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Biomedical subjects

E Lee

Publications and source records attributed to E Lee.

At least 379 records · Page 21Linked to original sources
PubMed1988

Quantification of colonic lamina propria cells by means of a morphometric point-counting method.

The lamina propria of colonic mucosa normally contains eosinophils, lymphocytes, plasma cells, and a few neutrophils. If the number of such cells is judged to be increased, colonic inflammation is said to be present. However, the number of cells present in normal mucosa has not been clearly established. Mild abnormalities are difficult to identify, yet might be associated with colonic dysfunction. We therefore developed a morphometric point-counting method to quantitatively analyze the areas occupied by different structures in the mucosa of the human colon. A computer was used to move a dot in a rectilinear pattern over the X400 magnified image of biopsy specimens obtained from throughout the colon by colonoscopy. The structure on which the dot landed was identified and tabulated by a pathologist. In preliminary studies, we established counting parameters that would yield the most representative results. Based on statistical analysis, it was decided to count 98 points in each of seven regions of six biopsy specimens, i.e., over 4000 points per subject. Results were expressed as percentages of counts landing on a given item, and represented the area of the biopsy specimen covered by that item. Using this method, we determined the range of normal in healthy volunteers. The sensitivity of this method was tested by studying patients with chronic diarrhea previously diagnosed as having or not having mild to moderate mucosal inflammation. In the patient group, colonic fluid absorption measured by a perfusion technique was directly correlated with epithelial cell counts and inversely correlated with lamina propria cellularity and with the counts of lamina propria neutrophils and plasma cells. We conclude that morphometric analysis of colon biopsy specimens can be used to quantitate histologic features of colonic mucosa and to accurately identify even mild abnormalities, and that it can be a useful clinical research tool.

Adult↗
PubMed1988

Influence of ozone stress on growth processes, yields and grain quality characteristics among soybean cultivars.

Field studies were conducted at USDA Beltsville Agricultural Research Center, Beltsville, Maryland, in 1984 and 1985 using open-top chambers to acquire information on the responses of 12 soybean (Glycine max L. Merr.) cultivars to O3 stress and to examine the interactions between maturity groups and O3 stress. Cultivars representing Groups III, IV, and V were exposed for approximately 3 months to charcoal-filtered air (CF) and nonfiltered air plus 40 nl litre(-1) O3 (NF + O3). Ozone was added 6 h d(-1), 5 d week(-1) for 13 weeks. The CF effectively reduced the accumulative oxidant exposure (AOX) to less than 1.0 microl litre(-1) h and the NF + O3 treatment approximately doubled the ambient AOX (16.7 microl litre(-1) h) to about 30 microl litre(-1) h. The AOX estimates the total O3 exposure above 30 nl litre(-1) during an entire growing season. Plant growth rates and relative growth rates were reduced by 17.0 and 14.4%, respectively, when averaged over cultivars. Based on growth rates, the Group III cultivars were the most affected by O3 stress. Averaged over cultivars, leaf expansion rates, leaf conductance, and transpiration rates were lower in the NF + O3 treatment compared to the CF control; however, wide variation was found with the stomatal results from field observations. Combined over years and cultivars, grain yield was reduced by an average of 12.5% by O3 stress with 3 of 12 cultivars showing significant reductions. Grain protein content was increased by 0.7% by O3 stress, but cultivar differences were equal to the differences caused by the O3 treatments. Grain oil content was unchanged by the O3 treatments. Group IV cultivars showed the greatest decrease in grain yield due to O3 stress. Multiple regression analyses were calculated using the difference between the CF and NF + O3 treatment as a measure of O3 stress. Significant positive relationships were found among net assimilation rates, plant growth rates, relative growth rates, and leaf expansion rates, which suggest that growth analysis characteristics would be useful in addition to yield in air pollution tolerance improvement studies with soybeans.

Journal Article↗
PubMed1988

Immunologic outcome of enteric administration of ovalbumin to neonatal rats is anatomic-site specific.

