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Biomedical subjects

A M Reed

Publications and source records attributed to A M Reed.

36 records · Page 2Linked to original sources
PubMed1995

FDDI information management system for centralizing interactive, computerized multimedia clinical experiences in pediatric rheumatology/Immunology.

This paper describes the design, authoring, and development of interactive, computerized, multimedia clinical simulations in pediatric rheumatology/immunology and related musculoskeletal diseases, the development and implementation of a high speed information management system for their centralized storage and distribution, and analytical methods for evaluating the total system's educational impact on medical students and pediatric residents. An FDDI fiber optic network with client/server/host architecture is the core. The server houses digitized audio, still-image video clips and text files. A host station houses the DB2/2 database containing case-associated labels and information. Cases can be accessed from any workstation via a customized interface in AVA/2 written specifically for this application. OS/2 Presentation Manager controls, written in C, are incorporated into the interface. This interface allows SQL searches and retrievals of cases and case materials. In addition to providing user-directed clinical experiences, this centralized information management system provides designated faculty with the ability to add audio notes and visual pointers to image files. Users may browse through case materials, mark selected ones and download them for utilization in lectures or for editing and converting into 35mm slides.

Allergy and Immunology↗
PubMed1993

Repair of osteopenia in children with juvenile rheumatoid arthritis.

To test the hypothesis that the presence of osteopenia in juvenile rheumatoid arthritis is directly correlated with clinical disease activity and therefore reversible, we prospectively studied cortical bone mineral density (BMD) serially in 27 children. Twenty-four (89%) had BMD > or = 2 SD below age-related normal values (disease duration 49.3 +/- 7.7 months) at the beginning of the study. Of 27 children who had clinical disease improvement measured by a disease activity score during our study period, 17 (63%) had significant improvement or significant normalization, or both, of their BMD (0.34 +/- 0.13 gm/cm2 at initiation and 0.41 +/- 0.17 gm/cm2 at completion, p < 0.05; disease activity score of 3.4 +/- 0.2 at initiation and 1.4 +/- 0.2 at completion, p < 0.005). The increase in BMD was associated with a similar directional change in serum osteocalcin concentrations (4.6 +/- 1 ng/ml at initiation vs 9.1 +/- 1.1 ng/ml). The 10 patients whose disease became or remained active had a decreased or unchanged low serum osteocalcin level and BMD (BMD 0.37 +/- 0.17 gm/cm2 at initiation and 0.37 +/- 0.16 gm/cm2 at completion; disease activity score of 3.1 +/- 0.3 at initiation and 3.4 +/- 0.2 at study completion). We conclude that children with JRA who have improvement in their disease activity have an improvement in BMD heralded by an increase in serum osteocalcin values.

Adolescent↗
PubMed1992

Testing intelligent wound dressings.

While occlusive wound dressings help provide patients with moist wound healing to reduce pain and increase reepithelialization rate, the moisture vapor transmission rate (MVTR) of these dressings remains constant even though wound exudate levels may vary with time and from wound to wound. The clinician is therefore faced with exudate buildup in heavily exuding wounds and desiccation in lightly exuding wounds-a situation requiring frequent patient monitoring and dressing changes. Am "intelligent" wound dressing would have the ability to automatically respond to a wound's exudate level by self-adjusting its MVTR to maintain a constant moist wound environment. Such a dressing could help ensure that exudate buildup or wound desiccation is reduced or avoided. Three commercial wound dressings (hydrocolloid, thin film, and membrane laminate) were studied for their ability to alter their MVTR in response to varying moisture level. An efficient test methodology and experimental design was developed, which involved direct and indirect fluid contact with the dressings using two temperatures and two test methods. One dressing, a membrane laminate, was found to exhibit intelligent MVTR behavior. Data is presented which shows this dressing's ability to adjust its MVTR nearly eight-fold as a function of hydration level. Information regarding the mechanism of action of this intelligent dressing is also presented.

Biocompatible Materials↗
PubMed1992

Biostable polyurethane elastomers.

The generic term polyurethane represents the most versatile family of synthetic polymers. The unsurpassed physical and chemical properties of polyurethanes, coupled with their biocompatibility, have led to their use in a wide range of biomedical applications. Although polyurethanes have been shown to be stable in vitro for many years, they can undergo rapid microcracking when implanted. These microcracks not only weaken the polymer but also serve as nucleation sites for thrombus formation and lead to catastrophic failure. In this article, the authors report on the development and testing of a new ether-free polyurethane that does not exhibit surface microcracking under accelerated in vivo condition.

Animals↗
PubMed1991

Molecular genetic studies of major histocompatibility complex genes in children with juvenile dermatomyositis: increased risk associated with HLA-DQA1 *0501.

