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Biomedical subjects

M J Murphy

Publications and source records attributed to M J Murphy.

At least 127 records · Page 7Linked to original sources
PubMed1989

Microcapillary clonogenic assays for human marrow hematopoietic progenitor cells.

The capillary clonogenic cell assay was developed and adapted to culture myeloid and erythroid colonies from human bone marrow cells. The plating efficiencies for femoral bone marrow granulocyte-macrophage progenitors (CFU-gm), erythroid colony-forming units (CFU-e) and erythroid burst-forming units (BFU-e) were 0.143%, 0.229% and 0.141%, respectively. Standard bone marrow progenitor Petri dish assays require a total culture volume of 1 ml per dish, and as such are not suitable for the small numbers of cells often obtained from human bone marrow samples. The microcapillary assay as developed and standardized in our laboratory has the unique advantage of being able to utilize small numbers of cells. This technique is suitable for evaluating the myelotoxicity of investigational new anti-cancer and anti-HIV agents and for further investigation of the mechanisms underlying chemotherapy-induced bone marrow toxicity.

Bone Marrow Cells↗
PubMed1989

Effects of prolactin on water balance and kidney function in bullfrog tadpoles.

In four experiments of similar design, stage III-XII bullfrog tadpoles were treated for 5-13 days with either 10 micrograms/day ovine prolactin (PRL) or 10 microliters/day saline (0.7% NaCl). In all cases, saline-treated tadpoles lost ca. 10% of their body weight, whereas PRL-treated animals either maintained their weight or gained slightly. Compared with controls, PRL-treated tadpoles showed a significantly higher water content and a 10-20% increase in inulin space (= extracellular volume). PRL treatment also significantly decreased plasma [Na+] (but not total extracellular [Na+]), and the rates of renal inulin clearance (= glomerular filtration rate) and urine production. PRL-treated tadpoles showed significant retention of the water taken up in response to a salt load. These data suggest that the PRL-induced weight gain observed in bullfrog tadpoles is accompanied by major changes in renal function and the size, water content, and sodium concentration of the extracellular fluid compartment.

Animals↗
PubMed1989

Esophageal perforation following anterior cervical spine surgery.

The authors surveyed the Cervical Spine Research Society to compile a series of esophageal perforations following anterior cervical spine surgery. Twenty-two cases were assembled. Six occurred at the time of surgery, 6 in the postoperative period, and 10 weeks to months later. Eight surgeries were because of fracture. Hardware was implicated in 25% of cases occurring after surgery. Diagnosis was confirmed most often by direct vision at reexploration or esophography. Treatment usually consisted of drainage, repair, and parenteral antibiotics; 2 cases were successfully treated by enteral feeding and antibiotics alone. There was one fatality, and all patients required prolonged hospitalization. Cervical fracture and the use of hardware may be associated with this complication. Clinical suspicion and esophography are important diagnostic tools. Drainage and parenteral antibiotics are recommended treatment.

Adult↗
PubMed1989

Case studies on second-generation anticoagulant rodenticide toxicities in nontarget species.

Specimens from 10 cases of second-generation anticoagulant rodenticide poisoning in dogs and cats were submitted to the Texas Veterinary Medical Diagnostic Laboratory during 1986 and 1987. The clinical signs most frequently observed were lethargy, dyspnea, and ventral hematomas; common necropsy findings included hemoperitoneum, hemothorax, and pulmonary hemorrhage. In the instances when histopathological examination of the tissue was done, it supported a diagnosis of coagulopathy. The presence of anticoagulants in serum or liver was confirmed by high pressure liquid chromatography, gas chromatography/mass spectrometry, or a combination of the two. Five cases of brodifacoum poisoning, 2 of bromadiolone, and 3 of diphacinone toxicity were verified. Concentrations of these rodenticides ranged from approximately 0.001 to 12 ppm.

Animals↗
PubMed1989

Ontogeny of vitamin D action on the morphology and calcium transport properties of the chick embryonic yolk sac.

