Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 28
Filter
1.
Aust Vet J ; 99(8): 334-343, 2021 Aug.
Article in English | MEDLINE | ID: mdl-34002368

ABSTRACT

This study set out to explore how euthanasia decision-making for animals was taught to students in eight Australasian veterinary schools. A questionnaire-style interview guide was used by a representative at each university to interview educators. Educators were interviewed about their teaching of euthanasia decision-making for four categories of animals: livestock, equine, companion and avian/wildlife. Using thematic analysis, the terms provided by participants to describe how (mode of teaching) and what (specific content) they taught to students were categorised. Information about content was categorised into human-centred factors that influence decision-making, and animal-based indicators used to directly inform decision-making. All eight representatives reported some teaching relevant to euthanasia decision-making at their university for livestock, companion animal and avian/wildlife. One representative reported no such teaching for equid animals at their university. Observation of a euthanasia case was rarely reported as a teaching method. Five universities reported multiple modes of teaching relevant information, while two universities made use of modalities that could be described as opportunistic teaching (e.g., 'Discussion of clinical cases'). Factors taught at most universities included financial considerations, and that it is the owner's decision to make, while animal-based indicators taught included QoL/animal welfare, prognosis and behaviour change. Overall, most universities used a variety of methods to cover relevant material, usually including lectures and several other approaches for all animal types. However, because two universities relied on presentation of clinical cases, not all students at these veterinary schools will be exposed to make, or assist in making, euthanasia decisions.


Subject(s)
Education, Veterinary , Animals , Animals, Wild , Euthanasia, Animal , Horses , Humans , Quality of Life , Students
2.
Aust Vet J ; 98(8): 356-363, 2020 Aug.
Article in English | MEDLINE | ID: mdl-32458445

ABSTRACT

OBJECTIVE: Veterinarians have an important role in supporting and understanding their clients' grief. Veterinary schools have a duty to teach students how best to manage grief - both that of the students/future veterinarians and the clients. This study explores how grief management, associated with ending the life of an animal, was taught to students in eight Australasian veterinary schools. METHODS: A questionnaire-style interview guide was used by a representative at each university to conduct structured interviews with educators in a snowball sampling approach. Educators were interviewed about the teaching of grief management for four categories of animals: livestock, equine, companion and avian/wildlife. The terms used by participants to describe what they taught were grouped into common themes. Teaching was defined by individual participants and included structured and unstructured approaches. The stage in the degree (preclinical or clinical years) that grief management was taught in the veterinary curriculum and by whom (e.g. clinicians or psychologists) is also described. RESULTS: Grief management was taught more in preclinical than clinical years. However, due to how grief was characterised, much of this teaching was general 'nonspecific' teaching that included all categories of animals. Client grief was taught more generically, whereas, grief of veterinarians was taught using specific examples given by clinicians. CONCLUSION: A more robust end-of-life (EoL) management curriculum that includes all aspects of grief management is likely to increase job satisfaction, client happiness and professional satisfaction.


Subject(s)
Education, Veterinary , Veterinarians , Animals , Curriculum , Grief , Horses , Humans , Schools, Veterinary , Students
3.
J Rheumatol ; 37(7): 1488-501, 2010 Jul.
Article in English | MEDLINE | ID: mdl-20551097

ABSTRACT

OBJECTIVE: To determine the prevalence of and independent factors associated with joint involvement in a large population of patients with systemic sclerosis (SSc). METHODS: This study was cross-sectional, based on data collected on patients included in the European League Against Rheumatism (EULAR) Scleroderma Trials and Research (EUSTAR) registry. We queried this database to extract data regarding global evaluation of patients with SSc and the presence of any clinical articular involvement: synovitis (tender and swollen joints), tendon friction rubs (rubbing sensation detected as the tendon was moved), and joint contracture (stiffness of the joints that decreased their range of motion). Overall joint involvement was defined by the occurrence of synovitis and/or joint contracture and/or tendon friction rubs. RESULTS: We recruited 7286 patients with SSc; their mean age was 56 +/- 14 years, disease duration 10 +/- 9 years, and 4210 (58%) had a limited cutaneous disease subset. Frequencies of synovitis, tendon friction rubs, and joint contractures were 16%, 11%, and 31%, respectively. Synovitis, tendon friction rubs, and joint contracture were more prevalent in patients with the diffuse cutaneous subset and were associated together and with severe vascular, muscular, renal, and interstitial lung involvement. Moreover, synovitis had the highest strength of association with elevated acute-phase reactants taken as the dependent variable. CONCLUSION: Our results highlight the striking level of articular involvement in SSc, as evaluated by systematic examination in a large cohort of patients with SSc. Our data also show that synovitis, joint contracture, and tendon friction rubs are associated with a more severe disease and with systemic inflammation.


