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Biomedical subjects

J Kowalczyk

Publications and source records attributed to J Kowalczyk.

At least 73 records · Page 4Linked to original sources

Recombinant human hemoglobin: modification of the polarity of the beta-heme pocket by a valine67(E11)-->threonine mutation.

Using the mutagenesis and a gene expression system previously described [Fronticelli et al. (1991) J. Protein Chem. 10, 495-501], we have replaced Val67E11 in the distal heme pocket of the beta-chains of hemoglobin with Thr. The valine to threonine substitution is isosteric and only modifies the polarity of the beta-heme environment. The absorption and CD spectra of the resultant mutant hemoglobin were essentially the same as that of wild-type protein, indicating that the mutation did not cause any large conformational changes and that a water molecule was not coordinated to the ferrous iron atom. Equilibrium measurements of oxygen binding to the mutant indicate a 2-fold decrease in overall affinity relative to native or wild-type human hemoglobin. Thermodynamic analyses of O2 binding curves, based either on the sequential Adair model or on the MWC two-state model, indicated that the overall decrease of O2 affinity in the system was due to a lower association equilibrium constant for the intermediates of oxygenation, particularly those involved at the third ligation step. The functional characteristics of the mutant hemoglobin in either the T- or R-state were not modified greatly by the mutation; however, the Bohr effect and sensitivity to C1- were increased, suggesting a role of the intermediates of oxygenation in the modulation of these parameters.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗

[Results of treating chronic myelogenous leukemia in children].

Retrospective analysis of the results of treatment chronic myeloid (CML) leukemia in 80 children was done. From among 72 children treated by conventional methods the probability of 10 years survival had 17%. Statistically significant better results was obtained in the group of children with adult than juvenile type of CML (23 and 8%). Allogenic bone marrow transplantation was performed in six children, two children were treated with interferon. New approaches of treatment may offer the better chance for constitution of normal bone marrow function.

Adolescent↗

A new chromogenic assay for direct detection of staphylocoagulase.

Tube test for detection of staphylococcal coagulase, despite of many disadvantages, is commonly used in clinical microbiology for identification of Staphylococcus aureus. In this paper a new chromogenic method for detection of the coagulase directly in staphylococcal cultures is described and evaluated on the basis of a comparison with the standard tube assay. The chromogenic assay appeared to be as sensitive as the tube test but results of the former one can be read in a few hours without any apparatus.

Chromogenic Compounds↗

Using ratios to measure hospital financial performance: can the process be simplified?

Evaluation of a hospital's financial condition is often contingent upon the analysis of financial ratios. This study of 114 Illinois hospitals sought to simplify the financial assessment process by exploring the empirical dimensions that underlie 25 financial ratios. Results of a factor analytic solution suggest that there are five underlying factors which account for approximately 77% of the total variance. Uses of summative scaled measures in health services financial management and research are discussed.

Accounting↗

An analytical review of hospital financial performance measures.

Hospital administrators must have timely, valid, and interpretable financial information that allows them to make operational decisions in response to the threats of the changing health care environment. Aggregate indexes that reflect dimensions of hospital financial performance and simplify the information in financial ratios are needed to aid in decision making. This article reviews the development and use of hospital financial performance measures and lays the groundwork for research into deriving a multidimensional measure.

Decision Support Systems, Management↗

Probe dependence of correlation times in heme-free extrinsically labeled human hemoglobin.

Human heme-free hemoglobin was labeled at beta 93 with either N-iodoacetylaminoethyl-5-naphthalene-1-sulfonate (AEDANS) or fluorescein iodoacetamide (FIA), at beta 1 with pyridoxal-5-phosphate (PLP) and at the heme pocket with anilinonaphthalene-8-sulfonate (ANS). The correlation times associated with these probes ranged from approximately 12 ns for FIA and AEDANS to nearly 20 ns for ANS and PLP. This indicates the presence of internal flexibility in apohemoglobin with librational motions dominated by the mobilities of the monomeric subunits and of the entire dimeric molecules, variously weighted by the different probes. It was not possible to detect motions characterized by correlation times of about 5 ns such as were present in AEDANS-labeled oxyhemoglobin.

Anilino Naphthalenesulfonates↗

Bacterial colonization of ultrasonic nebulizers: implications for frequency of circuit changing.

UNLABELLED: We conducted a prospective study of 50 consecutive postoperative patients over a 5-month period to characterize the bacterial contamination of ultrasonic nebulizers (USNs) after 24, 48, and 72 hours (h) of use. METHODS: Samples of the USN effluent mist and reservoir fluid were cultured and the results were correlated with clinical data from patient records, especially indications of pneumonia or related infections. RESULTS: Two thirds of the USNs were bacteria-free at the three times they were tested. After 24 h, cultures of the mist revealed bacterial growth in only 1 of the 50 patients. After 48 and 72 h, cultures of the mist showed bacterial growth in 6 instances (12%). Colonization of the reservoir fluid was also limited to 1 patient after 24 h. Reservoir-fluid cultures were positive in 10% of the USNs at 48 h and in 18% at 72 h. No clinically significant signs of pneumonia developed in any patient. CONCLUSIONS: These results suggest that colonization of USNs is minimal during the first 72 h of use by postoperative patients with uncomplicated clinical courses and that clinical consequences are unlikely in such patients even when the USN is found to have been colonized. Although the Centers for Disease Control has recommended daily changing of USN circuits, this practice may not be warranted in all clinical settings. Further studies are needed to determine the colonization of USNs used by patients with more complicated clinical courses.

Connecticut↗

The effect of the amount of urea in the diet on the contents of amino acids and other components of duodenal digesta in young bulls.

Young bulls of average live weight 130 kg, with rumen cannulae and re-entrant cannulae of the proximal duodenum, were fed on a diet of maize meal from whole plants, potato starch and a mineral mixture, containing 7.6% crude protein in DM (group IV). For three groups the diet was supplemented to contain about 17.5% crude protein with groundnut oilmeal (group I), grundnut oilmeal and urea, 27 and 31.2% of dietary N (group II) or urea alone (group III). The content of gross energy was similar in all diets. The amount of total N entering the duodenum in groups I to IV was 61.6, 59.2, 49.9 and 38.0 g/day and apparent digestibility of N in the stomachs was -0.4, 5.8, 21.6 and -44.4%. Total amount of amino acids in the duodenal digesta was, in the same order, 257, 261, 215 and 170 g/day, equivalent to 80, 116, 165 and 127% of intake. The ratio of the amounts of essential to nonessential amino acids was in feed 0.84 and in duodenal digesta in all groups 0.98. The amount of lysine in duodenal digesta was 1.5, 2.0, 3.5 and 2.5 times its intake in the same order of the groups.

Amino Acids↗