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Biomedical subjects

J Schroeder

Publications and source records attributed to J Schroeder.

At least 55 records · Page 3Linked to original sources
PubMed1996

Data initiatives: HEDIS and the New England Business Coalition.

The New England Business Coalition is a group of 15 health maintenance organizations, large employers, and health care purchasers operating in the New England area. Formally launched in 1994, the coalition's mission is to standardize health care reporting, improve quality, and allow for comparison of managed health care plans for the participating organizations. The National Committee for Quality Assurance (NCQA) and its measurement instrument, the Health Plan Employer Data Information Set (HEDIS) became involved in the coalition's reporting project in 1992 to help the participating plans fulfill their mission of standardization, quality improvement, and comparative evaluation. In the past 5 years, HEDIS has undergone change and development to meet the needs of both health care plans and purchasers who use the HEDIS information to make decisions about health care for employers. Changes enacted within HEDIS have been brought about with the input of HEDIS users such as the New England Business Coalition, a pilot report card project, and a nationally based HEDIS users group. Future enhancements to HEDIS will result in added value for HEDIS users as development and change continue to meet the evolving needs of plans and purchasers.

Databases, Factual↗
PubMed1995

Damnacanthal is a highly potent, selective inhibitor of p56lck tyrosine kinase activity.

Damnacanthal, an anthraquinone isolated from a plant extract, was found to be a potent, selective inhibitor of p56lck tyrosine kinase activity. The structure, potency, and selectivity of damnacanthal were confirmed by independent synthesis and testing. Damnacanthal exhibited an IC50 of 17 nM for inhibition of p56lck autophosphorylation and an IC50 of 620 nM for phosphorylation of an exogenous peptide by p56lck. Damnacanthal had > 100-fold selectivity for p56lck over the serine/threonine kinases, protein kinase A and protein kinase C, and > 40-fold selectivity for p56lck over four receptor tyrosine kinases. It also demonstrated modest (7-20-fold), but highly statistically significant, selectivity for p56lck over the homologous enzymes p60src and p59fyn. Mechanistic studies demonstrated that damnacanthal was competitive with the peptide binding site, but mixed noncompetitive with the ATP site. Although damnacanthal contains a potentially reactive aldehyde moiety, equilibrium dialysis experiments demonstrated that significant amine formation between damnacanthal and amines occurred only at high concentrations of reactants. However, damnacanthal appeared to bind nonspecifically to membrane lipids and was not active in whole cell tyrosine kinase assays. Damnacanthal is the most potent, selective inhibitor of p56lck tyrosine kinase activity described to date and may represent the starting point for the identification of novel, selective inhibitors of p56lck which are active in whole cell as well as in cell-free systems.

Alkaloids↗
PubMed1995

Activity of N-benzyl-adriamycin-14-valerate (AD198), a new anthracycline derivate, in multidrug resistant human ovarian and breast carcinoma cell lines.

The new lipophilic anthracycline N-benzyl-adriamycin-14-valerate (AD198) was evaluated for its activity in comparison to doxorubicin in P-glycoprotein (Pgp)-positive and -negative cell lines. AD198 and doxorubicin showed comparable antitumor activity in the Pgp-negative breast cancer cell line MCF-7 and the Pgp-negative ovarian carcinoma cell line A2780. By contrast, AD198 was significantly more active than doxorubicin in the Pgp-positive breast cancer cell line MCF7AD (IC50 values 2.5 and 0.15 microM for 96 h continuous exposure) and the Pgp-positive ovarian carcinoma cell line A2780 DX5 (IC50 values 0.6 and 0.07 microM, respectively). Unlike doxorubicin, the activity of AD198 was not increased by concommittant application of cyclosporin A in cell line MCF7AD. Flow cytometry studies showed that, in contrast to doxorubicin, AD198 was not transported by Pgp and that verapamil did not change the intracellular pharmacokinetics of this new anthracycline. These data provide evidence that AD198 possesses high activity in human solid tumor cell lines expressing the classical multidrug resistant phenotype. Its further clinical development appears to be warranted.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1994

Recognition molecules and immunoglobulin domains in invertebrates.