Subject(s)
Clinical Trials as Topic , Databases, Factual , Inflammation , Joint Diseases , Scleroderma, Localized/pathology , Scleroderma, Systemic , Adult , Aged , Cross-Sectional Studies , Female , Humans , Inflammation/etiology , Inflammation/pathology , Inflammation/physiopathology , Joint Diseases/etiology , Joint Diseases/pathology , Joint Diseases/physiopathology , Joints/pathology , Male , Middle Aged , Range of Motion, Articular , Scleroderma, Localized/etiology , Scleroderma, Systemic/complications , Scleroderma, Systemic/pathology , Scleroderma, Systemic/physiopathology , Synovitis/etiology , Synovitis/pathology , Tendons/pathology
4.
Eur J Epidemiol ; 16(11): 1051-6, 2000.
Article in English | MEDLINE | ID: mdl-11421475

ABSTRACT

STUDY OBJECTIVE: To review the epidemiology of meningococcal disease in Malta over the period 1994-1998, and to identify factors at presentation and in the management of meningococcal disease which may influence mortality. DESIGN: All admissions with meningococcal disease to a national hospital in a population-based study over the period 1994-1998 were studied retrospectively. MAIN RESULTS: Fifty-six cases were diagnosed over 1994-1998, the incidence rising from 0.8/100,000 to 7.2/100,000 total population (p < 0.0001). The median time interval from arrival at hospital to administration of parenteral antibiotic decreased over the 5-year period from 4.4 to 1.2 hours (p = 0.025), with no significant change in the case-fatality rate. There was no association between the time interval from arrival at hospital to parenteral antibiotic administration, and mortality. The following features at presentation were associated with increased mortality: older age (p = 0.03), meningococcaemia compared with meningitis (p = 0.05), shock (p < 0.0001), disseminated intravascular coagulation (p = 0.0001), a normal/low white blood cell count (p = 0.0003), a low platelet count (p = 0.0001) and a high serum creatinine (p = 0.003). CONCLUSIONS: The upsurge of cases in the population was accompanied by a decrease in intervention time in the general hospital, probably due to increased awareness of the disease. This study did not show a positive relationship between early in-hospital administration of antibiotics and improved survival, probably because antibiotics were given earlier to those with fulminant disease and, with therefore, an inherently worse outcome. Stratification of cases by severity on admission is recommended in future studies.


Subject(s)
Meningococcal Infections/epidemiology , Adolescent , Adult , Aged , Chi-Square Distribution , Child , Child, Preschool , Female , Humans , Infant , Logistic Models , Male , Malta/epidemiology , Meningococcal Infections/drug therapy , Middle Aged , Population Surveillance , Prognosis , Retrospective Studies , Statistics, Nonparametric
5.
Adv Exp Med Biol ; 455: 1-6, 1999.
Article in English | MEDLINE | ID: mdl-10599316

ABSTRACT

Although the division of medicine into specialties according to different systems is convenient, it is also artificial: the different systems interact and many diseases overlap both in their pathological features as well as their clinical expression. Many examples of such interactions are seen in the connective tissue disorders, where rheumatological and dermatological manifestations may be prominent features. In some of them the skin rash may be a diagnostic marker (e.g., systemic lupus erythematosus, dermatomyositis). Joint involvement can also be found in "primary" skin disorders such as psoriasis; certain infections can produce both skin and joint manifestations including a number of fairly common viral disorders as well as Lyme borelliosis and the acquired immune deficiency syndrome (A.I.D.S.) The skin may also be the major target of toxicity from a number of drugs, particularly those that are used in the management of rheumatic disorders.


Subject(s)
Rheumatic Diseases/physiopathology , Skin Diseases/physiopathology , Anti-Bacterial Agents/adverse effects , Antirheumatic Agents/adverse effects , Dermatology , Humans , Rheumatology , Skin Diseases/chemically induced , Skin Diseases/diagnosis , Vasculitis, Leukocytoclastic, Cutaneous/chemically induced , Vasculitis, Leukocytoclastic, Cutaneous/physiopathology
6.
Adv Exp Med Biol ; 455: 161-6, 1999.
Article in English | MEDLINE | ID: mdl-10599338

ABSTRACT

The SLE database at the Rheumatology Clinic, St. Luke's Hospital currently includes 62 patients. The presentation, clinical features, ACR criteria and laboratory findings in RNP positive lupus patients [14] were compared to RNP negative subgroup [33]. RNP positivity was significantly associated with Raynaud's phenomenon (p < 0.01), myalgia (p < 0.02), myositis (p < 0.05), neuropsychiatric features (p < 0.05) and Sm positivity (p < 0.01). RNP positive patients had a higher frequency of positive family history, mortality, malar and maculopapular rashes, nail-fold infarcts, telangiectasia, digital vasculitis, photo-sensitivity, arthritis, pleurisy, pericarditis, pericardial effusions, depression, headache, psychosis and TIA.


