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Biomedical subjects

J E French

Publications and source records attributed to J E French.

At least 55 records · Page 3Linked to original sources
PubMed1985

Comparison of the morphology and enzyme activity of mononuclear cells from Fischer 344 rats with either spontaneous or transplanted leukemia.

Mononuclear cell (MNC) leukemia was identified in 26-month-old F344 rats by splenomegaly, reduced red blood cell counts, and elevated white blood cell counts. Atypical MNC were predominant in spleen and blood with acentric nuclei and red cytoplasmic granules. Pentose shunt, glycolytic, and Krebs cycle enzyme activities were elevated 2- to 11-fold in the enriched MNC fraction (Ficoll-Paque density gradients, 1.077 g/ml) isolated from spleen. A leukemic MNC line was derived from one of the spontaneously leukemic donors and then maintained in vivo by s.c. transfer of 2 X 10(7) spleen cells into 7-8-week-old syngeneic recipients. In these serial transplantation experiments leukemia that was clinically and morphologically indistinguishable from spontaneous leukemia in 104-week-old rats was induced in 22-24-week-old rats. Enhanced enzyme activity in MNC was not essential to maintain the phenotypic expression of Fischer rat leukemia. The pattern of biochemical response in spleen MNC from transplanted cases was the opposite of that previously noted in spontaneously leukemic rats, with 50-70% decreases in the specific activities of pentose shunt enzymes and malate dehydrogenase. Reversal of the expression of these enzymes in MNC may be related to a difference in the growth rate of the tumors or to selective proliferation of the transplanted leukemic cells. In addition acetylcholinesterase activity decreased 35-85% in MNC of spleen and blood. Transplantable MNC from F344 rats provide abundant tumorigenic material with a novel biochemical expression that may be useful in the study of chemotherapeutic intervention.

Acetylcholinesterase↗
PubMed1980

Protection of dogs from lethal consequences of endotoxemia with plasma or leukocyte transfusions.

The contribution of cellular and humoral factors of normal blood to resistance to endotoxin was evaluated by selectively transfusing them into beagle dogs prior to IV challenge with a lethal (2.75 mg/kg) dose of Salmonella typhi endotoxin. Supplementation of normal host defenses with 250 ml of plasma containing a heatlabile (56 degrees C for one hour) factor protected the dogs from lethal effects of the toxin. A similar volume of heparinized saline or a lesser volume of plasma (100 ml) was ineffective. The presence of 1 X 10(9) platelets and 7 X 10(10) leukocytes from leukapheresed foxhounds in some transfusion preparations did not affect survival. Protection by treatment with plasma was accompanied by severe tissue injury and loss of circulating platelets and leukocytes. Granulocyte concentrates also afforded protection and decreased tissue injury, as indicated by SGPT and taurine levels. Survivor and nonsurvivor animals experienced an early hyperglycemia as well as elevation of serum glutamic pyruvic transaminase and taurine levels. Thrombocytopenia was great in all experimental groups but was less marked in dogs transfused with cells. Leukopenia was comparable in all groups until six hours after challenge, at which time numbers of circulating leukocytes began a significant return toward normal levels in the cell-transfused group. Impairment of macrophage function was indicated by the depression of the release of colony-stimulating factor in survivor and nonsurvivor animals. Thus, normal plasma alone can protect dogs from endotoxin, but not without a significant amount of injury to the host.

Animals↗
PubMed1979

Blood cultures with the BACTEC 225 radiometric microbial growth detection system.

The BACTEC 225 automated radiometric blood culture system was compared with a conventional blood culture bottle method for its ability to improve the rapid laboratory diagnosis of bacteremia in cancer patients. The BACTEC 225, in combination with routine blind subcultures and smears of radiometrically negative culture vials, detected two thirds, of all positive cultures within 24 h and shortered the detection time generally by 24-48 h. With the recommended growth index setting of 30, radiometrically false-positive findings are rare and are usually due to leukocytosis resulting from infection or leukemia.

Bacteriological Techniques↗
PubMed1978

Improved technique for increased granulocyte recovery from canine whole blood samples by counterflow centrifugation-elutriation. I. In vitro analysis.

