Search PubMed⌕ Search

Biomedical subjects

J Dunne

Publications and source records attributed to J Dunne.

At least 55 records · Page 3Linked to original sources
PubMed1993

Suppression of erythropoiesis by intrauterine transfusions in hemolytic disease of the newborn: use of erythropoietin to treat the late anemia.

Hemolytic disease of the fetus and newborn has three phases of anemia: in utero, in the first week of life, and in the weeks and months after birth. Intrauterine transfusions can ameliorate the severity of both fetal and early anemia, but late anemia and the need for transfusion remain significant problems. Bone marrow hypoplasia--probably a result of suppression of erythropoiesis from the intrauterine transfusions--was documented in the three patients tested in our study. Because erythropoietin (EPO) levels have been found to be low (i.e., normal) in these previously transfused patients despite the degree of anemia, we treated four affected infants with EPO, 200 microliters/kg subcutaneously three times a week, and noted reticulocytosis and increased hemoglobin values 2 to 4 weeks later. One patient again had reticulocytopenic anemia when the EPO therapy was stopped but responded to retreatment. Our study indicates that EPO treatment may be effective in the management of late anemia and could help to decrease the need for postnatal transfusions.

Anemia, Neonatal↗
PubMed1990

Amplified expression of tumor necrosis factor receptor in cells transfected with Epstein-Barr virus shuttle vector cDNA libraries.

As an approach to isolate the cell-surface receptor for tumor necrosis factor (TNF), we have developed transfectants of human B-lymphoblastoid cells (UC cells) that overexpress the TNF receptor. These transfectants were isolated from UC cells transfected with cDNA libraries of HeLa or NG108 cells constructed in the mammalian expression vector EBO-pcD. This vector contains the Epstein-Barr virus origin of replication (ori-P) plus the EBNA-1 gene conferring replication function to ori-P and, therefore, the ability to replicate autonomously within the transfected cell (Margolskee, R.F., Kavathas, P., and Berg, P. (1988) Mol. Cell. Biol. 8, 2837-2947). Cells overexpressing the TNF receptor were identified and separated by the binding of fluoresceinated TNF and flow cytometric selection. Scatchard analysis of 125I-TNF binding data revealed a single class of high affinity receptors with a dissociation constant (Kd) of 0.2 to 2 nM and a receptor density of about 150,000 per cell, an increase of approximately 150-fold over UC cells. Cross-linking of receptor-ligand with bis-sulfosuccinimidyl suberate followed by polyacrylamide gel electrophoresis gave estimates of 87 and 104 kDa for the size of the complex. Based on its ability to bind TNF, a 68-kDa receptor protein was identified in cell extracts enriched for the receptor by using immobilized wheat germ agglutinin and TNF affinity chromatography. The difference in the estimated size of the receptor and the receptor-ligand complexes demonstrates that TNF binds to the receptor as a monomer or a dimer. Analysis of cDNA sequences conferring receptor amplification in transfectants revealed that plasmid DNA was present at 30 or more copies per cell, most likely integrated into the genomic DNA or organized into high molecular weight catenanes, and autonomously replicating units could not be recovered. Therefore, while this vector was useful in generating stable receptor-amplified cells, it was not maintained as a recoverable episome.

Animals↗
PubMed1988

Milk tester's dermatitis.

Hand dermatitis is a frequent problem among workers in milk testing laboratories. An epidemiologic study was conducted at the Pennsylvania Dairy Herd Improvement Association Milk Testing Laboratory, where more than 300,000 milk samples are examined monthly for protein, butterfat, and "somatic" cells. These samples are preserved with potassium dichromate for transport from the farm to the laboratory. A survey of the laboratory was conducted and workers were interviewed. Eight of 16 subjects reported a history of occupationally exacerbated hand dermatitis. Three of 16 subjects had positive patch test results to potassium dichromate. Two of 15 subjects who underwent patch testing to milk preserved with potassium dichromate had positive reactions. None reacted to milk alone, bronopol, or Kathon CG. Two workers are receiving workers' compensation because of severe allergic contact dermatitis of the hands to potassium dichromate. We conclude that milk testing laboratory workers are at substantial risk for acquiring allergic contact dermatitis from milk preserved with potassium dichromate.

Animals↗
PubMed1986

Human papillomavirus types 16 and 18 sequences in early cervical neoplasia.

A total of 100 colposcopic biopsies from patients with abnormal Papanicolau's tests were surveyed for the presence of human papillomavirus (HPV) types 16 and 18 sequences by spot-blot hybridization. HPV 16 and 18 DNA sequences were detected in 58% of the biopsies. None of the cervical intraepithelial neoplasia grade I (CIN I) contained HPV 16 while 50% of the CIN III lesions (carcinoma in situ, CIS) contained HPV 16. HPV 18-related sequences were equally represented in CIN I, II, and III. Southern-blot hybridization of total undigested cellular DNA revealed the presence of HPV DNA sequences only in an episomal form. While the restriction enzyme patterns in HPV 16-positive samples were mostly identical to the originally cloned sequence, the restriction enzyme pattern for HPV 18-positive samples were different from that of HPV 18 but identical to each other. Furthermore, this DNA hybridized more strongly to HPV 18 under nonstringent conditions, suggesting a new type.

Colposcopy↗
PubMed1986

Molecular cloning of the human T-lymphocyte surface CD2 (T11) antigen.

CD2 (T11, sheep erythrocyte receptor) is a surface antigen of the human T-lymphocyte lineage. cDNA clones encoding CD2 have been isolated by using the purified, denatured CD2 to raise a rat antiserum. Positive clones were recognized in a phage lambda gt11 expression library prepared from the human leukemia T-cell line J6. The DNA sequence contained an open reading frame encoding 360 amino acids. The N-terminal 24 amino acids were characteristic of a signal peptide and were followed by a region that matched all 25 residues of the CD2 N terminus previously determined by amino acid sequencing. The predicted amino acid sequence is consistent with that of a transmembrane glycoprotein containing three potential N-glycosylation sites on the N-terminal side of a 26-amino acid hydrophobic segment. There is a large cytoplasmic domain of 125 amino acids that is rich in proline and in basic residues. RNA blot-hybridization analysis demonstrated hybridization only in those T cells that were positive for surface CD2 antigen. There are limited regions of sequence similarity to members of the immunoglobulin supergene family.

Amino Acid Sequence↗
PubMed1985

Immune function in blood donors following short-term lymphocytapheresis.

Lymphocyte losses occur during repeat plateletpheresis and/or leukapheresis procedures and are potentially harmful to normal host immune function. This concern prompted us to study the effect of repeat lymphocytapheresis (lymphapheresis) on the immune system of healthy blood donors. Following a total of six lymphapheresis procedures over a 12-day period with removal of a mean of 41.6 X 10(9) lymphocytes, there were no significant changes in donor (n = 5) absolute lymphocyte counts, quantitative immunoglobulin levels or immune response capability as assessed by the following in vitro assays: percent of E, EA, and EAC rosette-forming cells, the percent of surface membrane immunoglobulin bearing cells, and the blastogenic responses to stimulation with phytohemagglutinin, pokeweed mitogen and concanavalin A. The procedures were well-tolerated without complications. During a follow-up period of 18 months, significant increases in total white cell counts (but not absolute lymphocyte counts), and in quantitative immunoglobulin levels (IgG, IgM, and IgA) were observed. The median increases in immunoglobulin levels ranged from 27.5% for IgG to 44% for IgA. We conclude that lymphapheresis as described is relatively safe and our results are reassuring in relation to lymphocyte losses that may occur during repeat cytapheresis procedures of normal blood donors.

Blood Donors↗