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Biomedical subjects

R L Alexander

Publications and source records attributed to R L Alexander.

At least 19 recordsLinked to original sources
PubMed2001

High affinity interleukin-3 receptor expression on blasts from patients with acute myelogenous leukemia correlates with cytotoxicity of a diphtheria toxin/IL-3 fusion protein.

Diphtheria fusion proteins are a novel class of agents for the treatment of chemotherapy resistant AML. We prepared DT(388)IL3 composed of human interleukin-3 (IL3) fused to the catalytic and translocation domain of diphtheria toxin (DT(388)) and assessed its activity on patient AML blasts. The number and affinity of IL3 receptors in circulating blasts was measured using a radiolabeled IL3 agonist (SC-65461). Ninety-two percent of patients' blasts had both high and low affinity IL3 receptors. DT(388)IL3 cytotoxicity (>1 log cell kill) was seen in nine of 25 samples (36%). There was a significant correlation between DT(388)IL3 log cell kill and blast high affinity IL3 receptor density (P=0.0044). These results show that specific high affinity IL3 binding is one factor important in the sensitivity of patients' leukemic blasts to DT(388)IL3.

Acute Disease↗
PubMed2001

Oncogene-dependent engraftment of human myeloid leukemia cells in immunosuppressed mice.

We have developed an in vivo model of differentiated human acute myeloid leukemia (AML) by retroviral infection of the cytokine-dependent AML cell line TF-1 with the v-Src oncogene. When injected either intravenously or intraperitoneally into 300 cGy irradiated SCID mice, animals formed multiple granulocytic sarcomas involving the adrenals, kidneys, lymph nodes and other organs. The mean survival time was 34+/-10 days (n = 40) after intravenous injection and 24+/-3 days (n = 5) after intraperitoneal injection of 20 million cells. The cells recovered from leukemic animals continued to express interleukin-3 receptors and remained sensitive to the diphtheria fusion protein DT388IL3. Further, these granulocytic sarcoma-derived cells grew again in irradiated SCID mice (n = 10). The cytogenetic abnormalities observed prior to inoculation in mice were stably present after in vivo passage. Similar to the results with v-Src transfected TF-1 cells, in vivo leukemic growth was observed with TF-1 cells transfected with the human granulocyte-macrophage colony-stimulating factor gene (n = 5) and with TF-1 cells recovered from subcutaneous tumors in nude mice (n = 5). In contrast, TF-1 cells expressing v-Ha-Ras (n = 5), BCR-ABL (n = 5), or activated Raf-1 (n = 44) did not grow in irradiated SCID mice. This is a unique, reproducible model for in vivo growth of a differentiated human acute myeloid leukemia and may be useful in the assessment of anti-leukemic therapeutics which have human-specific molecular targets such as the interleukin-3 receptor.

Animals↗
PubMed2000

Diphtheria toxin fused to human interleukin-3 is toxic to blasts from patients with myeloid leukemias.

Leukemic blasts from patients with acute phase chronic myeloid leukemic and refractory acute myeloid leukemia are highly resistant to a number of cytotoxic drugs. To overcome multi-drug resistance, we engineered a diphtheria fusion protein by fusing human interleukin-3 (IL3) to a truncated form of diphtheria toxin (DT) with a (G4S)2 linker (L), expressed and purified the recombinant protein, and tested the cytotoxicity of the DTLIL3 molecule on human leukemias and normal progenitors. The DTLIL3 construct was more cytotoxic to interleukin-3 receptor (IL3R) bearing human myeloid leukemia cell lines than receptor-negative cell lines based on assays of cytotoxicity using thymidine incorporation, growth in semi-solid medium and induction of apoptosis. Exposure of mononuclear cells to 680 pM DTLIL3 for 48 h in culture reduced the number of cells capable of forming colonies in semi-solid medium (colony-forming units leukemia) > or =10-fold in 4/11 (36%) patients with myeloid acute phase chronic myeloid leukemia (CML) and 3/9 (33%) patients with acute myeloid leukemia (AML). Normal myeloid progenitors (colony-forming unit granulocyte-macrophage) from five different donors treated and assayed under identical conditions showed intermediate sensitivity with three- to five-fold reductions in colonies. The sensitivity to DTLIL3 of leukemic progenitors from a number of acute phase CML patients suggests that this agent could have therapeutic potential for some patients with this disease.

DNA Replication↗
PubMed1992

A new case of IgE myeloma.