Granulocytes were isolated from 120 ml of canine whole blood by a modification in counterflow centrifugation-elutriation technique. The leukocytes were concentrated in a buffy coat fraction and diluted to a fixed RBC density prior to entry into the rotor. Overall recovery of granulocytes from canine whole blood averaged 82% with 96% purity from contaminating mononuclear leukocytes. The purified cellular fraction was assayed in vitro to monitor O2 consumption, chemotaxis, bacterial growth inhibition, and enzyme activities. Cellular integrity was monitored by scanning and transmission electron microscopy as well as by cell volume analysis. The data suggest that the granulocytes isolated by counterflow centrifugation-elutriation suffered no noticeable morphological damage or loss of function in terms of recognition of a toxic agent, migration, phagocytosis, or bactericidal capacity. Granulocytes isolated by counterflow centrifugation-elutriation may be physiologically more active than cells obtained by filtration leukapheresis, continuous-flow centrifugal leukapheresis or discontinuous flow centrifugation both in vitro and in vivo.

Animals↗
PubMed1978

Liquid preservation of canine granulocytes obtained by counterflow centrifugation-elutriation.

Granulocytes (PMN) were isolated from 120 ml of canine whole blood by a modification of the counterflow centrifugation-elutriation technique. Isolated cell suspensions of 96% granulocytes and 4% mononuclear leukocytes with a 21:1 PMN/RBC ratio were stored at 4 degrees C in 4:4:2 medium consisting of four parts HBSS minus Ca++ and Mg++, four parts MEM, twp parts autologous plasma, and 20 microgram/ml gentamicin for 15 days. Granulocytes were stored at concentrations of approximately 4 x 10(6) PMN/ml in polypropylene centrifuge tubes. The stored granulocyte suspensions were assayed in vitro 0, 1, 4, 8, and 15 days to monitor chemotaxis, bacterial growth inhibition, O2 consumption associated with phagocytosis, and enzyme activities. Cell volume analysis was used to evaluate cellular integrity of the liquid-stored granulocytes. Canine granulocytes isolated by the modified dilution technique of counterflow centrifugation-elutriation can be preserved for up to 15 days with 77 +/- 6% granulocyte survival with maintenance of morphological and organelle integrity, as well as retention of in vitro functions of recognition, migration, phagocytosis, and killing of gram-negative bacteria.

Animals↗
PubMed1978

Granulocyte isolation by counterflow centrifugation-elutriation of canine blood obtained by continuous-flow centrifugation leukapheresis.

Granulocytes have been isolated by counterflow centrifugation-elutriation (CCE) from canine leukocyte-rich blood obtained by continuous-flow centrifugation leukapheresis (CFCL). We have attempted to define both the maximal granulocyte recovery and the efficiency of granulocyte purification for the Beckman JE6 elutriation rotor when large volumes of leukocyte rich blood are utilized. The efficiency of granulocyte purification by CCE is 81% (1.31 +/- 0.1 x 10(9) PMNL) if the number of granulocytes entered into the Beckman JE-6 rotor as leukocyte rich blood is limited to 1.60 +/- 0.13 x 10(9) PMNL. Approximately 96 +/- 2% of the leukocytes in the purified fraction were of the granulocytic series with mononuclear leukocytes comprising the residual 4% of the cell population. In vitro analysis of the isolated granulocytes indicated that the cells did not lose their morphological integrity or physiological function as a result of the dual CFCL/CCE procedure relative to granulocytes isolated by CCE from freshly drawn peripheral blood.

Animals↗
PubMed1976

Toxicity of polychlorinated biphenyls (PCBs) to Euglena gracilis: cell population growth, carbon fixation, chlorophyll level, oxygen consumption, and protein and nucleic acid synthesis.

Populations of Euglena gracilis in exponential growth under light were exposed to 2.5, 5.0, 7.5, and 10 ppm of Aroclor 1221. The ID50/48 of Aroclor 1221 was estimated to be 4.4 ppm, while Aroclor 1232 tested at 20, 35, 50, and 100 ppm resulted in an id50/48 of 55 ppm. With Aroclor 1242, no inhibition of growth was observed with up to 100 ppm exposure. Cell cultures exposed to 4.4 ppm of Aroclor 1221 for 48 hrs had a significantly reduced rate of carbon fixation and reduced levels of chlorophyll after correction for cell density. Oxygen consumption was not affected at the ID50 level of the Aroclor. Uptake of [3H]-leucine in treated cultures was twice that of controls, and [3H]-uridine uptake was significantly lower. Uptake of [3H]-thymidine, and incorporation of [3H]-leucine, [3H]-thymidine, and [3H]-uridine were not significantly different in treated and control cultures. Thes results suggest that at the ID50 level, polychlorinated biphenyls (PCBs) reduce cell population growth in Euglena gracilis by inhibition of photosynthesis and/or chlorophyll production.

Animals↗