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Biomedical subjects

D R Ownby

Publications and source records attributed to D R Ownby.

66 records · Page 4Linked to original sources
PubMed1984

Attempting to predict hospital admission in acute asthma.

If accurate predictions of outcome could be made, the emergency care of patients with asthma would be expedited. To evaluate how well initial peak flow determinations predicted hospitalization when used alone and when combined with other clinical variables, we prospectively studied 200 visits for the care of acute asthma. Using discriminant analysis, we selected the variables that best predicted discharge or admission for the first 100 cases. The best predictive variables were initial peak flow, history of treatment in preceding 24 hours, age at onset of asthma, and number of previous hospitalizations for asthma. This combination correctly predicted admission or discharge for 82% of the 200 cases. Despite this overall accuracy, admission was not well predicted. In the first 100 cases, only six of the 18 admissions were correctly predicted, and in the second 100 cases, none of the 15 admissions were correctly predicted, Initial peak flow measurements, even when combined with other variables, cannot predict hospitalization well enough to be substituted for a therapeutic trial.

Acute Disease↗
PubMed1984

Development and comparative evaluation of a multiple-antigen RAST as a screening test for inhalant allergy.

We have developed a modified in vitro test for IgE antibodies, the multi-RAST, to detect antibodies of different allergen specificities simultaneously in a single tube. The multi-RAST is as sensitive for detecting low concentrations of individual IgE antibodies as the discrete RAST. We also evaluated the multi-RAST as a screening test for respiratory allergy to inhalant allergens in children by comparing the results of the multi-RAST performed by use of a mixture of SRP, TGP, and DF allergen-immunosorbents with the results of skin tests, discrete RAST tests for the same allergens, serum total IgE concentrations, and nasal smears for eosinophils in 100 children referred for allergic-disease evaluation. The results of the multi-RAST were more sensitive, specific, and efficient than the results of tests for serum IgE concentration and nasal eosinophils in establishing the diagnosis of inhalant allergy; the multi-RAST was the only diagnostic test that yielded results that were significantly associated with the clinician's impression of allergy. We conclude that the multi-RAST is a useful and cost-effective screening test for inhalant allergy in children.

Adolescent↗
PubMed1983

An improved technique for separating rosetted from non-rosetted lymphocytes.

An improved technique for separating rosetted from non-rosetted lymphocytes is described. The major advantage of this new technique is the elimination of the need to mechanically resuspend the cell pellet resulting from the rosette formation step before using a density gradient to separate the rosetted from the non-rosetted cells. Instead the rosette containing cell pellet is directly overlayed with Percoll at a density of 1.078 g/ml and during a subsequent centrifugation the non-rosetted cells float to the surface of the Percoll while the rosetted cells remain in the cell pellet. The utility of this technique is illustrated by separating human T lymphocytes forming rosettes with neuraminidase treated sheep erythrocytes (En) from other mononuclear cells obtained by Ficoll-Hypaque separation of whole blood. Using several markers the resulting T cells were contaminated with less than 0.3% monocytes and 2% B cells. The non-T cell population contained less than 3% T cells. This method offers a rapid and easily reproducible means for obtaining highly purified cell populations.

Antibodies, Monoclonal↗
PubMed1982

Prognostic significance of serum IgE levels in primary breast cancer.

Serum IgE was measured in presurgical sera from 166 nonallergic women admitted to a comprehensive, multidisciplinary study of primary, operable breast cancer. During the follow-up period, which averaged 48 months, there were 71 recurrences. Patients were divided into two groups: those with IgE levels greater than the geometric mean value of 24 I.U. and those with levels less than the mean. The rate of tumor recurrence was significantly greater for the IgE greater than 24 group (p less than 0.03). IgE remained a significant prognostic indicator when evaluated by Cox regression analysis in conjunction with other known prognostic factors including: number of positive lymph nodes, clinical stage, menopausal status, estrogen receptor status, mitotic grade, tumor diameter, breast feeding history, and age of patient (p less than 0.015). IgE was not correlated with any of these known prognostic factors in individual analyses. We conclude that serum IgE level is a significant, independent prognostic indicator in primary breast cancer.

Actuarial Analysis↗
PubMed1982

An improved prick skin-test procedure for young children.

The prick method of skin testing is advantageous for young children because of the decreased risk of anaphylaxis and less patient discomfort. Some would argue, however, that the necessity of keeping extract drops at the skin-test sites makes prick testing impractical compared with intradermal testing for squirming youngsters. Since the literature is not clear concerning the length of time extract must be present at the prick site, we performed duplicate sets of prick tests with five concentrations of ragweed extract on 16 ragweed-sensitive adults. For one set of tests, the drops were removed immediately after the skin had been pricked; for the other set, extracts remained at the site for 15 min. After 15 min we recorded the size of the wheal and flare response for each test. On the basis of analysis of these paired observations, we concluded that there is no significant difference between these two methods of administering prick skin tests.

