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Biomedical subjects

M J Murphy

Publications and source records attributed to M J Murphy.

At least 163 records · Page 9Linked to original sources
PubMed1985

Effect of hydrocortisone and BCNU on long-term murine bone marrow cultures.

Hydrocortisone (HC) has been observed to influence an in vitro Dexter culture system with maintenance of pluripotent hematopoietic stem cells (CFU-s) and progenitor cells (CFU-gm, BFU-e). In the present study, a two-phase murine Dexter culture system was established to study the mechanism of HC-mediated suppression of stem cells or progenitor cells. Furthermore, the effect of exposing 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) to an adherent cell layer for 1 h was investigated for maintenance of progenitor cells. Cultures supplemented with selenium and transferrin showed relatively good growth. The BFU-e number was significantly enhanced at 2 and 3 weeks of culture in the BCNU-treated group. This system is a good model for monitoring the influence of agents to a hematopoietic-inductive microenvironment.

Animals↗
PubMed1985

A quantitative assay for mouse granulocyte (CFU-g) and macrophage (CFU-m) precursors using plasma clots.

Cytochemical procedures were used to identify and quantitate granulocyte and macrophage precursors from mouse bone marrow cells in plasma clot cultures. Excellent clonal morphology and cellular enzyme activity were obtained when using plasma clots as the support matrix and buffered formalin acetone as the fixative. For cytochemical identification, naphthol AS acetate esterase staining was used for macrophages and peroxidase for granulocytes. These enzyme properties were confirmed by inactivation studies with a variety of inhibitors, group specific chemical modifications, and pinocytotic affinity for horseradish peroxidase. When mouse bone marrow cells (3 X 10(4) cells/dish) were cultured in plasma clots with human placental or L-cell-conditioned medium, 70 to 110 colonies were produced. Both pure granulocyte (CFU-g) and pure macrophage colonies (CFU-m) were observed, but approximately 5% of the total colony number was composed of mixed granulocyte/macrophage colonies (CFU-gm). The number of plated cells correlated strongly with the colony number (0.990 less than r less than 0.999).

Animals↗
PubMed1985

Chemical structure of carbamoylating groups and their relationship to bone marrow toxicity and antiglioma activity of bifunctionally alkylating and carbamoylating nitrosoureas.

Although the antitumor effects of chloroethylnitrosoureas have been shown to be due primarily to DNA-DNA cross-linking by the alkylating moieties of these agents, the basis of the often accompanying bone marrow toxicity has been more controversial. We report on the relative bone marrow toxicity of four model nitrosoureas with different alkylating and carbamoylating activities: 1,3-bis(2-chloroethyl)-1-nitrosourea; 1,3-bis(trans-4-hydroxycyclohexyl)-1-nitrosourea; chlorozotozin, (2-[3-(2-chloroethyl)-3 -nitrosoureido]-2-deoxy-D-glucopyranose); and -3-(beta-D-glucopyranosyl)-1-nitrosourea. Inhibitions of DNA, RNA, and protein synthesis in murine bone marrow cells and of colony growth of myeloid precursor cells (granulocyte-macrophage colony-forming units) were used as in vitro end points of myelotoxicity. Further, we determined the antiglioma activity of the four nitrosoureas on two human gliomas in a clonogenic tumor cell assay and studied the effect of the non-nitrosourea carbamoylators potassium cyanate, chloroethyl isocyanate, cyclohexyl isocyanate, ethyl isocyanate, and ethyl isothiocyanate on granulocyte-macrophage colony-forming units. The results show that, at equivalent drug exposures, clonogenic glioma cell kill was significant and comparative for 1,3-bis(2-chloroethyl)-1-nitrosourea, 1-(2-chloroethyl)-3-(beta-D-glucopyranosyl)-1-nitrosourea, and chlorozotocin; 1,3-bis(trans-4-hydroxycyclohexyl)-1-nitrosourea showed little activity. In contrast, granulocyte-macrophage colony-forming unit toxicity was low with chlorozotocin and 1-(2-chloroethyl)-3-(beta-D-glucopyranosyl)-1-nitrosourea and very high with 1,3-bis(2-chloroethyl)-1-nitrosourea and 1,3-bis(trans-4-hydroxycyclohexyl)-1-nitrosourea. Of the isocyanates, bone marrow toxicity was highest with chloroethyl isocyanate and cyclohexyl isocyanate, intermediate with ethyl isocyanate, and lowest with KOCN and ethyl isothiocyanate. Our results indicate that (a) bifunctional alkylation is essential for antiglioma activity of nitrosoureas and (b) myelosuppression is at least partly linked with carbamoylation but that structural entities in the carbamoylating isocyanate rather than a quantitative degree of carbamoylation determine the degree of potential myelotoxicity.

Alkylating Agents↗
PubMed1984

Catastrophic death losses in a dairy herd attributed to type D botulism.