We have used specific antibody probes to conserved antigenic motifs to identify and characterize immunoglobulin-related molecules in tunicates and a C-type lectin found in lamprey that is related to molecules found in tunicates and mammals. The tunicate immunoglobulin cross-reactive molecule (mu CRM) reacts with antibodies raised to shark IgM heavy chains. Intact tunicate mu CRM is a monomer of Ig light-chain-sized subunits and is oligoclonal by IEF. That this molecule is related to Ig is indicated both by immunochemical data and by peptide sequence homologies. The lamprey lectin is a large polymer (> 500,000 kDa) of 35-kDa and 60-kDa subunits. It appears to be related to C-type lectins as shown by peptide sequence homology and the requirement of Ca2+ for activity. Related molecules appear to be present in tunicates and mammals as shown by cross-reactivity of antibodies in Western blots with single bands from hemolymph and T-cell extracts.

Amino Acid Sequence↗
PubMed1994

Patterns of cortical activity in schizophrenia.

Eighty-three patients with schizophrenia and 47 healthy controls received positron emission tomography (PET) with 18F-2-deoxyglucose uptake while they were executing the Continuous Performance Test (CPT). The entire cortex was divided into 16 regions of interest in each hemisphere, four in each lobe of the brain, and data from corresponding right and left hemispheric regions were averaged. Data from the schizophrenic patients were subjected to a factor analysis, which revealed five factors that explained 80% of the common variance. According to their content, the factors were identified and labelled 'parietal cortex and motor strip', 'associative areas', 'temporal cortex', 'hypofrontality' (which included midfrontal and occipital areas) and 'frontal cortex'. Hemispheric asymmetry was only confirmed for the temporal cortex. Factor weights obtained in the schizophrenic group were applied to the metabolic data of the healthy controls and factors scales computed. Schizophrenics were significantly more hypofrontal than the controls, with higher values on the 'parietal cortex and motor strip' factor and a trend towards higher values in the temporal cortex. A canonical discriminant analysis confirmed that the 'hypofrontality' and 'parietal cortex and motor strip' factors accurately separated the schizophrenic group from the healthy controls. Hemispheric asymmetry was only confirmed for the temporal lobe. Significantly higher factor scores for the left temporal lobe in schizophrenics than in normals were obtained when calculated for the right and left hemisphere separately. Taken together, our results confirm the importance of hypofrontality as a pattern of cortical metabolic rate and point to the potential importance of parietal and motor strip function in schizophrenia.

Adult↗
PubMed1993

[Detection of early reperfusion and prediction of left ventricular damage from the course of increased ST values in acute myocardial infarct with thrombolysis].

In 60 patients with acute myocardial infarction (pain < or = 4 h), we examined the value of ST segment monitoring in predicting early reperfusion, resulting left ventricular damage, and complications during hospitalization. Two criteria were determined by observation of the ST segment elevation during the first 4 h following initiation of thrombolysis. Early reperfusion was assessed by an early increase of the creatine phosphokinase (CK) with measurements taken in 15-min intervals. Cardiac catheterization was performed on days 11 +/- 5. According to the CK measurements, a reduction of the ST elevation > or = 50% within 1 h of serial ECG follow-up (ST criterion A) was the best indicator of early reperfusion (sensitivity 84%, specificity 80%, positive predictive value 93%, negative predictive value 67%). Simple comparison of the ST segment in the initial ECG and an ECG recorded 3 h later (ST criterion B) was less accurate according to the detection of early reperfusion (sensitivity 68%, specitivity 93%, positive predictive value 97%, negative predictive value 50%). However, contrary to ST criterion A, criterion B was useful in predicting subsequent left ventricular damage. Patients with a resolution of the initial ST elevation > or = 70%/3 h showed smaller regional wall motion abnormalities (dyssynergic area 21.3 +/- 20.3 vs 33.8 +/- 18.4, p < 0.01) and a better left ventricular ejection fraction (57.7 +/- 11.6 vs 50.2 +/- 12.6, p < 0.05). Patients with early reduction of the ST elevation following either criterion experienced fewer critical events (reinfarction, reischemia, death). In conclusion, the investigated criteria are useful in assessing reperfusion of the infarcted artery following thrombolysis.(ABSTRACT TRUNCATED AT 250 WORDS)

Anistreplase↗
PubMed1991

Hemolysis due to branch pulmonary stenosis after the arterial switch procedure.