Adult↗
PubMed1982

Computerized measurement of allergen-induced skin reactions.

The areas of 50 randomly chosen skin-test reactions were measured with a graphics tablet interfaced to a microcomputer. The computer-determined areas were compared with the sums and products of orthogonal diameters, the maximum diameter, and the actual areas of the reactions. The areas measured by the computer were highly correlated with the actual areas (r = 0.999). Both the sums and products of orthogonal diameters were also highly correlated with the actual areas (r = 0.953 and r = 0.988, respectively) and added little to the correlation of the maximum diameter (r = 0.923). The average coefficient of variation for repeated computer area measurements was 5.3%. Area and maximum diameter measurements were then compared in a study designed to evaluate the variation of prick tests applied by different persons. Area measurements revealed significant differences between the testers, which were not found when maximum diameter measurements were compared. Computerized area determination is a rapid, accurate means for quantitating skin-test reactions. The precision offered by this method is of potential importance for studies involving quantitative skin testing.

Allergens↗
PubMed1979

In vivo inactivation of erythrocyte S-adenosylhomocysteine hydrolase by 2'-deoxyadenosine in adenosine deaminase-deficient patients.

The cytotoxic nucleoside 2'-deoxyadenosine is excreted in excessive amounts by individuals with genetic deficiency of adenosine deaminase, and may be in part responsible for the severe combined immune dysfunction from which they suffer. Earlier studies from this laboratory showed that 2'-deoxyadenosine causes the irreversible inactivation of the enzyme S-adenosylhomocysteine hydrolase by an active site-directed, "suicide-like" process. In this communication we have demonstrated similar inactivation of S-adenosylhomocysteine hydrolase in hemolysate and in intact erythrocytes, as well as a striking deficiency of S-adenosylhomocysteine hydrolase activity in the erythrocytes of three adenosine deaminase-deficient patients. In vivo suicide-like inactivation of S-adenosylhomocysteine hydrolase by 2'-deoxyadenosine may contribute to the cytotoxicity of 2'-deoxyadenosine and to the immune dysfunction in adenosine deaminase deficiency.

Adenosine Deaminase↗
PubMed1977

Lymphocyte responses to purified ragweed allergens in vitro. I. Proliferative responses in normal, newborn, agammaglobulinemic, and atopic subjects.

To evaluate cell-mediated immune responsiveness to pollen allergens in atopic subjects, we studied the deoxyribonucleic acid (DNA) synthetic responses of their cultured lymphocytes to purified ragweek antigens E, K, and Ra-3. Since lymphocytes from some highly ragweed-sensitive subjects gave poor proliferative responses when harvested on day 6, we undertook a series of dose-response and time-course studies in atopic and control subjects. Surprisingly, vigorous DNA synthetic responses to antigen E occurred with lymphocytes from all 45 subjects, including 19 highly ragweed-sensitive atopic and control subjects. Surprisingly, vigorous DNA synthetic responses to antigen E occurred with lymphocytes from all 45 subjects, including 19 highly ragweed-sensitive atop adults (8 immunotherapy treated, 11 untreated); 13 nonatopic controls; 4 newborns, and 9 agammaglobulinemic patients. The geometric mean of peak response counts per minute in all 45 subjects was 21,163 and in unstimulated cultures was 2,416 (p = less than 0.0001). The mean day on which the maximal responses occurred was 8.7, and the mean dose eliciting the maximum responses was 59 mug/ml. Statistical comparisons of the stimulated culture data revealed no significant intergroup differences. The finding of vigorous responsiveness to these purified pollen allergens by lymphocytes from nonatopic normal, newborn, and agammaglobulinemic subjects suggests that ragweed pollen antigens are either ubiquitous and lead to cell-mediated responsiveness in all subjects with intact cell-mediated inmunity, or that they may have miogenic properties in addition to their known antigenic properties.

Adult↗
PubMed1976

Severe combined immunodeficiency with leukopenia (reticular dysgenesis) in siblings: immunologic and histopathologic findings.

The hematologic and histologic features of two, nontwin, male siblings with severe combined immunodeficiency and variable granulocytopenia are compared to the four previously reported cases of reticular dysgenesis. These sibs died at 50 and 3 days of age, respectively, with Pseudomonas sepsis and congenital cytomegalovirus infection, respectively. A maternal uncle has selective IgA deficiency. Cord blood from the second sib contained a normal percentage of E-rosetting lymphocytes; however, these lymphocytes failed to respond to mitogenic stimulation in vitro. Erythrocyte and lymphocyte levels of adenosine deaminase were elevated in the father and the second sib. Serum immunoglobulin concentrations were low in both siblings.

Adenosine Deaminase↗