Subject(s)
Autoantigens/analysis , Lupus Erythematosus, Systemic/immunology , Autoantigens/immunology , Female , Humans , Lupus Erythematosus, Systemic/classification , Lupus Erythematosus, Systemic/physiopathology , Male , Malta , snRNP Core Proteins
7.
Adv Exp Med Biol ; 455: 173-9, 1999.
Article in English | MEDLINE | ID: mdl-10599340

ABSTRACT

The SLE patient database at the Rheumatology Clinic, St. Luke's Hospital includes 62 patients, 58 of which have complete data. The patients were grouped according to sex (7 males vs 51 females). The presentation, clinical manifestations, ACR criteria and laboratory findings of the 2 groups were analyzed and compared. Serositis as the initial manifestation at presentation was significantly commoner in males (29% vs 2%; p < 0.05). Cardiorespiratory problems such as pleurisy, pericarditis, pericardial effusions and myocarditis were more frequent in the male subgroup. Female patients had more arthritis, myositis, neuropsychiatric manifestations (depression, psychosis and headache) anemia, leucopenia and ENA positivity than their male counterparts. All 6 mortalities recorded were in the female subgroup.


Subject(s)
Lupus Erythematosus, Systemic/physiopathology , Female , Humans , Male , Malta , Sex Characteristics
8.
Adv Exp Med Biol ; 455: 227-33, 1999.
Article in English | MEDLINE | ID: mdl-10599348

ABSTRACT

In patients with rheumatoid arthritis, significant positive correlations were found between urinary pyridinium crosslinks and C-reactive protein (CRP), erythrocyte sedimentation rate (ESR) and articular index. Also an inverse correlation was observed between pyridinium crosslinks excretion and grip strength. Glucocorticoid therapy, equivalent to daily doses of 7.5 mg of prednisolone or less, did not appear to have deleterious effect on bone metabolism in these patients as measured by urinary pyridinium crosslinks.


Subject(s)
Arthritis, Rheumatoid/urine , Pyridinium Compounds/urine , Adult , Aged , Arthritis, Rheumatoid/drug therapy , Arthritis, Rheumatoid/metabolism , Arthritis, Rheumatoid/physiopathology , Blood Sedimentation/drug effects , C-Reactive Protein/metabolism , Disease Progression , Glucocorticoids/therapeutic use , Hand Strength , Humans , Middle Aged , Prednisolone/therapeutic use
9.
Adv Exp Med Biol ; 455: 359-65, 1999.
Article in English | MEDLINE | ID: mdl-10599370

ABSTRACT

A number of patients with rheumatoid arthritis attending the Rheumatology Clinic at St Luke's Hospital are currently receiving the drug methotrexate as a second line disease-modifying agent. A survey has been conducted to assess the toxicity profile of methotrexate in 33 of these patients who were followed up for at least 1 year or until they developed side effects necessitating discontinuation of treatment. Adverse effects in this group of patients included haematological ones (6%), asymptomatic elevations of liver enzymes (57%), gastrointestinal (6%) and dermatological side effects (3%). These results have been compared to larger studies performed abroad. Regular monitoring of a complete blood count and liver function tests has helped to detect the more serious side effects of methotrexate at an early stage enabling successful intervention in these patients.


Subject(s)
Antirheumatic Agents/adverse effects , Arthritis, Rheumatoid/drug therapy , Methotrexate/adverse effects , Adult , Aged , Anemia, Macrocytic/chemically induced , Antirheumatic Agents/therapeutic use , Exanthema/chemically induced , Female , Folic Acid/therapeutic use , Gastrointestinal Diseases/chemically induced , Health Care Surveys , Humans , Liver/drug effects , Liver Function Tests , Male , Methotrexate/therapeutic use , Middle Aged , Pancytopenia/chemically induced , Patient Education as Topic , Patient Selection , Risk Factors
10.
Adv Exp Med Biol ; 455: 437-50, 1999.
Article in English | MEDLINE | ID: mdl-10599381

ABSTRACT

We present the results of a preliminary survey carried out on 46 patients with Paget's disease of bone in Malta, 40 of whom were seen at a general medical outpatient clinic and a further 6 at a primary health care centre over the first 6 months of 1997. Various aspects of the disease have been analysed: prevalence, age and sex distribution, familial aggregates, mode of presentation, complications, pattern of bone involvement, a semi-quantitative assay of disease activity as assessed by bone scintigraphy and serum alkaline phosphatase (SAP) levels, and the factors that influenced disease activity. The results have been compared to previous published surveys on Paget's disease in different countries.