The ontogeny of the calcium transport properties and hormonal modulation of the yolk sac membrane in amniote embryos is presently poorly understood. We investigated the role of 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3) on plasma calcium values, yolk sac morphology and the ability of the yolk sac membrane to transport 45Ca from yolk to embryo. 1,25-(OH)2D3 treatment caused significant hypercalcaemia in 9-, 12- and 15-day embryos. Additionally, this hormone caused a hypertrophy of the endodermal cell layer that comprises the bulk of the yolk sac membrane. Both of these effects were the most dramatic in the 15-day embryo, the oldest age tested. 45Ca added to the yolk was transported into the blood rapidly across the yolk sac membrane. 1,25-(OH)2D3 significantly enhanced this transport in all age groups. [14C]Inulin was also taken across the yolk sac membrane, but at a slower rate than 45Ca; this transport was unaffected by 1,25-(OH)2D3. Thus, the yolk sac responds to 1,25-(OH)2D3 treatment both morphologically and functionally. The mechanism for transport appears to be a specific one, rather than a simple enhancement of non-specific endocytosis.

Animals↗
PubMed1989

Megakaryocyte colony-stimulating factor and thrombopoiesis.

Although megakaryocyte differentiation and proliferation is understood to be regulated by "humoral" factors, the molecular identities of such factors have, until recently, been obscure. The "two factor" model of megakaryocytopoiesis/thrombopoiesis is critically reviewed. In this model, "Megakaryocyte Colony-Stimulating Factor" (Meg-CSF) determines the early differentiational events of megakaryocytopoiesis, and "Thrombopoietin" (Tpo) is held responsible for the maturation of the megakaryocyte and the biochemical/cytological events in platelet formation and release. To date, neither of these growth factors have been molecularly cloned. When this occurs, the clarification of the roles Meg-CSF, Tpo and other secondary modulators (such as IL-3 and GM-CSF) play in platelet formation in health and disease will be made manifest.

Animals↗
PubMed1989

Determination of brodifacoum and bromadiolone residues in rodent and canine liver.

A method to determine residue concentrations of anti-coagulant rodenticides, brodifacoum (BF) and bromadiolone (BD) in liver was developed, using gas chromatography/mass spectrometry. Nine dogs were given 1.1 mg of BF/kg of body weight, PO, in polyethylene glycol 400, one time. Rats were fed BF or BD (via commercial baits) in amounts from 0.28 to 11.25 mg/kg over 1- to 4-day periods. Fresh liver samples were collected at necropsy from all rats and 3 dogs, ground with Na2SO4, and extracted with CHCl3:MeOH (9:1). After evaporation and silica cartridge purification were performed, residues were oxidized with a 0.16M chromic acid solution, and an oxidation product (4-bromobenzoic acid) was partitioned into CHCl3. The methylated derivative (port derivatization with trimethylanilinium hydroxide) was assayed, using gas chromatography/mass spectrometry. Bromadiolone was detected in livers from rats given greater than 6 mg of BD/kg of body weight, but not in livers of rats given 1.25 mg of BD/kg. In contrast, BF was detected (with one exception) in livers from dogs (given 1.1 mg of BF/kg) and from rats given high (11.25 mg of BF/kg) and low (0.28 mg of BF/kg) doses. This protocol, which does not differentiate between BF and BD because of the formation of a common product after chromic acid oxidation, was used to diagnose anticoagulant toxicosis in 3 dogs, 1 human being and 1 llama naturally poisoned.

4-Hydroxycoumarins↗
PubMed1989

Etiologic agents, incidence, and improved diagnostic methods of cantharidin toxicosis in horses.

In addition to the 3-striped blister beetles (Epicauta temexa and E occidentalis), other sources of equine cantharidin toxicosis were identified at the Texas Veterinary Medical Diagnostic Laboratory and included E albida and E attrivittata and the previously incriminated E pardalis and E pennsylvanica. Improved methods for diagnosing cantharidin or blister beetle toxicosis involve partial purification of urine and gastric content extracts, using silica cartridges, followed by analysis, using capillary gas chromatography/mass spectrometry. During a 26-month period, 53 episodes of cantharidin toxicosis in horses were confirmed at our diagnostic laboratory. Concentrations of cantharidin in urine and gastric contents ranged from 0.0003 to 3.50 micrograms/g. Peak incidences were observed in late summer and early fall.

Animals↗
PubMed1989

A high performance liquid chromatography method for the detection of brodifacoum in serum.

