this case and other reports in the literature, we advocate treating similar patients without surgery. We recommend magnetic resonance imaging as an investigational method where the diagnosis of aortic root abscess is ambiguous.

Abscess↗

PubMed1982

Sinus histiocytosis with massive lymphadenopathy: a case with unusual skin involvement and a therapeutic response to vinblastine-loaded platelets.

A patient with sinus histiocytosis with massive lymphadenopathy had unusual skin lesions and progressive internal involvement. Both aspects responded dramatically to the administration of vinblastine-loaded platelets. Vinblastine-loaded, idiopathic thrombocytopenic purpura antibody-coated platelets are a rationale therapy for a disease characterized by the presence of actively phagocytosing histiocytes.

Antibodies↗

PubMed1980

The effects of short- and long-term exposure of chick embryos to neutral red on the frequency of sister-chromatid exchange.

The chick embryo was used to study the effects of neutral red (NR) on the frequency of sister-chromatid exchange (SCE) in specific tissues exposed to this mutagen for short and long periods as development proceeded. In short-term trials, aqueous NR at doses of 10, 25 and 100 micrograms was injected in 3-day and 6-day embryos. In each case, embryos were also treated with 5-bromodeoxyuridine (BrdU) for a 24-h period (two cell cycles) and harvested at 4 days and 7 days, resp. A long-term exposure (about 8 cell cycles) was achieved by exposing embryos to NR from day 3 to day 7 of incubation. At a NR dose of 25 micrograms, the chronic exposure resulted in a doubling of the rate of SCE (11.4/cell) over that observed in embryos exposed for only 24 h at either days 3-4 (6.0/cell) or days 6-7 (6.0/cell). At 100 micrograms of NR, the same relationship held with SCE rates of 14.2/cell for the chronic exposure versus rates of 8.0/cell (3-4 days) and 6.9/cell (6-7 days). At 10 micrograms of NR, no such accumulation of SCE occurred upon long-term treatment. These results show an enhanced SCE response upon growth of embryonic cells in the presence of NR for several days. This may be the result of the persistence of past lesions with the addition of more lesions upon continued exposure to NR.

Animals↗

PubMed1973

Development of syntax in a retarded girl using procedures of imitation, reinforcement, and modelling.

Three experiments demonstrated the development and generalized use of a singular and plural declarative sentence in a child initially lacking sentence form responses. In each experiment, an adult(s) served as a language model(s), and consequences (sweets) were provided for imitation of the model. During training trials, an item(s) was displayed first to the model(s) then to the subject; these displays were accompanied by requests to label the item(s). Generalization was assessed by a number of probe trials that were periodically interspersed among training trials. During these trials, the subject was requested to label the displayed item(s) without any preceding labelling response from the model. Using these procedures, generalized use of a singular sentence ("That is one-") resulted in Experiment I, and generalized use of a plural sentence ("These are two-") resulted in Experiment II. In Experiment III, two models (a singular and a plural sentence model) were made available to the subject but imitation of only one model was reinforced during any one condition. Results indicated the subject labelled probe (generalization) items with the same sentence form that was modelled and reinforced during training trials.

Journal Article↗