Subject(s)
Osteitis Deformans/epidemiology , Adult , Age Distribution , Aged , Alkaline Phosphatase/blood , Female , Humans , Male , Malta/epidemiology , Middle Aged , Osteitis Deformans/complications , Osteitis Deformans/diagnostic imaging , Osteitis Deformans/genetics , Radionuclide Imaging , Sex Distribution
12.
Adv Exp Med Biol ; 455: 547-9, 1999.
Article in English | MEDLINE | ID: mdl-10599397

ABSTRACT

The Churg-Strauss syndrome is characterised by a history of asthma and paranasal sinus disease, eosinophilia of more than 10 per cent, non-fixed pulmonary infiltrates on chest radiography and vasculitis which may affect multiple organ systems. The condition usually manifests in the 4th decade. We present a 21-year old female with a history of asthma since one year of age who developed symptoms and signs of pneumonia, a pulmonary infiltrate on chest radiography and eosinophilia. This was followed a few weeks later by vasculitis which affected the skin and myocardium and associated with a peripheral eosinophilia of more than 80%. Physical examination revealed palpable purpura and signs of left ventricular failure. Echocardiography confirmed significant diminution of left ventricular contractility. A rapid improvement was observed after steroid therapy. Echocardiography after two months showed normal left ventricular function. In this presentation we review the cardiac manifestations of the Churg-Strauss syndrome and its management.


Subject(s)
Churg-Strauss Syndrome/complications , Heart Diseases/etiology , Adult , Asthma/complications , Churg-Strauss Syndrome/drug therapy , Churg-Strauss Syndrome/physiopathology , Electrocardiography , Enalapril/therapeutic use , Female , Furosemide/therapeutic use , Heart Diseases/physiopathology , Heart Diseases/prevention & control , Humans , Immunosuppressive Agents/therapeutic use , Ventricular Function, Left
14.
Biochim Biophys Acta ; 1450(2): 109-18, 1999 Jun 08.
Article in English | MEDLINE | ID: mdl-10354503

ABSTRACT

Although protein kinase C (PKC) has been implicated as an effector of erythropoietin (EPO) production, its exact role is still uncertain. Hep3B human hepatocellular carcinoma cells were used for this study and were depleted of PKC in three different ways: long-term treatment with phorbol 12-myristate 13-acetate (PMA), selective inhibition with calphostin C, and treatment with PKCalpha antisense oligonucleotides. When EPO-producing Hep3B cells were incubated in 1% O2 (hypoxia) for 24 h, PMA treatment resulted in significant decreases in medium levels of EPO in Hep3B cell cultures at concentrations higher than 10 nM. The specific PKC inhibitor, calphostin C, significantly inhibited medium levels of EPO and EPO mRNA levels in Hep3B cells exposed to 1% O2. Western blot analysis revealed that Hep3B cells express the classical PKCalpha and gamma isoforms, as well as novel PKCepsilon and delta and the atypical zeta isoform. Preincubation with PMA for 6 h specifically down-regulated PKCalpha protein expression. Phosphorothioate modified antisense oligonucleotides specific for PKCalpha also decreased EPO production in Hep3B cells exposed to hypoxia for 20 h when compared to PKCalpha sense treatment. The translocation of PKCalpha from the soluble to particulate fractions was increased in Hep3B cells incubated under hypoxia compared with normoxia (21% O2) controls. These results suggest that the PKCalpha isoform plays an important role in sustaining hypoxia-regulated EPO production.


Subject(s)
Erythropoietin/biosynthesis , Isoenzymes/metabolism , Protein Kinase C/metabolism , Cell Hypoxia , Down-Regulation/drug effects , Enzyme Activation , Erythropoietin/genetics , Humans , Isoenzymes/antagonists & inhibitors , Naphthalenes , Protein Kinase C/antagonists & inhibitors , Protein Kinase C-alpha , RNA, Messenger/biosynthesis , Tetradecanoylphorbol Acetate , Tumor Cells, Cultured
15.
Exp Cell Res ; 246(2): 348-54, 1999 Feb 01.
Article in English | MEDLINE | ID: mdl-9925750

