Search PubMed⌕ Search

Biomedical subjects

K Brooks

Publications and source records attributed to K Brooks.

51 records · Page 3Linked to original sources
PubMed1984

H-40, an antigen controlled by an Igh linked gene and recognized by cytotoxic T lymphocytes. I. Genetic analysis of H-40 and distribution of its product on B cell tumors.

C.B-20 ( Ighb ) mice challenged with BALB/c ( Igha ) spleen cells (or vice-versa) generate cytotoxic T lymphocytes (CTL) that recognize an antigen, H-40, controlled by an Igh-linked gene. The gene maps to the Igh-C region end of the Igh complex, telomeric to Tsu in the region of Pre-1. At least three alleles, a, b, and c, can be defined. Using a cold target competition assay, no polymorphism of the a allele was detected. Both surface Igh-5a positive and negative spleen cells from (C.B-20 X BALB/c)F1 animals express the a allele of the antigen, indicating that this gene is not allelically excluded. Recognition of the target antigen by CTL is restricted by the D-end of H-2d. The tissue distribution of H-40 was explored using both bulk-cultured and cloned CTL. The antigen is expressed on surface immunoglobulin positive (sIg+) cells and correlates with the expression of sIgM. This was determined by analysis of several B lymphomas as well as of other tumors that varied in their extent of expression of sIg. Four subclones of BCL1 were analyzed. Two of the subclones are sIg+ and express H-40, while two other subclones are sIg- and H-40-. Thus, these data define an Igh-linked gene, separate from immunoglobulin structural loci, that controls an antigen expressed on sIg+ cells. Possible mechanisms to account for this finding are discussed.

Alleles↗
PubMed1983

Lymphokine-induced IgM secretion by clones of neoplastic B cells.

The induction of antibody secretion by B cells requires T-cell-derived factors1-5. Such factors have been described1,2,6-12 but the precise relationship among these various factors is not clear, and it has been difficult to demonstrate that these factors act directly on the B cell and do not exert their effect via T cells or macrophages. In this report we describe the direct induction of IgM synthesis and secretion in cloned lines of long-term tissue culture adapted neoplastic B cells (BCL1) by T-cell supernatants from phorbol-12-myristate 13-acetate (PMA)-induced EL-4 cells or concanavalin A (Con A)-induced 7.1.1a cells5,9. We have termed this activity BCDFmu (B-cell differentiation factor for IgM). The supernatants containing BCDFmu induce activated and neoplastic B cells to secrete IgM5 and the factor responsible is distinct from BCGF13, interleukin-2 (IL-2)5, the classical T-cell replacing factor (TRF) described by Schimpl and Wecker5, and immune interferon (IFN gamma)5.

B-Lymphocytes↗
PubMed1983

Multi-element analysis of the human body using neutron activation.

The calibration described is of the Leeds in vivo neutron activation facility for the simultaneous measurement of total body Na, Cl, P, Ca, N and K. The effects of body size and shape have been incorporated into the calibration using a variable anthropomorphic phantom. The main interfering reactions are considered, and the method by which the results are corrected for these interferences described. The accuracy and precision of the technique have been determined. The procedure is suitable for measuring the critically ill since both irradiation and counting are performed with the patient lying supine. For a whole body dose equivalent of 0.5 mSv nitrogen was measured with a coefficient of variation (CV) of 2.2%; potassium was measured in the same counting period with a CV of 1.6%. Using a dose equivalent of 5 mSv sodium (2.2%), chlorine (1.6%) and phosphorus (2.9%) were also determined; for a 10 mSv dose equivalent calcium was measured with a CV of 3%.

Body Composition↗
PubMed1982

Interferences in in vivo neutron activation analysis.

Significant errors can occur in the measurement of the total amounts of N, P, Cl, Na, Ca and K in the human body by in vivo neutron activation analysis because of the presence of interfering activity in the gamma-ray energy spectrum. The interfering activity may be present for two reasons: firstly, patients may have received an administered radioisotope in an unrelated investigation; secondly, activation of elements not normally present in the body in large quantities may have occurred. The size and duration of these errors have been examined for two administered radioisotopes, 67Ga and 47Ca. The interferences due to activated iron and chromium from stainless steel prostheses have been examined, as well as those due to activated iodine and barium in radiographic contrast media. A description of the method by which we correct for those interferences is given. The effects of the shape of the standard spectra used in least squares analysis of the results have been examined.

Activation Analysis↗
PubMed1974

Dancers in darkness.

Explore the source record for details and available documents.

Adaptation, Psychological↗
PubMed1974

Clinical studies on a transformation test for identification of Acinetobacter (Mima and Herellea).