A procedure for the detection of brodifacoum (BDF) in serum was developed. Extraction of BDF was achieved by acidification of 2 ml of serum with 1 ml of 1.5% acetic acid followed by dual extractions with 10 ml diethyl ether and ether: acetonitrile [1:1]. In spiking experiments, 68 +/- 3, 61 +/- 4 and 65 +/- 5% of added BDF was recovered from serum containing 1000, 100 and 25 ng BDF/ml, respectively. Two high performance liquid chromatography solvent systems were used for chromatographic separation (A: 1.5% acetic acid, pH 4.5: acetonitrile [1:2] with 1% dibutylamine; and B:O.2 M tris(hydroxymethyl)aminomethane, pH 7.5:acetonitrile [1:3]). Detection limits were 75 and 3 ng BDF/ml of serum using ultraviolet absorption (254 nm) and fluorescence measurement (313 nm excitation, 375 nm emission), respectively. This method has been used successfully to monitor serum concentrations of BDF in experimental and field cases of exposure.

4-Hydroxycoumarins↗
PubMed1988

Mouse peritoneal macrophages produce CFU-gm and CFU-meg growth-promoting factors.

The effect of peritoneal macrophage-conditioned medium (macrophage CM) from lipopolysaccharide-injected mice on granulocyte-macrophage colony (CFU-gm) and megakaryocyte colony (CFU-meg) formation was examined using a plasma clot culture system. Macrophage CM stimulated mouse bone marrow cells to form CFU-gm and CFU-meg in the presence of pokeweed mitogen-stimulated spleen cell-conditioned medium, but it had no effect on colony formation in the absence of exogenous colony-stimulating factors (CSF). CFU-gm and CFU-meg colony formation was enhanced by low concentrations of exogenous GM-CSF or Meg-CSF alone. These data demonstrate that macrophage CM contains an activity that sensitized CFU-gm and CFU-meg to exogenous CSF.

Animals↗
PubMed1988

Megakaryocyte colony-stimulating factor and burst-promoting activity in LPS-treated mouse spleen cell-conditioned medium.

In order to clarify the mechanism(s) of increased splenic hematopoiesis noted in lipopolysaccharide (LPS)-injected mice, the effects of spleen cell-conditioned medium (SPCM) on megakaryocyte colony (CFU-meg) formation and early erythroid (BFU-e) differentiation were investigated. After spleen cells from LPS-injected mice were incubated for 3 days, the SPCM was assayed for megakaryocyte colony-stimulating factor (Meg-CSF) in CFU-meg assay and for burst-promoting activity (BPA) and erythropoietin (Epo) in erythroid colony assays (i.e., CFU-e, BFU-e). Colony formation of CFU-meg and BFU-e peaked with the addition of 30 and 10-15% SPCM, respectively. Spleen cells from LPS-injected mice produced Meg-CSF and BPA when compared with controls. However, conditioned medium from spleen cells depleted of phagocytic cells had low Meg-CSF and BPA. SPCM did not contain detectable quantities of Epo. It appears likely that local splenic production of Meg-CSF and BPA may affect proliferation of CFU-meg and erythroid progenitor cells in the spleen.

Animals↗
PubMed1988

Effects of an aplastic anemia urinary extract on mouse erythroid progenitor cells in vivo.

We investigated the in vivo effects of a crude extract from the urine of aplastic anemia patients (AA urinary extract) on erythroid precursor cells in the femoral bone marrow and spleens of normal adult mice. A single intraperitoneal injection of AA urinary extract induced a significant increase in the number of splenic erythroid burst-forming units (BFU-e) and erythroid colony-forming units (CFU-e) within 24 h after injection. We then injected pure recombinant erythropoietin (Epo) equivalent to the amount present in the urinary extract. This addition increased the number of splenic CFU-e by almost the same degree as the amount induced by the AA urinary extract 24 h after injection, but failed to elicit any change in the number of splenic BFU-e. In other studies, mice were injected with the same amount of lipopolysaccharide (LPS) and/or pure Epo as that present in the AA urinary extract. Experiments with Limulus amebocyte lysate-adsorbed (endotoxin-depleted) or nonadsorbed (endotoxin-containing) AA urinary extracts showed that endotoxin contamination interfered with the increase in numbers of marrow CFU-e and enhanced the increase in splenic CFU-e numbers induced by pure Epo or Epo activity in the AA urinary extract. The number of splenic BFU-e, however, was not affected by administration of LPS and/or Epo or by adsorbed endotoxin. These data suggest that AA urinary extract contains a stimulating activity for mouse splenic BFU-e, and that this activity is not attributable to the Epo activity or endotoxin contamination within the urinary extract.

Adsorption↗
PubMed1987

The ultrastructure of erythropoiesis in vitro: description and utilization of a new methodology.