We report a case of IgE myeloma in a 78-year-old woman who presented with bone pain in the shoulder and hip and progressive weakness. Except for hypercalcemia, routine chemistry values were within normal limits. Hemoglobin was decreased and the leukocyte count slightly increased. Plasma cells were not observed in the peripheral blood. Serum protein electrophoresis showed a monoclonal protein in the beta-globulin fraction. Immunofixation confirmed the presence of an IgE kappa monoclonal protein. A bone marrow biopsy revealed an interstitial and nodular infiltration of abnormal plasma cells comprising 60% of nucleated cells present. Skeletal roentgenograms and bone scans of this patient showed osteolytic lesions and osteopenia of the thoracic and lumbar spine and osteolytic destruction of the right half of the sacrum. Flow-cytometric analysis of mononuclear cells isolated from peripheral blood showed that 15% of the lymphocytes bound IgE. Using cell-surface markers, we identified 45% of the IgE-positive cells as natural killer cells. Similar results have been found in other diseases marked by increased IgE. The clinical, radiological, and laboratory findings for this patient are compared with previously reported cases of IgE and other types of myeloma.

Aged↗
PubMed1990

Production of plasmid DNA in a simple, inexpensive and reusable fermentor.

Performance data for the production of plasmid DNA in bacterial cultures have been obtained using a new concept of simplified fermentor, the Lofstrand Bactolift. The unique design of this fermentor incorporates a standard 500-ml or 1-liter centrifuge bottle as the bacterial growth vessel, thus eliminating the necessity to transfer the cultures for subsequent processing. Bacterial and plasmid yields have been shown to be equal to or greater than those obtained using conventional shake flasks. Twelve 1-liter Bactolift fermentors can be operated in a standard laboratory water bath that occupies less than two square feet of bench space, as compared to a limit of six 2.8-liter Fernbach flasks containing one liter of culture held in an incubator shaker cabinet that occupies nine square feet of laboratory floor space.

Bacteriological Techniques↗
PubMed1988

Enzyme linked (ELISA) immunoabsorbent assay for the detection of hidden 19S IgM rheumatoid factors in juvenile rheumatoid arthritis.

Determination of hidden IgM rheumatoid factors (RF) in juvenile rheumatoid arthritis (JRA) offers advantages for diagnosis and in following disease activity. Sera from 30 patients with JRA were assayed for RF by latex fixation test (LFT), sensitized sheep cell agglutination test (SCAT), nephelometry, and by ELISA. IgM containing fractions were prepared by chromatography and assayed for hidden RF by the hemolytic method and ELISA. Ten patients were seropositive by LFT. All of them gave positive tests on the serum for RF with the SCAT, nephelometry, and ELISA, and on the IgM containing fractions by the hemolytic assay and ELISA. Seventeen patients seronegative by LFT were positive for hidden RF by the hemolytic test and ELISA on the IgM containing fraction. When unfractionated serum was used, 15 were positive by ELISA. Three patients were seronegative and also negative for hidden RF by the hemolytic assay and ELISA. Thus, only 2 of 30 patients had discordant results between the hemolytic assay on the IgM containing fraction and the ELISA on the serum. Our results indicate the ELISA on the serum in conjunction with the LFT offers a simple, rapid, alternative test for hidden 19S IgM RF in JRA patients.

Agglutination Tests↗
PubMed1986

Evaluation of the Beckman ASTRA enzyme system.

We have evaluated the ASTRA enzyme analyzer. Six enzymes can be analyzed individually or as part of a larger profile of chemistry tests. The system can analyze all six enzymes at a rate of 35-40 specimens per hour. Within-run and day-to-day precision were comparable to that of other enzyme analyzers. A useful feature of the ASTRA enzyme analyzer permits the automatic reassay of specimens having activities that exceed certain defined limits. A comparison of methods for the ASTRA enzyme analyzer with those used on the SMA 12/60 and the ABA-100 showed good correlation with minimal random error.

Alanine Transaminase↗
PubMed1986

Olfactory bulbectomy prevents anti-gonadal effect of exogenous melatonin in male hamsters.