Deoxyribonucleic acid (DNA) from 250 strains of aerobic, nonfermentative, gram-negative coccobacilli and rods were tested for the ability to transform a stable competent auxotroph of Acinetobacter (strain trp E 27) to prototrophy by using the method established by Juni. Several modifications of Juni's original procedure were made to adapt it for use in a clinical diagnostic laboratory. These modifications were directed primarily towards shortening the procedure to allow completion in a time framework consistent with current procedures. The modifications included changes in sterilization temperature, incubation time and temperature of the competent auxotroph and DNA preparation, overnight incubation temperature, and variations in the age of the auxotroph culture when used. Under these conditions, the transformation can easily be performed in 24 h, the final 16 to 18 h being an overnight uninterrupted incubation period. When used in conjunction with the glucose oxidative fermentative basal metabolism test, it provided a rapid highly efficient means for grouping and identifying acinetobacters which is far superior to a biochemical schema. Without exception, the 141 strains of DNA from Acinetobacter species were able to transform the auxotroph to prototrophy. None of the 105 oxidase-positive nonfermenters possessed DNA which was able to transform the Acinetobacter auxotroph to prototrophy.

Acinetobacter↗
PubMed1974

A rapid method for determining decarboxylase and dihydrolase activity.

A total of 764 fresh clinical isolates were used to test a rapid method for determining lysine, arginine, and ornithine decarboxylase activity as well as arginine dihydrolase activity. The conventional Møller decarboxylase broth was tested in parallel with the rapid method on 234 Enterobacteriaceae and 140 non-fermentative Gram-negative rods. The 0.3% agar method was tested in parallel on 245 Enterobacteriaceae and 146 non-fermentors. All media were checked at half-hour or hourly intervals for up to eight hours, with the final reading taken after incubation for 24 hours at 37 degrees C. The rapid method detected 17 positive decarboxylase or dihydrolase reactions that were not detected by the Møller broth and 16 more than the agar medium when testing Enterobacteriaceae. The corresponding figures for the nonfermentative Gram-negative rods were three and two respectively. Lysine and ornithine decarboxylase were generally detected by the rapid broth in two to four hours' incubation while the arginine decarboxylase and dihydrolase were slower and required six to eight hours. This compares with overnight incubation as the general rule for the Møller broth and agar decarboxylases. The comparable accuracy of the rapid method with conventional techniques and the shorter incubation time required for detection of positive reactions make this procedure well suited to a routine clinical laboratory.

Arginine↗
PubMed1967

Behavior of lambda bacteriophage in a recombination deficienct strain of Escherichia coli.

The behavior of lambda phage in the Rec(-) strain JC-1569 is compared with that in the Rec(+) strain JC-1557. No difference deemed significant was noted in the adsorption rate, latent period, burst size, frequency of lysogenization, and frequency of vegetative phage recombination. The location of the prophage and its mode of insertion in the Rec(-) lysogen of wild-type lambda (lambda(+)) were inferred to be normal from the results of conjugational crosses. Spontaneous and ultraviolet (UV) irradiation induction of lambda(+) were markedly reduced in the Rec(-) lysogen. On the other hand, thermal induction of a mutant lambda (lambdacI857) lysogen of the Rec(-) strain was not reduced and was only slightly affected by UV irradiation. Phage subject to inhibition by lambda immunity failed to multiply in UV-irradiated cells of the Rec(-) lambda(+) lysogen, whereas those not inhibited by this immunity did multiply. It was concluded that the failure of UV to induce lambda(+) in the Rec(-) lysogen was not due to damage to the prophage, but rather to the inability of the irradiated cells to respond by lifting immunity. Preliminary evidence indicates that a single mutation confers recombination deficiency and the inability to lift immunity after UV irradiation. Possible relationships between recombination and the lifting of immunity are enumerated.

Coliphages↗
PubMedDate not supplied

Reducing the incidence of ventilator-related pneumonia.

Ventilator-related pneumonia is costly not only in terms of treatment, equipment, and length of stay but also in terms of patient morbidity and mortality. From October 1995 through March 1996 an increase in ventilator-related pneumonia cases, of which 83% were caused by methicillin-resistant Staphylococcus aureus (MRSA), was noted at a Veterans Affairs medical center. A multidisciplinary team based on the TQI model and using TQI tools, methodology, and principles of problem solving was subsequently formed to look into ventilator-related pneumonia. The team's data collection and analysis efforts identified numerous opportunities for improvement. The primary outcome has been a decrease in the incidence of ventilator-related pneumonia that has resulted in substantial cost savings.

Benchmarking↗
PubMedDate not supplied

Variability of adjustments to indices in determining patient risk in biochemical screening.

It has long been appreciated that the measurement of biochemical parameters for prenatal screening for neural tube defects, and later aneuploidy, is not as simple as measuring hemoglobin or hematocrit. Early in the game, it was recognized that there are gestational age curves, and that since alpha-fetoprotein (AFP), for example, is a fetal product, its distribution varies as a function of maternal plasma volume, and therefore the weight of the mother. A number of different adjustment factors have been used for AFP and other parameters for years, with varying degrees of consistency and reliability. Here we review a number of adjustments that have been used, and try to give priority to those that have been most effective. Furthermore, laboratories and programs need to be cognizant that with newer parameters being added, the specifics of requirements will vary on a case-by-case parameter basis, and optimal screening can only be achieved with the appropriate adjustments.

Biomarkers↗