A simplified methodology has been developed which makes it possible to examine the ultrastructural details of cells cloned in vitro while retaining the cell/cell relationships within semi-solid cultures. Using mouse erythropoiesis as the model for study, electron microscopy revealed many normal characteristics of red blood cell differentiation and maturation, as well as several distinct dyserythropoietic features. The usefulness of this technology should apply to fine structural studies of clonally-derived material such as hematopoietic cells, tumor cell lines and primary tumor cultures.

Animals↗
PubMed1987

Effects of urinary extracts from patients with idiopathic thrombocytopenic purpura or aplastic anemia on rodent platelet production and megakaryocytopoiesis.

Urinary extracts from idiopathic thrombocytopenic purpura (ITP) patients, aplastic anemia (AA) patients and normal subjects were investigated for their effects on in vivo platelet production, and both in vitro and in vivo megakaryocytopoiesis in rodents. Daily intraperitoneal injection of 1.2 absorbance units (AU, A278) of urinary protein for three consecutive days induced statistically significant increases in rat blood platelet numbers. This increase was observed for 1 of 4 ITP urinary extracts and for all 3 AA urinary extracts, and occurred 24 h after the final injection. In vitro levels of megakaryocyte colony-stimulating factor (Meg-CSF) in ITP urinary extracts were similar to those of normal urinary extracts, and were in dramatic contrast to the markedly elevated levels of Meg-CSF in extracts from AA urine. A single intraperitoneal injection of 0.5 AU of AA urinary protein induced a significant increase in spleen-derived megakaryocyte colony-forming cells (CFU-meg) 48 h past injection. In the group injected with ITP urinary extract, CFU-meg levels remained within normal limits. These results provide evidence that urinary extracts of ITP patients do not contain increased levels of Meg-CSF and a factor which directly stimulates in vivo CFU-meg production, and that the decrease in circulating platelet numbers that is characteristic of ITP patients is not a primary in vivo determinant in the elaboration of these factors.

Anemia, Aplastic↗
PubMed1987

Influence of albumin on granulocyte and macrophage colony-forming efficiency.

Mouse granulocyte and macrophage precursors were assayed in plasma clot and fibrin clot cultures, and the effect of bovine serum albumin (BSA) on colony formation was investigated. The number of granulocyte colonies (CFU-g) and clusters increased as the albumin concentration was increased and the number of macrophage colonies (CFU-m) and clusters concomitantly decreased. The albumin-mediated suppression of macrophage colony formation was overcome by the addition of more than 10% fetal bovine serum (FBS) to the plasma clot culture. The effect of BSA and fatty-acid-free BSA on colony-forming efficiency was also tested in fibrin clot cultures containing 10% FBS. Both BSA and fatty-acid-free BSA at a final concentration of 0.5-2% enhanced CFU-g colony formation, while both forms of BSA reduced the number of CFU-m colonies. However, neither BSA nor fatty-acid-free BSA had any effect on colony formation in FBS-free fibrin clot cultures, and only BSA enhanced colony formation when transferrin, linoleic acid, alpha-thioglycerol and dextran were added to the culture. The number of CFU-g (15.6 +/- 3.1) was higher in cultures containing BSA, transferrin, etc., than the number (9.8 +/- 2.5) in cultures without BSA and including transferrin, etc., than the number (9.8 +/- 2.5) in cultures without BSA and including transferrin, etc. (p less than 0.01). The number of CFU-m (32.0 +/- 6.8) in cultures containing BSA and the other four factors was lower than the number (72.2 +/- 5.6) in the culture without BSA (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Cloning of murine megakaryocyte progenitor cells in a fibrin clot culture system.

A fibrin clot culture system was applied to the cloning of mouse megakaryocyte colony-forming cells (CFU-Meg). The culture medium in this new method consists of Iscove's minimal essential medium containing fetal bovine serum, bovine fibrinogen, bovine thrombin, and pokeweed mitogen-stimulated mouse spleen cell-conditioned medium (PWM-SCM). CFU-Meg colony frequency with 10% PWM-SCM was maximal on days 5-6 of culture. Plating efficiencies averaged 36.1 +/- 3.9 and 51.9 +/- 6.0 per 1.5 X 10(5) BDF1 bone marrow cells and 1.0 X 10(6) spleen cells, respectively. The addition of bovine serum albumin to the culture medium had no effect on the efficiency of megakaryocyte colony growth in this culture system. This simplified and reproducible culture system supported not only the growth of colonies composed of megakaryocytes in "synchronous maturation," but also so-called "heterogenous" megakaryocyte colonies composed of cells in all stages of maturation.

Animals↗