Clostridium botulinum type D intoxication was diagnosed as the cause of death of 42 of 67 lactating cows in a southeast Texas dairy herd over an 11-day period. By necessity, the diagnosis was based on clinicopathologic findings, as the toxin could not, by standard laboratory tests, be demonstrated in affected cattle. The predominant clinical findings were hindlimb weakness/ataxia rapidly progressing to persistent recumbency. Affected cattle were alert until just before death, which occurred without notable agonal movements or respirations after 6 to 72 hours' recumbency. Abnormal laboratory findings included neutrophilic leukocytosis (all affected cattle), proteinuria (most affected cattle), slight elevations of serum aspartate transaminase and low serum inorganic phosphorus (some affected cattle), and patchy areas of hyperemia/congestion of the mucosa in the small intestine (postmortem examination of 3 affected cattle). This report confirms the findings of others with regard to the difficulty of demonstrating the causative toxin in C botulinum type D-intoxicated cattle and presents available information on the clinicopathologic features of this intoxication that may aid in the differentiation of this condition from other causes of down cows.

Animals↗
PubMed1984

Cholestatic liver dysfunction after long-term phenytoin therapy.

Cholestatic jaundice developed in a 64-year-old woman who had received phenytoin sodium for more than 40 years. Discontinuation of phenytoin therapy resulted in resolution of the hepatic abnormalities, which recurred on rechallenge, strongly suggesting a causal relation to the drug. Phenytoin therapy was discontinued again, with complete resolution of the hepatic abnormalities. The liver biopsy specimen obtained during therapy showed cholestasis compatible with obstruction of the biliary tree, although an obstructive process was never demonstrated. The biochemical abnormalities and histologic features observed most likely represent an unusual response to phenytoin therapy.

Chemical and Drug Induced Liver Injury↗
PubMed1984

Complement sensitivity of erythroid and myeloid precursors in paroxysmal in nocturnal hemoglobinuria.

To test the hypothesis that paroxysmal nocturnal hemoglobinuria (PNH) is a hematopoietic stem cell disorder, the growth of BFU-e and CFU-gm and the complement sensitivity of cultured cells from BFU-e and CFU-gm colonies, as well as of unipotential progenitor cells (CFU-gm and BFU-e), were examined in five PNH patients. BFU-e growth was reduced in the three patients examined, and poor CFU-gm growth was noted in three of the five patients. Compared to normals, BFU-e and CFU-gm colonies in all patients demonstrated an increased susceptibility to the lytic action of complement when the release of 59Fe and myeloperoxidase was measured as specific markers for monitoring membrane damage. Compared to the growth of normal bone marrow cells, CFU-gm growth was significantly inhibited by pretreatment of bone marrow mononuclear cells with monoclonal OKIal antibody and complement. These findings support the proposition that a membrane defect predisposing blood cells to complement-mediated lysis may occur at the level of unipotential progenitor cells.

Colony-Forming Units Assay↗
PubMed1984

The kinetics of hematopoietic stem cells during and after hypoxia. A model analysis.

A previously described mathematical model of the hematopoietic stem cell system has been extended to permit a detailed understanding of the data during and after hypoxia. The model includes stem cells, erythroid and granuloid progenitors and precursors. Concerning the intramedullary feedback mechanisms two basic assumptions are made: 1) The fraction "a" of CFU-S in active cell cycle is regulated. Reduced cell densities of CFU-S, progenitors or precursors lead to an accelerated stem cell cycling. Enlarged cell densities suppress cycling. 2) The self renewal probability "p" of CFU-S is also regulated. The normal steady state is described by p = 0.5, indicating that on statistical average each dividing mother stem cell is replaced by one daughter stem cell, while the second differentiates. Diminished cell densities of CFU-S or enlarged densities of progenitors and precursors induce a more intensive self renewal (p greater than 0.5), such that the stem cell number increases. The self renewal probability declines (p less than 0.5) if too many CFU-S or too few progenitors and precursors are present. The model reproduces bone marrow data for CFU-S, BFU-E, CFU-C, CFU-E, 59 Fe-uptake and nucleated cells in hypoxia and posthypoxia. Although the ratio of differentiation into the erythroid and granuloid cell lines is kept constant in the model, a changing ratio of CFU-E and CFU-C results. The model suggests that stem cells and progenitor cells are regulated by a regulatory interference of erythropoiesis and granulopoiesis.

Cell Differentiation↗
PubMed1984

Characterization of human bone marrow long-term cultures.

