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Biomedical subjects

D Sears

Publications and source records attributed to D Sears.

12 recordsLinked to original sources
PubMed1993

Life and death decisions: Mr. H.

Touched by a tragic situation involving one patient's quest for a peaceful, dignified death, a critical care nurse describes the scenario involved. A compassionate resolution can be reached by examining all medical aspects--psychosocial as well as physical. Decisions affect not only our patients and their families, but ultimately our profession.

Attitude of Health Personnel↗
PubMed1991

High-efficiency yeast artificial chromosome fragmentation vectors.

Chromosome fragmentation vectors (CFVs) are used to create deletion derivatives of large fragments of human DNA cloned as yeast artificial chromosomes (YACs). CFVs target insertion of a telomere sequence into the YAC via homologous recombination with Alu repetitive elements. This event results in the loss of all YAC sequences distal to the site of integration. A new series of CFVs has been developed. These vectors target fragmentation to both Alu and LINE human repetitive DNA elements. Recovery of deletion derivatives is ten- to 20-fold more efficient with the new vectors than with those described previously.

Chromosomes, Fungal↗
PubMed1986

The diagnostic usefulness of measuring antineutrophil antibodies in neutropenic patients.

We prospectively evaluated the usefulness of measuring antineutrophil (PMN) antibodies in patients with neutropenia by a sensitive immunoassay. The result of the immunoassay were compared to a standard leukoagglutination test. Thirty-two patients with neutropenia were studied. The mean value (+/- 1 SD) for PMN-bound IgG for 43 normal controls was 121 +/- 29 fg/PHN. All fifteen patients with immune neutropenia had elevated plasma levels of anti-PMN antibody (191-2,000 fg/PMN). The leukoagglutination assay was positive in 10 of these 15 patients. In 17 patients with nonimmune neutropenia, the mean value (+/- 1 SD) for PMN-bound IgG was 120 +/- 22 fg. Seventeen patients with sero-positive rheumatoid arthritis but normal PMN counts were also studied. These patients' plasmas bound 447 +/- (1 SD) 201 fg IgG/PMN. The leukoagglutination test was negative in these patients. Our study shows that the immunoassay is more sensitive than leukoagglutination testing for diagnosing immune neutropenia. Nonimmune, neutropenic patients' plasmas showed no increased reactivity. In nonneutropenic patients who have high titers of rheumatoid factor, immunoreactivity against PMN is measured by the immunoassay, but not by leukoagglutination testing. Binding assays may be more sensitive than leukoagglutination testing for measuring anti-PMN antibodies; however, in some cases, specificity of such testing may be increased with leukoagglutination testing.

Agglutination Tests↗
PubMed1985

A simplified radioimmunoassay for antibodies causing immune cytopenia.

A two-step, solid-phase radioimmunoassay for the measurement of antibodies directed against platelets, neutrophils, and red blood cells is described. Cells to be tested or standard solutions of human IgG (HIgG) first are incubated with excess 125I goat anti-human IgG. Unbound 125I anti-IgG is adsorbed in a second step to polystyrene balls (PB) coated with excess human IgG. Inhibition of binding in this second step is related directly to the level of cell associated IgG. The amount of cell bound IgG is determined by comparison to a inhibition curve for standard IgG solution. The method was evaluated by quantitating antibody levels in patients with clinical evidence of immune cytopenias.

Antibodies↗
PubMed1985

Electronic blood cell counters. Faulty calibration due to type and amount of anticoagulant in collection tubes.

Electronic blood cell counters calibrated for mean corpuscular volume against normal venous blood collected in K3 EDTA (using a microhematocrit centrifuge) consistently yielded unacceptable data when used to assay commercial control materials. After recalibration using samples collected in Na2 EDTA acceptable results were obtained. Both types of sample tubes probably contained excess anticoagulant, and plasma was hypertonic in both. However, blood collected in Na2 EDTA had a lower pH, and the consequent swelling of RBCs due to a low pH compensated for osmotically induced shrinkage when microhematocrit values were measured.

Anticoagulants↗
PubMed1975

Ocular effects of a 325 NM ultraviolet laser.

Corneal exposures were made on 100 eyes of anesthetized rhesus monkeys with a continuous wave HeCd ultraviolet laser at a wavelength of 325 nm. The ED-50 corneal damage probability point was determined to be 0.8 joules of energy. This is higher than the levels for damage reported for noncoherent ultraviolet sources. However, the endpoint used here was a well-defined circumscribed lesion as contrasted to the appearance of granules used for the broad band, wide-beam, noncoherent studies. The granules were not seen with the narrow band, small beam laser irradiation. Exposures made with 6.5 joules of energy produced lens damage, i.e., cataracts. This represents permanent damage as compared to the corneal damage which at threshold levels is completely reversible in 24-48 hours.

Animals↗
PubMedDate not supplied

The cytologic diagnosis of malignant neoplasms in pleural and peritoneal effusions.

This study presents data on 3,011 pleural and peritoneal effusion specimens that were examined over a three-year period (1982 to 1984). Totals of 812 (44%) of 1,846 pleural and 423 (36%) of 1,165 peritoneal specimens were positive for malignant cells. While 535 patients had malignant pleural effusions, 254 patients had malignant peritoneal effusions, and 57 had both malignant pleural and peritoneal effusions. The most common primary neoplasms causing malignant pleural effusions were carcinomas of breast (24%) and lung (19%) and lymphoreticular neoplasms (16%). The most common primary neoplasms causing malignant peritoneal effusions were carcinomas of ovary (32%) and breast (13%) and lymphoreticular neoplasms (7%). There was an average interval of more than 30 months between the histologic diagnosis of the primary neoplasm and the diagnosis of malignant effusions in patients with carcinoma of breast, lymphoreticular neoplasm and malignant melanoma. The average time until death following the diagnosis of a malignant effusions was five months or less, except for patients with carcinoma of the breast and carcinoma of the ovary. One hundred twenty-five patients (15%) presented with malignant effusions caused by neoplasms of unknown primary sites. The most common primary neoplasms that were later diagnosed were, in decreasing order of frequency, carcinoma of the ovary, carcinoma of the lung and lymphoreticular neoplasms.

Adolescent↗