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Biomedical subjects

K Barron

Publications and source records attributed to K Barron.

15 recordsLinked to original sources
PubMed2005

EULAR/PReS endorsed consensus criteria for the classification of childhood vasculitides.

BACKGROUND: There has been a lack of appropriate classification criteria for vasculitis in children. OBJECTIVE: To develop a widely accepted general classification for the vasculitides observed in children and specific and realistic classification criteria for common childhood vasculitides (Henoch-Schönlein purpura (HSP), Kawasaki disease (KD), childhood polyarteritis nodosa (PAN), Wegener's granulomatosis (WG), and Takayasu arteritis (TA)). METHODS: The project was divided into two phases: (1) the Delphi technique was used to gather opinions from a wide spectrum of paediatric rheumatologists and nephrologists; (2) a consensus conference using nominal group technique was held. Ten international experts, all paediatricians, met for the consensus conference. Agreement of at least 80% of the participants was defined as consensus. RESULTS: Consensus was reached to base the general working classification for childhood vasculitides on vessel size. The small vessel disease was further subcategorised into "granulomatous" and "non-granulomatous." Final criteria were developed to classify a child as HSP, KD, childhood PAN, WG, or TA, with changes introduced based on paediatric experience. Mandatory criteria were suggested for all diseases except WG. CONCLUSIONS: It is hoped that the suggested criteria will be widely accepted around the world because of the reliable techniques used and the international and multispecialist composition of the expert group involved.

Child↗
PubMed1994

An educational needs assessment of children with juvenile rheumatoid arthritis.

OBJECTIVE: Our objective is to describe the use of the PRECEDE model (predisposing, reinforcing, and enabling causes in educational diagnosis and evaluation) to organize needs assessment data in order to define self-management behaviors and plan an educational intervention for children with juvenile rheumatoid arthritis (JRA) and their families. METHODS: Analysis was done of needs assessment data collected from several sources: 1) literature review, 2) survey of parents of 51 children with JRA, 3) group interview of seven parents of children with JRA, 4) results of pilot programs, and 5) clinical experience of an interdisciplinary pediatric rheumatology team. RESULTS: Two sets of interrelated behavioral factors were identified through the needs assessment: 1) those related to managing the school environment to facilitate optimal participation and to minimize school-related disability, and 2) those related to treating pain and stiffness, intervening in the disease process, and preserving joint function. CONCLUSION: Both of these sets of behavioral factors may be related to the optimization of children's mobility, joint function, and autonomy of activities of daily living and should be targets of an educational intervention.

Adolescent↗
PubMed1993

Governmental policy and personal experiences. The development towards integration of mobility disabled students into regular schools in Scandinavia.

The Scandinavian countries have been among the leading countries with regard to integration into society for persons with disabilities. This article focuses on two intimately related questions concerning the reform: 1) How did the normalization principle, as governmental policy, intend to improve the living-situation for people with disabilities? 2) How was the reform experienced by some disabled persons who attended compulsory school during its introduction? Our sources are: a) central government documents and reports concerning integration of mobility disabled persons in Norway and Sweden; b) 40 life history interviews with mobility disabled persons in Scandinavia born between 1955 and 1965. The interviews are theme centered upon experiences in education and work.

Adolescent↗
PubMed1988

Abnormalities of immunoregulation in Kawasaki syndrome.

The object of our investigation was to determine the immunoregulatory abnormalities in 48 children with Kawasaki syndrome. We demonstrated a global lymphocytosis with marked expansion of the B cell subset. Despite an increase in B cell numbers, there was a decrease in in vitro immunoglobulin production in response to pokeweed mitogen and hydrocortisone stimulation. These abnormalities correlated with a marked increase in the percentage of CD4+2H4+ (CD4+CD45R+) T cells, a T cell subset thought to be responsible for inducing suppression. Other abnormalities of T cells include cutaneous and in vitro anergy and evidence of T cell activation. Our results suggest that the B cell abnormalities seen in Kawasaki syndrome may be partially explained by defects in T cell immunoregulation.

Antigens, Differentiation↗
PubMed1978

Identification of hydrallazine and hydrallazine hydrazone metabolites in human body fluids and quantitative in vitro comparisons of their smooth muscle relaxant activity.

1 Serum and urine from hypertensive subjects on chronic oral hydrallazine therapy were studied using gas chromatographic/mass spectrometry techniques. 2 Metabolites resulting from acetylation, hydrolysis and conjugation reactions were detected. The acetone, pyruvate and alpha-ketoglutarate hydrazone were identified. 3 The activity of the pyruvate and alpha-ketoglutarate hydrazones were compared with that of hydrallazine using isolated rabbit aortic strips. 4 Both hydrazones were active under in vitro conditions, producing smooth muscle relaxant effects equal to those of hydrallazine. 5 It is concluded that hydrazone metabolites will contribute to the hypotensive effects of hydrallazine therapy in proportion to their relative abundance, persistence in vascular tissues and intrinsic activity.

Animals↗
PubMed1978

Interaction of hydralazine and hydrazone derivatives with contractile mechanisms in rabbit aortic smooth muscle.

