Search PubMed⌕ Search

Biomedical subjects

C E Kahn

Publications and source records attributed to C E Kahn.

52 records · Page 3Linked to original sources
PubMed1990

Family structure: a general program for displaying complex pedigree data.

A general method for automated presentation of complex pedigree data is described. This method, called 'family structure,' allows presentation of genetic relationships for an unlimited number of individuals, and is well suited for description of both human and non-human animal populations. The method is especially useful for populations in which families are interrelated or individuals produce offspring by several mates. This method has been incorporated into a computer system for animal pedigree storage and analysis.

Animals↗
PubMed1988

Combined bone marrow and gallium imaging. Differentiation of osteomyelitis and infarction in sickle hemoglobinopathy.

The clinical records and scintigrams of patients with sickle hemoglobinopathy who underwent combined Tc-99m bone marrow imaging and Ga-67 imaging to differentiate osteomyelitis from bony infarction were reviewed. Of 18 paired examinations in 15 patients, osteomyelitis was diagnosed correctly in six cases; in all six, gallium uptake at the symptomatic site was incongruently increased relative to the bone marrow activity. Of the 12 episodes of infarction, 11 showed congruent activity on both Tc-99m and Ga-67 images. The remaining study was interpreted incorrectly as osteomyelitis due to incongruent Tc-99m and Ga-67 uptake. The use of sequential Tc-99m bone marrow and Ga-67 imaging is an effective means of distinguishing osteomyelitis from bony infarction in patients with sickle hemoglobinopathy.

Adolescent↗
PubMed1987

PHOENIX. An expert system for selecting diagnostic imaging procedures.

The authors developed a computer system that assists physicians in planning the use of diagnostic imaging procedures. This system, the PHOENIX Radiology Consultant, guides the user through a rational, sequential work-up for a variety of common clinical problems. PHOENIX provides explanations of its reasoning, descriptions of the imaging procedures, and citations of relevant literature.

Diagnostic Imaging↗
PubMed1980

A new algorithm for clustering lymphocyte typing sera.

An algorithm is presented for clustering antisera by computer. It has two novel features: the leading serum to which all other sera in the cluster are compared is chosen as the most centrally located serum in the cluster; the similarity between two sera is defined from the 2 X 2 table of serum reactions as s = 2a/(2a + b + c). This similarity index is a better measure of the similarity between two sera than conventional measures of similarity such as the correlation coefficient. Finally, the identification of cluster and serum subsets provides a more complete analysis of cross-reactivity and multispecificity, and suggests which absorptions might yield monospecific typing sera. A computer program which performs this serum cluster analysis is available upon request.

Blood Grouping and Crossmatching↗
PubMedDate not supplied

Brachial plexopathy as a complication of intraarterial cisplatin chemotherapy.

Intraarterial administration of chemotherapeutic agents provides greater local concentration at the tumor site without increased systemic toxicity. Although intravenous infusion of cisplatin is known to cause peripheral neuropathy and intraarterial administration has been reported to cause lumbosacral plexopathy, brachial plexopathy has not been described. We present a case in which infusion of cisplatin into the axillary artery resulted in permanent neurological damage to the posterior cord of the brachial plexus. Proper positioning of the infusion catheter is necessary to minimize potential neural damage.

Adult↗
PubMedDate not supplied

Efficient storage and analysis of immunogenetic phenotypes: the phenotype-element technique.

An efficient means of representing genetic phenotype data is presented. This method employs 'phenotype elements', which are trinary indicators of observed traits. Each phenotype element describes phenotypic information such as an individual's reaction to an antiserum, and assumes a value of positive, negative or unknown. A genotype-phenotype table allows calculation of possible genotypes which correspond to a given phenotype. Applications of the technique are discussed.

Genotype↗
PubMedDate not supplied

Superior temporal gyrus and the course of early schizophrenia: progressive, static, or reversible?

Accumulating evidence suggests alterations in brain structure, especially in the prefrontal and temporal cortex, in schizophrenia. Previous studies examining the progression of brain structural alterations in schizophrenia have led to conflicting results. Morphometric studies of the superior temporal gyrus (STG) volumes were conducted in a series of neuroleptic-naive first-episode schizophrenic patients, non-schizophrenic first-episode psychotic patients, and matched healthy controls. Three-dimensional MRI scans were carried out in these subjects before and after one year of treatment. Volume reductions were seen at baseline in the left superior temporal gyrus (adjusted for intracranial volume) in both of the patient groups. Pretreatment illness duration was inversely related to the volume of the left superior temporal gyrus; this relation was confined to males. One-year follow-up MRI investigations in a smaller subset of patients suggested that the STG volume reductions may be reversible. No significant changes were noted in the STG volumes in matched healthy controls who were also scanned at baseline as well as at one-year follow-up. These findings have implications for understanding the nature of the neuropathological processes in early schizophrenia, as well as the potential impact of early treatment.

Adult↗
PubMedDate not supplied

Standard Generalized Markup Language for self-defining structured reports.