An important immunologic response to the oral ingestion of a protein antigen is systemic tolerance to subsequent parenteral encounter with the same antigen. In the newborn intestine, ileal epithelial cells nonspecifically take up macromolecules and degrade them in lysosomal enzyme-containing vacuoles. We speculated that processing of protein antigens by the ileal cells helps mediate systemic immunologic tolerance to the antigens. Therefore, we developed a neonatal rat model in which ovalbumin (OVA) was administered either by gastric gavage or by infusion into surgically constructed loops of jejunum or ileum. We also administered OVA to other groups of animals by injection into the intact jejunum or ileum. Two and 4 weeks later, animals were challenged with OVA measured. Whereas animals that received OVA by gastric gavage were made tolerant to the protein (produced no detectable serum IgG anti-OVA antibodies after parenteral challenge), the animals given OVA into the jejunum or ileum did not show tolerance; indeed, some of those given OVA into the ileum were immunized by the enteric exposure. From these data we postulate that the development of systemic immunologic tolerance to a protein antigen in the newborn requires "upstream" processing of the antigen by gastric or pancreatic secretions and that exposure of the distal intestine to intact protein antigens can result in systemic sensitization to the antigens. The latter response might be causally linked to food allergies or autoimmune diseases.

Animals↗
PubMed1988

Cultural factors in working with Southeast Asian refugee adolescents.

The purpose of this paper is to present some of the unique socio-political-cultural factors that impact upon the psychological development of Southeast Asian refugee adolescents. As a special group of youngsters, they are confronted with the developmental crisis as adolescents, adjustment problems as refugees, and intercultural conflicts caused by the immense value differences between Eastern and Western cultures. In working with this population, clinicians are urged to take into account the special stressors resulting from the refugee and cultural experiences. Three areas of assessment are recommended: (1) assessment of major stresses (migration stress, acculturation stress, life cycle stress, and family stress); (2) assessment of strengths; and (3) assessment of culturally specific responses to mental health problems. Different treatment modalities are also discussed. It is hoped that the practical suggestions presented in this paper can lead to more culturally relevant care for this group of youths.

Acculturation↗
PubMed1988

A milk protein gene promoter directs the expression of human tissue plasminogen activator cDNA to the mammary gland in transgenic mice.

Whey acidic protein (WAP) is a major whey protein in mouse milk. Its gene is expressed in the lactating mammary gland and is inducible by steroid and peptide hormones. A series of transgenic mice containing a hybrid gene in which human tissue plasminogen activator (tPA) cDNA is under the control of the murine WAP gene promoter had previously been generated. In this study, 21 tissues from lactating and virgin transgenic female mice containing the WAP-tPA hybrid gene were screened for the distribution of murine WAP and human tPA transcripts. Like the endogenous WAP RNA, WAP-tPA RNA was expressed predominantly in mammary gland tissue and appeared to be inducible by lactation. Whereas WAP transcripts were not detected in 22 tissues of virgin mice, low levels of WAP-tPA RNA, which were not modulated during lactation, were found in tongue, kidney, and sublingual gland. These studies demonstrate that the WAP gene promoter can target the expression of a transgene to the mammary gland and that this expression is inducible during lactation.

Animals↗
PubMed1988

Effect of immunization with prostaglandin metabolites on gastrointestinal ulceration.

Active immunization of rabbits with a 6-ketoprostaglandin F1 alpha-thyroglobulin conjugate induced gastrointestinal ulceration, whereas active immunization of rabbits with 13,14-dihydro-15-keto prostaglandin E2-thyroglobulin conjugate or with thyroglobulin alone did not result in ulceration. Passive immunization of a separate group of rabbits with 6-ketoprostaglandin F1 alpha-hyperimmune plasma, obtained from actively 6-ketoprostaglandin F1 alpha-immunized donor rabbits that had ulcers, induced gastric ulceration within 9 days, whereas passive immunization of rabbits with control plasma, obtained from donor rabbits actively immunized with thyroglobulin alone, did not induce ulceration. Ulcerogenic donor plasma containing antibody to 6-ketoprostaglandin F1 alpha neutralized the inhibitory actions of prostacyclin on adenosine diphosphate-induced platelet aggregation, indicating that this antibody cross-reacted with prostacyclin. In contrast, plasma containing antibodies to 13,14-dihydro-15-ketoprostaglandin E2 cross-reacted only slightly with prostaglandin E2. Thus antibodies to inactive metabolites of prostaglandins induce ulceration only if these antibodies cross-react with an endogenous, "cytoprotective" prostaglandin.

6-Ketoprostaglandin F1 alpha↗
PubMed1988

Oxidative metabolism of propylthiouracil by peroxidases from rat bone marrow.

