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Biomedical subjects

P Chase

Publications and source records attributed to P Chase.

At least 19 recordsLinked to original sources
PubMed1997

Collection and recruitment of CD34+ cells during large-volume leukapheresis.

Although sufficient progenitor cells for hematopoietic rescue following high-dose therapy may be obtained in a single leukapheresis, the majority of patients require multiple procedures. In an attempt to minimize the number of leukapheresis and maximize collection efficiency, we undertook large-volume leukapheresis in 17 patients with a variety of hematologic malignancies. Twenty-four procedures were performed over a 6-h period, with a mean of 21 L of blood processed. By employing a modified collection set, three separate 2-h collection bags were analyzed for a number of variables. CD34+ cells are collected at a steady rate throughout the procedure, with no evidence of exhaustion of progenitor cells. There was evidence of progenitor cell recruitment, with 1.4-fold more CD34+ cells in the collected product than were present in the blood at the beginning of the procedure. Initiation of leukapheresis was based on the blood CD34+ count, and this value was strongly correlated with the number of CD34+ cells in the collected product. The procedure is safe and relatively simple and minimizes the number of leukaphereses required to collect adequate progenitors for autologous transplantation.

Adolescent↗
PubMed1996

Antiislet autoantibodies usually develop sequentially rather than simultaneously.

The goal of this study was to address whether antiislet autoantibodies appear sequentially or simultaneously before the onset of type I diabetes. We analyzed sequential serum samples from 155 siblings and offspring (aged < 7 yr) of patients with type I diabetes from the Denver Diabetes Autoimmunity Study in the Young study and from a separate group of first degree relatives (aged 2-40 yr) for autoantibodies reacting with three defined autoantigens: glutamic acid decarboxylase (GAD65), insulin, and ICA512/IA-2. The youngest age at which 1 of the 3 autoantibodies appeared was 1.1 yr, and the oldest was 60.9 yr. Of the total 26 autoantibody conversion events observed, in only 3 instances did more than 1 autoantibody appear simultaneously. Among individuals (n = 12) with sequential conversion to expression of multiple autoantibodies, anti-GAD65 autoantibodies or antiinsulin autoantibodies appeared first (4 expressed antiinsulin autoantibodies first, and 8 anti-GAD65 autoantibodies first). We conclude that antiislet autoantibodies usually appear sequentially and not simultaneously. This corroborates early suggestions that humoral autoimmunity to islets develops chronically in a process usually measured in months to years. As expression of multiple autoantibodies is associated with a high risk of progression to diabetes, and sequential appearance of autoantibodies can occur late in life, long term follow-up is necessary to fully delineate the relationship of diabetes risk to autoantibody expression.

Adolescent↗
PubMed1995

Rumor management in nursing systems: role of the psychiatric CNS.

RUMOR MANAGEMENT AND control is particularly important in nursing systems during times of change. In this article, a brief history of the study of rumor and the rumor process is given and applied to nursing, systems thinking and the CNS, and three types of rumor are described. Examples are given and strategies and approaches for managing rumor are prescribed. The first approach, used when a final decision about a planned change has not been made, helps avoid "trickle down" and builds trust and empowerment by soliciting and using input from those who will be affected by the proposed change. The intent of the second approach, used when a decision has been finalized or an event has occurred and rumor has preceded an official announcement, is to debrief from the occurrence or transform the decision. The last approach is used to interrupt a pattern of misinformation and to clarify or inform. The nurse leader or manager must stay in the communication loop and refrain from blaming a speculated source in order to correct information.

Communication↗
PubMed1994

Remission and relapse of substance use disorders in schizophrenia. Results from a one-year prospective study.

Recent studies of the effectiveness of specialized programs that treat substance use disorders in schizophrenia have obtained promising results but have not involved control groups. Interpretation of these apparently positive results is problematic because remission and relapse rates of substance use disorders have not been reported in this population. The present study reports 1-year rates of substance abuse and dependence remission and relapse in a sample of schizophrenics taken from the Epidemiologic Catchment Area study. Results indicated that the prevalence of substance use disorders in schizophrenia remained constant over the year primarily because rates of remission were balanced by rates of relapse. Individuals who developed abuse or dependence over the year were younger, male, and showed increases in depression and risk for hospitalization over the year. Individuals who remitted abuse or dependence were older, female, and showed decreases in depression over the year. Dual diagnosis treatment programs have recently reported higher rates of remission than were evidenced in this sample, thus providing preliminary support for the effectiveness of these treatments.

Adult↗
PubMed1991

Influence of IgG1 and IgG2 antibodies to streptococcal group A carbohydrate on neutrophil chemiluminescence.

IgG antibodies to streptococcal group A carbohydrate (A-CHO) were isolated from normal human serum and from pooled Cohn fraction II using N-acetyl-D-glucosamine affinity chromatography columns. They consisted of the subclasses IgG1 and IgG2 in variable proportions depending on the pH of the elution buffer and on the subclass composition of anti-A-CHO in the starting material. Streptococcal group A particles exposing the antigen A-CHO were opsonized with various concentrations of these antibodies and incubated with normal human polymorphonuclear leukocytes (PMN). The luminol-enhanced chemiluminescence (CL) elicited with these particles was recorded over a 60-min period. With 12 of the 14 antibody preparations tested, the observed CL signal was dose-dependent. When used at comparable concentrations for opsonization, the antibodies enriched in IgG1 induced markedly stronger CL signals than those consisting predominantly of IgG2. It was concluded that the observed CL differences reflect mainly the preferential recognition of IgG1 molecules by Fc gamma receptors of PMN.