In an attempt to more closely simulate the native hematopoietic environment, human bone marrow bony matrix was cultivated in long-term human bone marrow cultures. Sternal bone marrow curettings (i.e., 'bony matrix') were cultured with and without autologous bone marrow single cell suspensions. Fresh media were provided at weekly intervals and the 'harvested' cells were assayed for CFU-gm (i.e., the granulocyte-macrophage precursor). Bone marrow bony matrix alone was not competent to maintain CFU-gm production, although early in the culture nucleated cells and CFU-gm were recruited from the bony matrix. A dose of 850 rad of X-radiation to the bone marrow matrix damaged the hematopoietic growth-promoting effects of the adherent cell layer, which was, however, rapidly reconstituted by an inoculation of intact autologous bone marrow cells. Additional investigations revealed that, whereas the addition of hydrocortisone to this culture system did not alter the maintenance of CFU-gm, recharging the cultures with fresh autologous marrow maintained CFU-gm for 10 weeks. These data indicate that human bone marrow stroma is more sensitive to X-irradiation in vitro than in vivo, and the bone marrow hematopoietic microenvironment provided by its bony matrix seemed to be less effective in vitro than in vivo with respect to the maintenance of hematopoietic precursor cells.

Adult↗
PubMed1984

Dexamethasone-induced increase in in vitro clonogenicity of human neoplasms.

The addition of the corticosteroid hormone, dexamethasone, to the culture medium results in a significant enhancement of tumor colony growth in the human tumor clonogenic assay. Taking 20 as the mean minimum number of colonies per dish that allows evaluation of 122 cultured tumors, 67 were fully evaluable in the presence of dexamethasone whereas only 34 were evaluable when it was omitted. The addition of dexamethasone significantly (P less than .05) increased the number of evaluable tumors by 23. Tumors cultured included those of the breast, lung, colon, ovary, kidney, and stomach. The response to dexamethasone showed a dose-response relationship over a concentration range typical of corticosteroid receptor-mediated reactions, and it appeared to be steroid specific. Possible mechanisms for this hormone effect are discussed.

Breast Neoplasms↗
PubMed1984

1,3 Butanediol treatment of ethylene glycol toxicosis in dogs.

In order to assess the therapeutic value of 1,3 butanediol in ethylene glycol toxicosis, mixed-bred dogs were given an oral dose of commercial antifreeze at 6 ml/kg of body weight (0 hour) and treated (IV) 7 times at 6-hour intervals with 5.5 ml/kg of body weight 1,3 butanediol solution (20% in physiological saline solution) beginning at 8, 12, and 21 hours. Serum glycolic acid concentration was quantitated by high-pressure liquid chromatography. Three dogs that were given ethylene glycol, but no 1,3 butanediol treatment, died with elevated serum glycolic acid concentrations. Five dogs were given ethylene glycol and 1,3 butanediol treatment. Of 2 dogs treated at 8 hours, 1 survived and 1 died at 39 hours; 1 treated at 12 hours and 1 treated at 21 hours survived; 1 dog died soon (27 hours) after treatment was initiated at 21 hours. Four of the 5 dogs had dramatically decreased serum glycolic acid concentrations after 1,3 butanediol treatment, indicating its effectiveness in inhibiting alcohol dehydrogenase-dependent glycolic acid formation in vivo.

Animals↗
PubMed1983

Intracerebral hemorrhage and vasculitis related to ephedrine abuse.

Intracerebral hemorrhage occurred in a 20-year-old man following self-administration of ephedrine. Changes seen on cerebral angiography were typical of vasculitis, and immune complex deposition was found in a skin biopsy. This combination has not previously been reported with ephedrine abuse although it is well known with amphetamine abuse.

Adult↗
PubMed1983

Colony-stimulating activity in murine mixed leukocyte cultures.

Mixed leukocyte cultures (MLC) were prepared utilizing mouse spleen cells from strains with: (1) major histocompatibility complex (MHC) differences, (2) many non-MHC gene differences, and (3) only a few non-MHC gene differences. After 4 days, the conditioned media (CM) of MLC from (1) and (2) above were found to contain high granulocyte/macrophage colony-stimulating activity (CSA) when assayed in methylcellulose clonal cultures. Also the stimulation index (SI) of CSA was elevated on day 4 of incubation, even though 3H-Thymidine (3HTdR) incorporation and SI as measured by 3HTdR increased at 4 and 6 days, respectively. However, MLC-CM from mouse strains with only a few non-MHC gene differences contained low titers of CSA after 4 days in culture, and this was paralleled by a low SI. For MLC with MHC differences, and with many non-MHC gene differences, the response detected by an increase in CSA production appeared more promptly and was perhaps more sensitive when compared with 3HTdR incorporation in the mixed leukocyte reaction (MLR). From these results, we conclude that the presence of CSA in MLC-CM at 4 days of culture represents a good marker for the degree of MLR, and we postulate that the CSA titer in MLC-CM may be relevant for the prediction of graft-versus-host reactions (GvHR).

Animals↗
PubMed1983

The effects of benzene inhalation on murine hematopoietic precursor cells (CFU-e, BFU-e and CFU-gm).