When male Golden hamsters are maintained on short days (less than 12.5 h of light/day) the testes gradually regress. This testicular regression is due to an inhibitory effect of pineal gland melatonin on gonadotropin secretion. A previous report from the author's laboratory has indicated that olfactory bulbectomy (BX) will prevent the testicular regression associated with short photoperiod. The present study examined whether BX would also prevent the testicular regression associated with exogenous melatonin (MEL) injections. Male Golden hamsters were BX or sham (SH) BX at 23-28 days of age and were maintained on 14:10 light-dark cycle. Six weeks following surgery, one half of each surgical group began receiving injections of melatonin (15 micrograms sc), whereas the other half was injected with vehicle at 1600 daily. The testes size of the SH group injected with MEL progressively decreased, whereas the testes of all other groups remained large. These results indicate that BX prevents the testicular regression associated with short photoperiod by interfering with the antigonadotropic effect of melatonin.

Animals↗
PubMed1986

Evaluation of the Hybritech Photon Analyzer and of an improved procedure for choriogonadotropin in serum.

We evaluated the Hybritech Photon Analyzer for its applicability to enzyme immunoassays. This instrument measures absorbances only at 405, 450, and 490 nm. Photometric linearity was good at all three wavelengths. However, the true absorbance range at these wavelengths was 0-1.6 A instead of 0-2.0 A as specified by the manufacturer. We also evaluated the Hybritech "Tandem-E" method for quantifying choriogonadotropin (hCG) in serum. A modification of the recommended procedure improved the precision of the assay. The detection limit of the modified procedure, 1 int. unit/L, permits reliable assays of hCG at concentrations near the upper limit of normal (3 int. units/L). Results by both procedures varied linearly with hCG concentrations up to 250 int. units/L. The Photon Analyzer eliminates the need for manual calculations. Quantitative results agree within +/- 1% with those measured in the "Stasar III" spectrophotometer.

Chorionic Gonadotropin↗
PubMed1983

Rapid determination of hidden rheumatoid factor.

A method for the determination of hidden 19S IgM rheumatoid factor based on separation by QAE-Sephadex A-50 chromatography followed by hemolytic assay is described. Hidden rheumatoid factor titers and IgM recoveries of sera were comparable to those obtained by the conventional acid gel filtration method. The QAE method saves time, requires only 250 microliters of serum and can be performed with a minimum of specialized equipment.

Arthritis, Juvenile↗
PubMed1980

Comparison of radial immunodiffusion and laser nephelometry for quantitating some serum proteins.

After quantitating immunoglobulins G, A, and M and complement C3c and C4 in serum by using a laser nephelometer coupled with a data processor, I compared these results with values obtained by an early-readout radial immunodiffusion method. Day-to-day precision was better for nephelometry than for radial immunodiffusion for all proteins analyzed. The average coefficient of variation was 6.0% for nephelometry and 9.9% for radial immunodiffusion. Comparison of these methods gave ranked correlation coefficients of 0.945, 0.981, 0.932, 0.803, and 0.792 for IgG, IgA, IgM, C3c, and C4, respectively. Nephelometry gave significantly higher values than radial immunodiffusion for IgG, IgA, IgM, and C3c, and significantly lower values for C4 (p less than 0.001). Part of this bias was found to be due to the equation programmed in the data processor for calculating the standard curves. Within 95% limits, nephelometry gave higher normal ranges than radial immunodiffusion for IgG, IgA, and IgM. Other possible factors that can produce this bias are discussed.

Adolescent↗
PubMed1980

Phencyclidine and chemical "stroking".

The current wave of drug abuse is but the latest manifestation of the real human need for "stroking." Drugs which affect the pleasure center of the brain are prime objects of abuse. Phencyclidine ("PCP" or "angel dust") is a cyclohexylamine which has properties of the amphetamine-stimulants, the narcotic-depressants and the hallucinogens. Previously unrecognized population groups include children less than six years of age and pregnant women and their intoxicated offspring. Successful treatment of present and future patients must be multidisciplinary and will ultimately depend upon a clear understanding of the pharmacology, social psychology, politics, and economics of drugs of abuse.

Adolescent↗
PubMed1980

Case report: changes in creatine kinase isoenzymes after myocardial infarction in a patient with prostatic carcinoma.

The detection of serum proteins that can serve as tumor markers has been reported with increased frequency in patients with various localized or metastatic cancers. Many of these reports have concerned patients with prostatic carcinoma, who had normal or increased concentrations of creatine kinase (EC 2.7.3.2) in serum. In many instances the creatine kinase BB isoenzyme was increased in these patients. I describe the case of a patient with carcinoma of the prostate (stage D), who had a myocardial infarction three to four days after admission. The serum activity of the MM, MB, and BB isoenzymes changed markedly after the infarction. These changes and the possible tissue source(s) of this isoenzyme are discussed in relationship to the clinical symptoms of the patient.

Aged↗