Antibodies, Anti-Idiotypic↗
PubMed1990

Different mechanisms of increased proteolysis in atrophy induced by denervation or unweighting of rat soleus muscle.

Mechanisms of accelerated proteolysis were compared in denervated and unweighted (by tail-cast suspension) soleus muscles. In vitro and in vivo proteolysis were more rapid and lysosomal latency was lower in denervated than in unweighted muscle. In vitro, lysosomotropic agents (eg, chloroquine, methylamine) did not lessen the increase in proteolysis caused by unweighting, but abolished the difference in proteolysis between denervated and unweighted muscle. Leucine methylester, an indicator of lysosome fragility, lowered latency more in denervated than in unweighted muscle. 3-Methyladenine, which inhibits phagosome formation, increased latency similarly in all muscles tested. Mersalyl, a thiol protease inhibitor, and 8-(diethylamino)octyl-3,4,5-trimethoxybenzoate hydrochloride (TMB-8), which antagonizes sarcoplasmic reticulum release of Ca2+, reduced accelerated proteolysis caused by unweighting without diminishing the faster proteolysis due to denervation. Calcium ionophore (A23187) increased proteolysis more so in unweighted than control muscles whether or not Ca2+ was present. Different mechanisms of accelerated proteolysis were studied further by treating muscles in vivo for 24 hours with chloroquine or mersalyl. Chloroquine diminished atrophy of the denervated but not the unweighted muscle, whereas mersalyl prevented atrophy of the unweighted but not of the denervated muscle, both by inhibiting in vivo proteolysis. These results suggest that (1) atrophy of denervated, but not of unweighted, soleus muscle involves increased lysosomal proteolysis, possibly caused by greater permeability of the lysosome, and (2) cytosolic proteolysis is important in unweighting atrophy, involving some role of Ca2(+)-dependent proteolysis and/or thiol proteases.

Animals↗
PubMed1989

Neutrophil chemiluminescence induced by opsonized group A streptococcal particles: an effective probe of intravenous immunoglobulin preparations.

We compared the capacity of eight different intravenous immunoglobulin (IVIG) preparations to opsonize streptococcal group A particles and to induce luminol-enhanced chemiluminescence in neutrophil granulocytes. Antibodies to the streptococcal group A carbohydrate (A-CHO) antigen exposed on the particles were present in all preparations at high concentrations. In some preparations, anti-A-CHO consisted predominantly of either immunoglobulin G1 (IgG1) or IgG2, whereas in others, both IgG subclasses were equally represented. Dilutions of the IVIGs and of a normal IgG reference preparation were adjusted for their anti-A-CHO content, incubated with streptococcal particles, and exposed to neutrophil granulocytes isolated from normal blood. The various IVIGs differed in their capacity to elicit chemiluminescence signals. Some preparations, particularly those consisting of chemically modified IgG molecules, showed little activity, whereas others were comparable to the reference preparation. We concluded that to some extent such differences could be related to the IgG subclass composition of the antibody. However, of greater importance were the manufacturing procedures by which both the antigen-binding fragment and crystallizable fragment portions, and thus the functional integrity of the IgG molecules, were more or less severely affected.

Humans↗
PubMed1987

Pneumonia in pediatric outpatients: cause and clinical manifestations.

The cause and clinical manifestations of pneumonia were studied in 98 pediatric outpatients. A viral diagnosis was established in 38 (39%) of the 98 patients, and a bacterial diagnosis in 19 (19%). Ten (53%) of the 19 patients with bacterial pneumonia had a concurrent viral infection. No clinical, laboratory, or radiographic findings that would reliably differentiate viral from bacterial infection were identified. This study suggests that bacterial pneumonia is more common in pediatric outpatients than previously reported, and that the clinical, laboratory, and radiographic findings in patients with bacterial infection may be indistinguishable from findings in patients with viral infection.

Adolescent↗
PubMed1979

Defective cellular immunity to gram-negative bacteria in cystic fibrosis patients.

In vitro lymphocyte responses to Pseudomonas aeruginosa have been found to be impaired in cystic fibrosis patients with advanced clinical disease. The responses to Klebsiella pneumoniae, Serratia marcescens, and Proteus mirabilis were studied in a similar group of cystic fibrosis patients and normal individuals. Cystic fibrosis patients found to be unresponsive to pseudomonas were also unresponsive to klebsiella, serratia, and proteus. Responsiveness to Staphylococcus aureus was not impaired in cystic fibrosis patients. We postulate that in vitro lymphocyte responses to several gram-negative bacteria require the function of a lymphocyte subpopulation which may be impaired in some cystic fibrosis patients.

Antigens, Bacterial↗