Male B6D2F1 mice were exposed by inhalation to 4000 ppm of benzene for 8 h/day for 1, 2, 3, 5, 7 or 14 days and then sacrificed at 18 h following the last exposure. The cellularities of both femur and spleen were depressed for the duration of benzene exposure. BFU-e/femur declined for 3 days, rebounded to control levels by day 5, and were again depressed by day 7. CFU-e/femur were initially depressed, but by day 7, the concentrations of CFU-e were so elevated that the total number had actually rebounded to slightly higher than control values. CFU-gm/femur remained depressed for the duration of the exposure periods. CFU-e, BFU-e and CFU-gm/spleen were depressed following all exposures. The toxic effects of benzene on hematopoiesis that are immediate are not ascribable to migration of stem cells between femur and spleen. The depressive effects of benzene inhalation on erythropoiesis may be compensated by the rapid proliferation of CFU-e.

Animals↗
PubMed1983

Cation influences on in vitro growth of erythroid stem cells (CFU-e and BFU-e).

Recent developments have focused on long-term bone marrow cultures and serum-free media to establish clonal hematopoiesis in vitro. Prior investigations have suggested an important role for such ingredients as transferrin, albumin, lipid, selenite, and potassium provided by serum. These factors, when present, can support clonal growth even in the absence of serum. Results reported here further define the importance of the cations K+ and Li+ in the regulation of in vitro erythropoiesis in the presence of both normal and dialyzed fetal calf serum and ouabain. While K+ proved essential for optimal erythroid colony formation, the presence of Li+ in such cultures reduced optimal colony formation of erythroid stem cells. This evidence suggests that in long-term marrow cultures or serum-free media K+ is essential for successful maintenance of self-renewal of erythroid stem cells and their differentiation, and that the monitoring of K+ levels may prove useful in such cultures. Since in vitro erythropoiesis was reduced in the presence of Li+, the mechanisms controlling differentiation of hematopoietic stem cell may be interpreted to be subject to cation influence.

Animals↗
PubMed1983

Acute toxicity of fluorinated ether anesthetics: role of 2,2,2-trifluoroethanol and other metabolites.

The fluorinated ethers 2,2,2-trifluoroethyl vinyl ether (TFVE), 2,2,2-trifluoroethyl ethyl ether (TFEE), and 2,2,2-trifluoroethyl allyl ether (TFAE) are lethal to rats pretreated with a variety of cytochrome P-450-inducing agents at doses not toxic to uninduced rats. The hepatic microsomal cytochrome P-450-catalyzed metabolic pathways have been elucidated: TFVE yields 2,2,2-trifluoroethanol (TFE) and glycolaldehyde; TFEE yields TFE and acetaldehyde; and TFAE yields TFE and acrolein. Time courses of metabolite concentrations in blood after administration of toxic doses of metabolites or anesthetics to variously induced rats were compared. For TFVE, phenobarbital (PB) or pregnenolone-16 alpha-carbonitrile (PCN) induction increased acute lethality 3.1- and 2.4-fold respectively, and blood TFE concentrations reached lethal levels. beta-Naphthoflavone (BNF) induction did not produce lethality and TFE concentrations did not reach lethal levels. Glycolaldehyde concentrations did not approximate lethal levels in any case. For TFEE, PB, BNF, or PCN induction increased lethality 3.4-, 2.6-, and 2.0-fold respectively, and TFE concentrations exceeded lethal levels in all cases. Acetaldehyde concentrations did not approximate lethal levels in any case. For TFAE, BNF, or PCN induction increased lethality 3.2- and 4.6-fold respectively, and TFE concentrations approached lethal levels. PB induction did not produce lethality nor did TFE concentrations reach lethal levels. Blood acrolein concentrations could not be determined. Thus the lethal effects of the three anesthetics arise from specific cytochrome P-450 isozyme-catalyzed metabolism to TFE. The relative rates of formation of TFE from the three anesthetics, catalyzed by microsomes from untreated and variously induced rats, supported this conclusion.

Acrolein↗
PubMed1983

Transsphenoidal encephaloceles.

Transsphenoidal encephaloceles are rare congenital anomalies that may be immediately apparent in infants that present with multiple cranial midline defects. They should also be suspected in patients presenting with cerebrospinal fluid rhinorrhea, an epipharyngeal soft tissue mass, a visual defect, or an endocrinologic disturbance, especially when associated with midfacial and optic nerve anomalies. Plain x-ray films of the skull may show absence of the sellar floor and a soft tissue mass; the diagnosis is confirmed by computed tomography scanning. Surgical therapy may be indicated for persistent cerebrospinal fluid rhinorrhea, symptomatic epipharyngeal respiratory distress, or progression of neurological deficits. Two cases of transsphenoidal encephalocele are reported.

Adult↗