The mechanism of action and relative potency of hydralazine (H) and tow hydrazone derivatives were investigated using isolated rabbit aortic strips. H, hydralazine acetone hydrazone (HA) and hydralazine butanone hydrazone (HBH) relaxed established K+ and norepinephrine (NE) contractures, and inhibited the development of contractures to these two agents on preincubation. H, HA and HBH increased the threshold to Ca++ and decreased the maximum tension responses during K+-Ca++-contractures (HA greater than H, P less than .05; HBH greater than H P less than .01). The Ca++-dependent and Ca++-independent components of NE contractures were both inhibited by H, HA and HBH. NE contractures were more sensitive to the effects of H than K+ contractures. These results are consistent with the conclusion that H and hydrazone derivatives produce effects on vascular muscle both by interactions with the fluxes of Ca++ from the extracellular space and effects on release from cell stores. However, other possibilities need to be assessed experimentally.

Animals↗
PubMed1978

Study of in vitro effects of hydralazine metabolites--comparative evaluation of products of hydroxylation, hydrolysis and conjugation.

K+ contractures were induced in paired strips of rabbit aortic smooth muscle. The relationship between relaxant effects and the bath concentration of hydralazine acetone hydrazone (HA), 4-OH-hydralazine (HH) and phthalazine (P) was studied over the concentration range 10(-5)-10(-3)M. All compounds were active, HA = HH greater than P (p less than 0.05; n = 6) at concentrations in the range 10(-4)-10(-3M, HA greater than HH at a concentration of 10(-3M (pgreater than 0.01). The activity of HA did not depend on significant reconversion to hydralazine (H) in the bath ( less than 0.5%). A range of H derivatives may contribute to the hypotensive effects of administered H.

Animals↗
PubMed1977

Comparative evaluation of the in vitro effects of hydralazine and hydralazine acetonide on arterial smooth muscle.

1. Dose-response relationships to K+ were determined in isolated strips of rabbit aorta. 2. K+ contractures were induced by 30 mM K+ in paired strips from individual animals. The effects of hydralazine and hydralazine acetone hydrazone (hydralazine acetonide) on these contractures were studied. 3. Hydralazine and hydralazine acetonide both produced dose-dependent decreases of K+-induced tone. Threshold concentrations for hydralazine were 11.89 +/- 4.5 X 10(-5) M (mean +/- s.d.) and for hydralazine actonide 9.7 +/- 4.6 X 10(-5) M (0.5 less than P less than 0.4). 4. The magnitude of the effect of hydralazine acetonide was greater than that of hydralazine at all concentrations above threshold, as reflected in a significant difference (P less than 0.05) in the slopes of dose-response curves to the two treatments. The vasodilator effects of hydralazine and the acetonide were terminated by washout of the bath. 5. The differences in effect were not due to instability of hydralazine under in vitro conditions. 6. It is concluded that hydralazine acetonide has intrinsic activity on vascular smooth muscle which differs significantly from that of the parent compound and that this may contribute to the hypotensive effects which follow administration of the parent compound.

Animals↗
PubMed1975

Waldenström's macroglobulinemia and neuropathy. Deposition of M-component on myelin sheaths.

Chronic idiopathic polyneuropathy of a primary demyelinating type developed in a man who had had recurrent herpes simplex 2 for 10 years. A serum IgM kappa M-component was demonstrated on the myelin of individual sural nerve fibers by direct immunofluorescence microscopy. Marrow lymphocytosis and serum M-component increased with time. Attempts to confirm antibody activity of the M-component were negative. The evidence suggests that the attachment of M-component to nerve is a physical-chemical one. Interaction of M-component and nerve appears to have led to the neuropathy as an early manifestation of Waldenström's macroglobulinemia.

Antibodies, Viral↗
PubMedDate not supplied

Two possible actions for circulating angiotensin II in the control of vasopressin release.

The supraoptic-hypophyseal tract is a primary system for the synthesis and release of vasopressin. Angiotensin II (AII) has been shown to release vasopressin when injected into the cerebral ventricles (IVT). However, intravenous (IV) AII injections have not produced consistent results. The present studies were conducted to examine the effects of AII delivered by either route on the unit activity of supraoptic nucleus (SON) magnocellular neurons. Rats were prepared with intracranial cannulas to insure delivery of drugs to the left lateral ventricle and with polyethylene catheters in the left jugular vein, femoral vein, and femoral artery for systemic injections and arterial pressure recordings. A ventral approach permitted recording from the SON without violating the ventricular-SON partition. Magnocellular neurons were electrophysiologically identified. In the majority of identified cells, IVT AII increased activity. In others pressor doses of AII IV inhibited firing while blood pressure was elevated. After sino-aortic denervation, AII IV excited SON neurons. Based on latency, and the fact that lesioning the anteroventral third ventricle blocked the action of AII IVT, the results indicate that AII IVT acts on a periventricular site to influence SON magnocellular neurons. Furthermore, systemic AII may have two effects on SON neurons: a central excitatory action, and an inhibition due to a baroreceptor reflex.

Angiotensin II↗
PubMedDate not supplied

A COMIT model utilization to improve first-case start time.

The purpose of this article is to review the problems and processes impacting the deviation in first-case actual start times when compared to first-case scheduled start times. This article will also discuss the Continuous Outcomes Measurement and Improvement Technique (COMIT) model for problem resolution and share the experiences encountered by a group of collaborative nurse manager leaders in their outcome improvement efforts. The overall process improvements are discussed using the eight-step COMIT model, which showed the overall success of the project.

Analysis of Variance↗