1. Propylthiouracil (PTU) was degraded by myeloperoxidase (MPO) or eosinophil peroxidase (EPO), purified from rat bone marrow, in the presence of H2O2 and Cl-. In the absence of either H2O2 or Cl-, MPO and EPO do not degrade PTU. Optimum concentrations of KCl for MPO and EPO were 50 and 250 mM, respectively. 2. The characteristics of PTU degradation by MPO-H2O2-Cl- were similar to those of the chlorinating activity of the peroxidase. 3. Hypochlorous acid as well as MPO-H2O2-Cl- also degraded PTU. Metabolites of PTU degradation by MPO-H2O2-Cl-, which were separated by C18 reversed phase h.p.l.c., were the same as those produced by hypochlorous acid. 4. Of the metabolites of PTU formed by MPO-H2O2-Cl-, one was identified as PTU sulphonic acid (6-propyl-4-hydroxypyrimidine-2-sulphonate) and another seemed to be propyluracil.

Animals↗
PubMed1988

Treatment of the seronegative spondyloarthropathies with sulfasalazine.

Three patients with reactive arthritis and 2 with ankylosing spondylitis resistant to therapy with nonsteroidal antiinflammatory drugs were treated with enteric coated sulfasalazine in an open trial. Significant toxicity was not observed; 1 patient discontinued sulfasalazine because of gastrointestinal symptoms. As a group, statistically significant improvement was observed in 50 foot walk time, morning stiffness, and hemoglobin concentration. One patient went into complete clinical remission, 2 improved, 1 showed no change, and 1 worsened. Asymptomatic colonic inflammation was found in each of 4 patients examined before beginning therapy. Changes in bowel pathology did not parallel changes in joint symptoms. Sulfasalazine may be a safe and useful therapeutic modality in patients with chronic reactive arthritis or ankylosing spondylitis.

Adolescent↗
PubMed1988

Pregnancy in women with diffuse mesangial proliferative glomerulonephritis.

The clinical course of 168 pregnancies in 91 women with non-IgA diffuse mesangial proliferative glomerulonephritis has been analyzed. Twenty percent (33) of pregnancies resulted in fetal loss, 18% (31) in premature delivery and 62% (105) in a term infant. Maternal renal function declined, reversibly, in 3% (5) of pregnancies and in 48% (80) hypertension developed. In 53% (89) a significant increase in proteinuria occurred in pregnancy. Fetal and maternal complications of pregnancy occurred more frequently in patients with pre-existing hypertension although differences failed to reach statistical significance (p greater than 0.01). The presence of severe vessel lesions on the diagnostic renal biopsy was associated with a significantly higher fetal loss and prematurity rate (p less than 0.0005 and p less than 0.005, respectively).

Female↗
PubMed1988

Development of a second clonally discrete Burkitt's lymphoma in a human immunodeficiency virus-positive homosexual patient.

We have studied, at a molecular level, two small non-cleaved cell malignant lymphomas (Burkitt's type) that were separated by a disease-free interval of 3 years in a patient infected with the human immunodeficiency virus (HIV). The late occurrence of the apparent relapse suggested that the second lymphoma might be caused by a separate malignant transformation in a discrete clone of B cells. Although both tumors expressed the same immunologic surface markers (mu k) and carried the same t(8;14) translocation, Southern blot analysis of DNA from each tumor, using specific restriction endonucleases and probes to the c-myc and the immunoglobulin heavy chain loci, demonstrated that the chromosomal breakpoints relevant to the translocations differed between the tumors. This was corroborated by analysis of the immunoglobulin light-chain rearrangements in the two tumors. These observations indicate that the second tumor was not a recurrence of the first but represented the malignant transformation of a different clone of B cells. Thus late relapses of certain malignancies in individuals at high risk may be caused by the malignant transformation of discrete cell clones (i.e., induction of a new tumor).

Acquired Immunodeficiency Syndrome↗
PubMed1987

Tissue factor apoprotein: intracellular transport and expression in shed membrane vesicles.

We have studied the synthesis and subcellular distribution of the glycosylated membrane protein tissue factor (TF) in human blood monocytes and the inducible monocyte like cell line, HL-60. Following induction with endotoxin or the phorbol ester, TPA, tissue factor specific activity was measured in intact cells, sonicated cells, isolated plasma membranes and shed vesicles. We have shown that TF is transported over time from the cytoplasm to the plasma membrane and finally to shed membrane vesicles. Optimal transport of TF to the plasma membrane and shedding in membrane vesicles required glycosylation as judged by partial inhibition of this process by the tunicamycin homologues B2 and C2.

Apoproteins↗
PubMed1987

Conserved elements in the 3' untranslated region of flavivirus RNAs and potential cyclization sequences.