An infant with d-transposition of the great arteries underwent arterial switch operation using the modified Jatene technique. Severe bilateral branch pulmonary artery stenosis and mechanical hemolysis subsequently developed. The hemolysis resolved after surgical repair of the stenotic arteries. Probable causes are discussed.

Anemia, Hemolytic↗
PubMed1991

The relationship of residents' autonomy and use of a teaching hospital's resources.

This 1990 study examines the relationship between the degree of use of patient care resources and the degree of supervision of residents by attending physicians (as perceived by residents) at a large midwestern teaching hospital. Ratings of the degree of clinical autonomy allowed residents by 65 attending physicians--each of whom had a general internal medicine practice with a significant hospital component--were provided by 23 former internal medicine chief residents and 17 internal medicine residents who were in their third year at the time of the study. A regression model was used to test the association between hospital resource use (as shown by total hospital charges to patients and their lengths of stay) and the residents' mean ratings of the degrees of autonomy the attending physicians permitted residents, for 7,169 of these physicians' patients discharged between 1986 and 1989 in 28 diagnosis-related groups. The analysis was controlled for patients' insurance status and chronic disease comorbidities. The patients whose attending physicians were rated as allowing substantial clinical autonomy had significantly lower total charges and lengths of stay (p less than .0001). These results suggest that internal medicine residents have an inherently conservative practice style that values low-intensity workups and rapid discharge of patients.

Aged↗
PubMed1990

Detection of a soluble form of the CD30 antigen in sera of patients with lymphoma, adult T-cell leukemia and infectious mononucleosis.

Using a sandwich enzyme-linked immunosorbent assay (ELISA) we were able to detect a soluble form of the CD30 antigen (CD30s) in the supernatant of cell lines expressing membrane-bound CD30 and in T and B cells after transformation with human T-cell leukemia virus (HTLV-I) and Epstein-Barr-Virus (EBV). While CD30s was not found in 250 healthy controls, it was detected in the sera of patients with Hodgkin's disease (23/100), anaplastic large-cell (6/9), angioimmunoblastic (2/2) and one unclassified high-grade non-Hodgkin's lymphoma (NHL), as well as in 18/20 patients with acute adult T-cell leukemia (ATL, HTLV-I-positive). It was absent in a large number of patients with other high-grade NHL, all low-grade NHLs, acute or chronic leukemias and solid tumors. The only non-malignant disease with detectable levels of CD30s was infectious mononucleosis (9/10). The membrane-bound form of CD30 has a molecular weight of 120 kDa. Western blot analysis revealed that CD30s in the serum of patients has a molecular weight of 88 kDa, identical to the antigen released by cell lines in vitro. CD30s disappeared in all originally positive cases after successful treatment and reappeared in relapsing patients. Thus, CD30s may be useful as a specific marker for disease activity of certain types of lymphoma and ATL.

Adult↗
PubMed1989

Arginase of Agrobacterium Ti plasmid C58. DNA sequence, properties, and comparison with eucaryotic enzymes.

Agrobacterium nopaline Ti plasmids code for three enzymes of nopaline [N2-(1,3-dicarboxypropyl)-L-arginine] degradation: nopaline oxidase, arginase, and ornithine cyclodeaminase. We describe the DNA sequence of the arginase gene, a comparison of the deduced protein sequence with eucaryotic arginases, and properties of the procaryotic enzyme. The results show that the agrobacterial arginase is related with arginases from yeast, rat liver, and human liver (28-33% identity). The Ti plasmid enzyme revealed several properties which appear common to all arginases, but it does not utilize L-canavanine as substrate, and its Mn2+ requirement is not satisfied by Fe2+, Co2+, or Ni2+. The properties of arginase and ornithine cyclodeaminase are discussed as part of the mechanisms which avoid depletion of L-arginine and L-ornithine pools for biosynthetic reactions during catabolic utilization of nopaline.

Amino Acid Sequence↗