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Biomedical subjects

P Nadkarni

Publications and source records attributed to P Nadkarni.

25 records · Page 2Linked to original sources
PubMed1988

A prospective, randomized double-blind trial comparing metoclopramide alone with metoclopramide plus dexamethasone in preventing emesis induced by high-dose cisplatin.

We observed 50 patients receiving high-dose cisplatin-based chemotherapy in a prospective, randomized double-blind trial. One group received metoclopramide (MCP) alone (total dose, 6 mg/kg), whereas the other group was given dexamethasone (DMS) (total dose, 60 mg) in addition to MCP. The patient characteristics of the two groups were comparable, confirming satisfactory randomization. Multivariate regression analysis failed to show any statistical significance in the antiemetic response between the two treatment groups. However, female patients receiving Adriamycin (Adria Laboratories, Columbus, OH) concurrently and obese persons exhibited more vomiting. The overall antiemetic response rate was 66%. Because the side effects were minimal, a higher dose of MCP is expected to improve emetic control without increasing toxicity. The use of a 36-hour assessment period in our study gave more meaningful data. An exponential increase in the dose of MCP is probably required, with respect to weight, to obtain the same antiemetic efficacy.

Adult↗
PubMedDate not supplied

Exploring the degree of concordance of coded and textual data in answering clinical queries from a clinical data repository.

OBJECTIVE: To query a clinical data repository (CDR) for answers to clinical questions to determine whether different types of fields (coded and free text) would yield confirmatory, complementary, or conflicting information and to discuss the issues involved in producing the discrepancies between the fields. METHODS: The appropriate data fields in a subset of a CDR (5,135 patient records) were searched for the answers to three questions related to surgical procedures. Each search included at least one coded data field and at least one free-text field. The identified free-text records were then searched manually to ensure correct interpretation. The fields were then compared to determine whether they agreed with each other, were supportive of each other, contained no entry (absence of data), or were contradictory. RESULTS: The degree of concordance varied greatly according to the field and the question asked. Some fields were not granular enough to answer the question. The free-text fields often gave an answer that was not definitive. Absence of data was most logically interpreted in some cases as lack of completion of data and in others as a negative answer. Even with a question as specific as which side a hernia was on, contradictory data were found in 5 to 8 percent of the records. CONCLUSIONS: Using the data in the CDR to answer clinical questions can yield significantly disparate results depending on the question and which data fields are searched. A database cannot just be queried in automated fashion and the results reported. Both coded and textual fields must be searched to obtain the fullest assessment. This can be expected to result in information that may be confirmatory, complementary, or conflicting. To yield the most accurate information possible, final answers to questions require human judgment and may require the gathering of additional information.

Hernia, Ventral↗
PubMedDate not supplied

Exploring performance issues for a clinical database organized using an entity-attribute-value representation.

BACKGROUND: The entity-attribute-value representation with classes and relationships (EAV/CR) provides a flexible and simple database schema to store heterogeneous biomedical data. In certain circumstances, however, the EAV/CR model is known to retrieve data less efficiently than conventionally based database schemas. OBJECTIVE: To perform a pilot study that systematically quantifies performance differences for database queries directed at real-world microbiology data modeled with EAV/CR and conventional representations, and to explore the relative merits of different EAV/CR query implementation strategies. METHODS: Clinical microbiology data obtained over a ten-year period were stored using both database models. Query execution times were compared for four clinically oriented attribute-centered and entity-centered queries operating under varying conditions of database size and system memory. The performance characteristics of three different EAV/CR query strategies were also examined. RESULTS: Performance was similar for entity-centered queries in the two database models. Performance in the EAV/CR model was approximately three to five times less efficient than its conventional counterpart for attribute-centered queries. The differences in query efficiency became slightly greater as database size increased, although they were reduced with the addition of system memory. The authors found that EAV/CR queries formulated using multiple, simple SQL statements executed in batch were more efficient than single, large SQL statements. CONCLUSION: This paper describes a pilot project to explore issues in and compare query performance for EAV/CR and conventional database representations. Although attribute-centered queries were less efficient in the EAV/CR model, these inefficiencies may be addressable, at least in part, by the use of more powerful hardware or more memory, or both.

Database Management Systems↗
PubMedDate not supplied

Integration of multidisciplinary sensory data: a pilot model of the human brain project approach.

The paper provides an overview of neuroinformatics research at Yale University being performed as part of the national Human Brain Project. This research is exploring the integration of multidisciplinary sensory data, using the olfactory system as a model domain. The neuroinformatics activities fall into three main areas: 1) building databases and related tools that support experimental olfactory research at Yale and can also serve as resources for the field as a whole, 2) using computer models (molecular models and neuronal models) to help understand data being collected experimentally and to help guide further laboratory experiments, 3) performing basic neuroinformatics research to develop new informatics technologies, including a flexible data model (EAV/CR, entity-attribute-value with classes and relationships) designed to facilitate the integration of diverse heterogeneous data within a single unifying framework.

Amino Acid Sequence↗
PubMedDate not supplied

UMLS concept indexing for production databases: a feasibility study.

OBJECTIVES: To explore the feasibility of using the National Library of Medicine's Unified Medical Language System (UMLS) Metathesaurus as the basis for a computational strategy to identify concepts in medical narrative text preparatory to indexing. To quantitatively evaluate this strategy in terms of true positives, false positives (spuriously identified concepts) and false negatives (concepts missed by the identification process). METHODS: Using the 1999 UMLS Metathesaurus, the authors processed a training set of 100 documents (50 discharge summaries, 50 surgical notes) with a concept-identification program, whose output was manually analyzed. They flagged concepts that were erroneously identified and added new concepts that were not identified by the program, recording the reason for failure in such cases. After several refinements to both their algorithm and the UMLS subset on which it operated, they deployed the program on a test set of 24 documents (12 of each kind). RESULTS: Of 8,745 matches in the training set, 7,227 (82.6 percent ) were true positives, whereas of 1,701 matches in the test set, 1, 298 (76.3 percent) were true positives. Matches other than true positive indicated potential problems in production-mode concept indexing. Examples of causes of problems were redundant concepts in the UMLS, homonyms, acronyms, abbreviations and elisions, concepts that were missing from the UMLS, proper names, and spelling errors. CONCLUSIONS: The error rate was too high for concept indexing to be the only production-mode means of preprocessing medical narrative. Considerable curation needs to be performed to define a UMLS subset that is suitable for concept matching.

Abstracting and Indexing↗