Margaret Lyman

Procedures for immunochemical study of histamine release from leukocytes with small volume of blood

Abstract Procedures are described for in vitro immunochemical study of release of histamine from leukocytes of peripheral blood. Only 10 ml. blood is required to measure the effect of 10 concentrations of antigen or to carry out 10 tests with individual antigens or compounds. The procedures have been applied extensively for 3 years in a variety of studies, and the convenience, reliability, and usefulness have been demonstrated.

Natural Language Processing and the Representation of Clinical Data

OBJECTIVE Develop a representation of clinical observations and actions and a method of processing free-text patient documents to facilitate applications such as quality assurance. DESIGN The Linguistic String Project (LSP) system of New York University utilizes syntactic analysis, augmented by a sublanguage grammar and an information structure that are specific to the clinical narrative, to map free-text documents into a database for querying. MEASUREMENTS Information precision (I-P) and information recall (I-R) were measured for queries for the presence of 13 asthma-health-care quality assurance criteria in a database generated from 59 discharge letters. RESULTS I-P, using counts of major errors only, was 95.7% for the 28-letter training set and 98.6% for the 31-letter test set. I-R, using counts of major omissions only, was 93.9% for the training set and 92.5% for the test set.

An experiment in automated health care evaluation from narrative medical records.

Abstract This paper describes an experiment in the automatic application of health care evaluation criteria to narrative hospital discharge summaries. The processing of the documents was done in two steps. First a three-stage system for natural language analysis accepted the sentences of each discharge summary as input and produced as output a tabular representation of the information in the document. Second, the health care evaluation criteria were implemented as a set of retrieval routines on this tabular representation. A comparison of the computer-generated evaluation results with those obtained by a physician reviewer showed good agreement, indicating that it is possible to process medical narrative automatically and to perform complex, medically significant fact retrieval on narrative input.

On the measurement of blocking antibody: Blocking of antigenic histamine release compared to maximal antigen binding by antibodies in serum

Abstract A distinction is made between maximum antigen-binding capacity of serum and the degree to which antibodies in serum responsible for such binding may actually block interaction between antigen and sensitized cells. Measurement of histamine release from leukocytes by antigen previously incubated with serum was compared with release by antigen added simultaneously with serum. Antigenic release of histamine was much less blocked when cells, antigen, and serum antibody were brought together simultaneously. Under such circumstances, measurement of the in vitro blocking effect of antibodies on the functional action of antigen in histamine release yielded results which may be found more relevant to clinical manifestations than maximal antigen-binding capacity of serum.

Computerized Language Processing for Multiple Use of Narrative Discharge Summaries

At New York University, computer programs have been developed that convert natural language medical records into a structured data base, i.e. into a table containing the same information as the stored documents. In this form specific information can be quickly retrieved, and summaries of the different kinds of information in the documents can be automatically generated. The automatic conversion of the information from its free-text form to a tabular form is called information formatting. This paper describes the application of the information formatting programs to a small set of pediatric discharge summaries for hospitalizations due to sickle cell disease. The programs created a table of approximately 50 columns in which each different type of information in the documents appeared under a separate heading. From this, a retrieval program extracted instances where symptoms of possible infection preceded symptoms of painful crisis, as suggested by the literature on sickle cell disease. In answer to more detailed queries the program checked the time-order of findings within one document. The potential use of such tables in continuing medical education and other applications in the hospital setting are discussed.

Effects of compounds which inhibit lymphocyte stimulation on the utilization of glucose by leukocytes

Abstract A number of agents are known to inhibit the lymphocyte transformation stimulated in vitro by phytohemagglutinin. Knowledge concerning their modes of action is meager. Leukocytes depend greatly on metabolism of glucose for energy and derivatives needed for synthetic processes. The present study undertook a quantitative examination of the effects of some compounds known to inhibit lymphocyte stimulation on the basic process of glucose metabolism by leukocytes. A high degree of correlation was found between the inhibitory effect on lymphocyte stimulation and suppression of glucose utilization for the quite diverse types of compounds studied. The precise loci or modes of action of the compounds on glucose metabolism of leukocytes remain to be resolved, as is the question of whether disturbance of glucose utilization is a primary or secondary action of compounds inhibitory for lymphocyte stimulation.

Processing free-text input to obtain a database of medical information

The Linguistic String Project of New York University has developed computer programs that convert the information in free-text documents of a technical specialty into a structured form suitable for mapping into a relational database. The processing is based upon the restrictions on the use of language that are characteristic of the subject matter and the document type. These restrictions are summarized in a “sublanguage grammar” that provides a set of word classes and formulas corresponding to the objects and relations of interest in the domain. The programs are independent of the particular sublanguage grammar employed. The application to narrative patient records will be described and the applicability of the methods to other domains discussed.

Computer Structuring of Free-Text Patient Data

This paper will describe ongoing work on developing a computer representation of the information in patient narrative for mapping into a database. Previous papers reported on the design of the database and pilot applications of the system. This paper describes the steps in the text-processing, with particular emphasis on the modules that introduce semantic (i.e. medical) information into the analysis.

61 Quantitative Aspects of Sensitivity in Allergic Children

Procedures were devised for quantitative chemical assay of histamine released by antigens from leukocytes separated from a 10-ml sample of blood. Nine concentrations of antigen can be utilized in each examination to find the amount required for maximum release of histamine or dose response. Studies have been conducted with a variety of antigens for comparison with clinical manifestations and wheal and flare dermal reactions to the antigens. Also the procedures have been employed to measure the capacity of the sera of sensitive persons to inhibit histamine release with specific antigens (presumably by antibodies) and to follow fluctuations in this capacity and in the sensitivity of leukocytes during injection therapy with antigenic extracts. Data have been accumulated from study of over 100 children, including 30 receiving injection therapy. Histamine is released from leukocytes of sensitive subjects by antigens specifically, in agreement with wheal and flare dermal reactions, and the leukocytes of normal non-allergic individuals are unaffected. Sera of normal persons enhance histamine release but the sera of allergic children inhibit histamine release by the antigens specifically involved. During injection therapy the sensitivity of leukocytes to release of histamine by antigen and the capacity of the patients serum to inhibit histamine release may vary independently. The net effects are ascertained by determining the amounts of antigen required for release of 50 % of the total histamine in the cells in the presence of the subjects serum in contrast to normal serum. This comparison affords an objective index of any influence of injection therapy on sensitivity, and an objective means of grouping patients by immunochemical response before undertaking clinical appraisals. (APS)