We have isolated a cDNA clone after reverse transcription of the genomic RNA of Asibi yellow fever virus whose structure suggests it was formed by self-priming from a 3'-terminal hairpin of 87 nucleotides in the genomic RNA. We have also isolated a clone from cDNA made to Murray Valley encephalitis virus RNA that also appears to have arisen by self-priming from a 3'-terminal structure very similar or identical to that of yellow fever. In addition, 3'-terminal sequencing of the S1 strain of dengue 2 RNA shows that this RNA is also capable of forming a 3'-terminal hairpin of 79 nucleotides. Furthermore, we have identified two 20-nucleotide sequence elements which are present in the 3' untranslated region of all three viruses; one of these sequence elements is repeated in Murray Valley encephalitis and dengue 2 RNA but not in yellow fever RNA. In all three viruses, which represent the three major serological subgroups of the mosquito-borne flaviviruses, the 3'-proximal conserved sequence element, which is found immediately adjacent to the potential 3'-terminal hairpin, is complementary to another conserved domain near the 5' end of the viral RNAs, suggesting that flavivirus RNAs can cyclize (calculated delta G less than -11 kcal; 1 kcal = 4.184 kJ).

Base Sequence↗
PubMed1987

Polyclonal polymorphic B-cell lymphoproliferative disorder with prominent pulmonary involvement in children with acquired immune deficiency syndrome.

Four cases of pediatric Acquired Immune Deficiency Syndrome (AIDS) with lymphoproliferative disorder are described and other lymphoid lesions in previously reported cases of pediatric AIDS are reviewed. The lymphoproliferative disorder was characterized by polyclonal, polymorphic B-cell content without evidence of cellular atypia, necrosis or prominent mitotic activity but with predominantly extranodal systemic and prominent pulmonary involvement. Since the lesion has overlapping features it is considered to be intermediate between benign and malignant lymphoproliferations and designated as polyclonal, polymorphic B-cell lymphoproliferative disorder (PBLD) of pediatric AIDS. The PBLD is part of a spectrum of lymphoid lesions in pediatric AIDS consisting of follicular lymphoid hyperplasia of nodal and extranodal sites, pulmonary lymphoid hyperplasia/lymphoid interstitial pneumonitis complex (PLH/LIP complex) in cases previously reported by the authors, and also malignant lymphoma reported by others. It is possible that Epstein-Barr virus (EBV) by itself or in synergism with human T-lymphotropic virus-type III (HTLV-III) is related to pathogenesis of PBLD in children with AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1987

Sex-related difference of kinin level in rat pituitary gland.

The kinin level in the pituitary glands was compared in adult male and female rats. A sex-related difference in the bradykinin (BK)-like immunoreactivity was found in the posterior lobe. The posterior pituitaries of female rats contained a higher concentration of the immunoreactive kinin than those of males. Ovariectomy of female rats resulted in the disappearance of a sex difference in the posterior kinin level and about a 3-fold increase in the anterior one. Orchidectomy of adult male rats failed to alter the kinin levels in both lobes. Moreover, the constitution of pituitary kinins was determined using HPLC. The pituitary kinins consisted of BK, Lys-BK (L-BK) and Met-Lys-BK (ML-BK) in different proportions in both lobes of male and female rats. The gonadectomy altered the proportions of these kinins. These results suggest that the pituitary kinin system may be regulated by circulating gonadal steroid hormones.

Animals↗
PubMed1987

Purification and some properties of peroxidases of rat bone marrow.

Myeloperoxidase and eosinophil peroxidase were separated and purified from rat bone marrow cells using cetyltrimethylammonium bromide as the solubilizer and then with column chromatographies on CM-Sephadex C-50 and Con A-Sepharose. Both purified enzymes were observed to be apparently homogeneous by SDS-polyacrylamide gel electrophoresis. Myeloperoxidase consisted of two subunits of Mr 57,000 and 15,000, and eosinophil peroxidase two of 53,000 and 14,000. On structural analysis of the enzymes, their visual and ESR spectra revealed that the structure surrounding the heme in myeloperoxidase was different from that in eosinophil peroxidase. Moreover, substrate specificity and sensitivity to inhibitors such as azide and cyanide differed between the two enzymes. Rat bone marrow possesses two distinct peroxidases, myeloperoxidase and eosinophil peroxidase, which have different subunits and different heme microenvironments. Therefore, the difference in enzymatic function between the two peroxidases may be due to their structures.

Animals↗