Juvenile dermatomyositis (JDMS) is an inflammatory disease associated with HLA-DR3. We therefore undertook molecular genetic studies of HLA region genes to determine whether HLA-DR3 itself confers susceptibility to JDMS or whether susceptibility is conferred by alleles in linkage disequilibrium with HLA-DR3. Our results indicate that JDMS is associated with the HLA-DQA1 allele DQA1 *0501 on non-DR3 haplotypes in Caucasian JDMS. Furthermore, the reported of association between the C4A gene deletion and JDMS is likely due to linkage disequilibrium with HLA-DR3.

Adolescent↗
PubMed1991

In vivo testing of a biostable polyurethane.

At present all the commercially available "medical grade" urethane elastomers exhibit a phenomenon known as environmental stress cracking (ESC). This phenomenon is characterized by surface microcracking when the elastomer is elongated while in vivo. The degree of strain that is required to initiate microcracking varies from composition to composition. It has been found that harder compounds generally tend to have a higher strain threshold than corresponding softer ones. We theorized that this degradation occurs when certain enzymes (present only in vivo) attack and break down the ether linkages that link the polymer molecules together. Those elastomers that contain more ether linkages (such as the softer compositions) appear to microcrack more easily than elastomers with fewer ether linkages (such as the harder ones). The molecular composition of ChronoFlex urethane has been chosen so that the finished elastomer will be free of ether linkages; thus, it is expected to be immune from environmental stress cracking.

Animals↗
PubMed1991

Polyurethanes in medical devices.

Because of their biocompatible qualities, polyurethanes have found many uses in the medical device field. This article describes several of the better-known polyurethanes and discusses their suitability for use in medical applications such as artificial heart systems, catheters, mammary implants, semiocclusive dressings, and drug delivery systems. The adoption and use of these materials by the medical community is likely to increase as new formulations are developed.

Biocompatible Materials↗
PubMedDate not supplied

Chimerism in children with juvenile dermatomyositis.

Juvenile dermatomyositis is a disease with similarities to chronic graft-versus-host disease. To identify whether chimerism is present in juvenile dermatomyositis, we investigated the families of 15 children with the disorder. Chimerism was identified by PCR in 13 of the 15 affected children, compared with five of 35 siblings (p<0.0001). Maternal cells among peripheral-blood mononuclear cells were detected in 11 of the 15 boys, compared with five of 17 unaffected controls (p=0.02), and in muscle tissue of 12 of 15 compared with two of ten unaffected siblings (p=0.005). These results suggest that chimerism may be involved in juvenile dermatomyositis.

Case-Control Studies↗
PubMedDate not supplied

Panniculitis in juvenile dermatomyositis.

Panniculitis is a rarely reported clinical finding in dermatomyositis. We present a 14-year-old African American boy with a 4-year history of dermatomyositis referred for evaluation of tender, indurated plaques and nodules on the trunk and proximal extremities. A biopsy specimen revealed epidermal and dermal changes consistent with dermatomyositis. Although calcification was absent, a striking lobular panniculitis was observed. A total of seven cases of clinical panniculitis in association with dermatomyositis have been published. As in our patient, it typically presents as indurated, tender plaques and nodules on the arms, thighs, and buttocks. Although in the vast majority of cases panniculitis found in association with dermatomyositis is subclinical and represents an incidental histopathologic finding, the case we present further emphasizes the need to recognize panniculitis as a rare, but clinically relevant pathologic feature seen in certain lesions of juvenile dermatomyositis.

Adolescent↗
PubMedDate not supplied

PD-L2+ dendritic cells and PD-1+ CD4+ T cells in schistosomiasis correlate with morbidity.

Dendritic cells (DC) are critical antigen-presenting cells for the induction and control of immune responses. PD-L2 (B7-DC) is a regulatory ligand on subpopulations of DC, and binds to the co-regulatory receptor PD-1, present on some activated T lymphocytes, leading to down-regulation. We now show that very early during experimental schistosomiasis (by 5 weeks) a significantly higher proportion of splenic CD11c+/B220- DC express PD-L2, and by 6 weeks after infection a higher proportion of splenic CD4 T cells express PD-1. In this CBA/J mouse/Schistosoma mansoni chronic infection model we have shown that most mice develop moderate morbidity (Moderate Splenomegaly Syndrome, MSS), while some parallel-infected mice express different immune characteristics and die or develop severe morbidity (Hypersplenomegaly Syndrome, HSS). We now report a positive correlation between the proportion of splenic CD11c+/B220- DC that express PD-L2 and showing MSS. In contrast, there is an inverse correlation between the proportion of splenic CD3+/CD4+ T lymphocytes that express PD-1 and showing MSS. The data demonstrate that schistosomes can induce sustained elevated percentages of PD-L2-expressing, B220-negative DC. Furthermore, when this potentially immunoregulatory environment occurs chronically, infected mice are most likely to have developed MSS, expressing moderate morbidity.

Animals↗