Structured reporting is the process of using standardized data elements and predetermined data-entry formats to record observations. The Standard Generalized Markup Language (SGML; International Standards Organization (ISO) 8879:1986)--an open, internationally accepted standard for document interchange was used to encode medical observations acquired in an Internet-based structured reporting system. The resulting report is self-documenting: it includes a definition of its allowable data fields and values encoded as a report-specific SGML document type definition (DTD). The data-entry forms, DTD, and report document instances are based on report specifications written in a simple, SGML-based language designed for that purpose. Reporting concepts can be linked with those of external vocabularies such as the Unified Medical Language System (UMLS) Metathesaurus. The use of open standards such as SGML is an important step in the creation of open, universally comprehensible structured reports.

Information Storage and Retrieval↗
PubMedDate not supplied

Automatic segmentation of liver structure in CT images.

The segmentation and three-dimensional representation of the liver from a computed tomography (CT) scan is an important step in many medical applications, such as in the surgical planning for a living-donor liver transplant and in the automatic detection and documentation of pathological states. A method is being developed to automatically extract liver structure from abdominal CT scans using a priori information about liver morphology and digital image-processing techniques. Segmentation is performed sequentially image-by-image (slice-by-slice), starting with a reference image in which the liver occupies almost the entire right half of the abdomen cross section. Image processing techniques include gray-level thresholding, Gaussian smoothing, and eight-point connectivity tracking. For each case, the shape, size, and pixel density distribution of the liver are recorded for each CT image and used in the processing of other CT images. Extracted boundaries of the liver are smoothed using mathematical morphology techniques and B-splines. Computer-determined boundaries were compared with those drawn by a radiologist. The boundary descriptions from the two methods were in agreement, and the calculated areas were within 10%.

Biophysical Phenomena↗
PubMedDate not supplied

Randomized testing of alternative survey formats using anonymous volunteers on the World Wide Web.

Consenting visitors to a health survey Web site were randomly assigned to a "matrix" presentation or an "expanded" presentation of survey response options. Among 4,208 visitors to the site over 3 months, 1,615 (38 percent) participated by giving consent and completing the survey. During a pre-trial period, when consent was not required, 914 of 1,667 visitors (55 percent) participated (odds ratio 1.9, P<0.0001). Mean response times were 5.07 minutes for the matrix format and 5.22 minutes for the expanded format (P=0.16). Neither health status scores nor alpha reliability coefficients were substantially influenced by the survey format, but health status scores varied with age and gender as expected from U.S. population norms. In conclusion, presenting response options in a matrix format may not substantially speed survey completion. This study demonstrates a method for rapidly evaluating interface design alternatives using anonymous Web volunteers who have provided informed consent.

Health Status↗
PubMedDate not supplied

Promoting the online use of radiology appropriateness criteria.

Radiology appropriateness criteria and practice guidelines seek to promote the cost-effective use of radiology procedures and interventions and can be most useful when integrated with electronic patient records and order-entry systems. The task of translating practice guidelines into computer-based formats can highlight deficiencies and lead to revisions that make them more useful. Computer-based practice guidelines can include additional didactic material, such as images, videos, sounds, simulations, and links to bibliographic databases. Given patient data, information systems can select the most appropriate intervention automatically; some systems can function autonomously. Knowledge representation schemes can make appropriateness criteria available across a wide variety of computer platforms. Internet-based tools can allow developers to collaborate across an institution or around the globe. Information systems can bring appropriateness criteria to physicians at the point of care. The use of standardized approaches is important to ensure that appropriateness criteria reach the broadest possible audience and that such efforts can be incorporated easily into automated systems.

Artificial Intelligence↗
PubMedDate not supplied

Potential use of extensible markup language for radiology reporting: a tutorial.

One of the main goals of radiology is to communicate imaging information to aid in patient management. Information standards can facilitate communication and help realize this goal. Extensible Markup Language (XML) is a new information transmission standard that was developed to meet the growing need for robust, large-scale World Wide Web applications. XML notation provides a compact document representation scheme that allows radiology reports to be transmitted over the Web as universally understandable, self-defining documents. XML documents can include a report-specific document type definition (DTD) that defines the allowable data fields and values. XML may also be used to generate data entry forms for radiology reporting and help physicians improve the efficiency of the reporting process. XML documents can be used to store reporting results directly, thus allowing pertinent data to be shared on the Web. An XML-based approach can allow users to link information to entities outside the information systems of a given institution. XML-based methods and applications have the potential to promote development of robust radiology reporting systems and integration with broader, enterprise-wide information systems.

Databases as Topic↗
PubMedDate not supplied

Decision-theoretic refinement planning in medical decision making: management of acute deep venous thrombosis.

Decision-theoretic refinement planning is a new technique for finding optimal courses of action. The authors sought to determine whether this technique could identify optimal strategies for medical diagnosis and therapy. An existing model of acute deep venous thrombosis of the lower extremities was encoded for analysis by the decision-theoretic refinement planning system (DRIPS). The encoding represented 6,206 possible plans. The DRIPS planner used artificial intelligence techniques to eliminate 5,150 plans (83%) from consideration without examining them explicitly. The DRIPS system identified the five strategies that minimized cost and mortality. The authors conclude that decision-theoretic planning is useful for examining large medical-decision problems.

Algorithms↗