ABSTRACT

The program of biochemical and molecular events necessary for commitment to erythroid cell differentiation is particularly well characterized in murine Friend erythroleukemia cell lines. Commitment to hemoglobin synthesis in response to a variety of chemical inducers, including hexamethylene bisacetamide and dimethyl sulfoxide is completed by 24 h and proceeds to terminal differentiation by 96 h. Phorbol 12-myristate 13-acetate, a classical tumor promoter phorbol ester that binds to protein kinase C, blocks differentiation in a reversible manner, suggesting an important role for protein kinase C signaling pathways. The classical protein kinase C isoforms alpha, betaI, and betaII, play distinct roles in the transduction of proliferative and differentiative signals in human, as well as in murine, erythroleukemia cells. Protein kinase Calpha has been implicated in differentiation of human erythroleukemia cells although its translocation to the nucleus has not been observed. Taking advantage of the ability of phorbol 12-myristate 13-acetate to block differentiation in Friend erythroleukemia cells, we determined the localization of the predominant protein kinase C isoforms alpha and betaI during differentiation and in response to their blockade. The ability of phorbol myristate acetate to preferentially diminish protein kinase Calpha-protein localization to the nucleus by 24 h and thereby block differentiation induced by hexamethylene bisacetamide was paralleled by the ability of protein kinase Calpha antisense transfection to block differentiation. In addition, beta-globin transcription, assessed by polymerase chain reaction, was significantly decreased in protein kinase Calpha antisense-transfected cells compared to that seen in vector transfected ones. Taken together, these data suggest an important temporal role for nuclear protein kinase Calpha localization in Friend erythroleukemia cell differentiation.


Subject(s)
Cell Differentiation , Isoenzymes/metabolism , Protein Kinase C/metabolism , Acetamides/pharmacology , Animals , Friend murine leukemia virus , Globins/genetics , Humans , Isoenzymes/genetics , Leukemia, Erythroblastic, Acute , Mice , Oligonucleotides, Antisense , Protein Kinase C/genetics , Protein Kinase C-alpha , Tetradecanoylphorbol Acetate/pharmacology , Transfection , Tumor Cells, Cultured
16.
J Lipid Mediat Cell Signal ; 17(3): 135-50, 1997 Dec.
Article in English | MEDLINE | ID: mdl-9524923

ABSTRACT

Erythropoietin (EPO) is a hormone, as well as a hematopoietic growth factor, that specifically regulates the proliferation and differentiation of erythroid progenitor cells. Although the membrane-bound receptor for EPO has no intrinsic kinase activity, it triggers the activation of protein kinases via phospholipases A2, C, and D. A cascade of serine and threonine kinases, including Raf-1, MAP kinase and protein kinase C (PKC) is activated following tyrosine phosphorylation. In this study, we have examined whether changes in nuclear PKC and 1,2-diacylglycerol (DAG) are induced following EPO treatment of the murine target cell line, B6SUt.EP. Western blot analysis using isoform-specific antibodies demonstrated the presence of PKC beta II, but not PKC alpha, beta I, gamma, epsilon, delta, eta, or zeta in the nuclei of cells stimulated with EPO. The increase in nuclear beta II levels was accompanied by an immediate rise in DAG mass levels with both of the increases peaking by 1 min. These rapid increases in nuclear DAG and PKC beta II expression suggest a mechanism for EPO-induced changes in gene expression necessary for cell proliferation.


Subject(s)
Diglycerides/metabolism , Erythropoietin/pharmacology , Isoenzymes/metabolism , Protein Kinase C/metabolism , Animals , Biological Transport, Active/drug effects , Calcium-Calmodulin-Dependent Protein Kinases/metabolism , Cell Division/drug effects , Cell Line , Cell Nucleus/drug effects , Cell Nucleus/metabolism , Gene Expression/drug effects , Hematopoietic Stem Cells/cytology , Hematopoietic Stem Cells/drug effects , Hematopoietic Stem Cells/metabolism , Kinetics , Mice , Models, Biological , Protein Kinase C beta , Recombinant Proteins , Signal Transduction , Subcellular Fractions/metabolism
18.
Biochem J ; 314 ( Pt 3): 853-60, 1996 Mar 15.
Article in English | MEDLINE | ID: mdl-8615780

ABSTRACT

A murine haematopoietic stem-cell line, B6SUt.EP, responsive to erythropoietin (EPO), has been found to exhibit both early and late changes in diacylglycerol (DAG) and phosphatidic acid (PA) as measured by HPLC and TLC. DAG levels peaked at 5 s with a 28.1% increase compared with control levels (from 17.3 to 22.2 pmol/10(6) cells) with a later peak at 30 min (84.2% increase from 17.3 to 31.9 pmol). These changes were concentration-dependent from 0.025 to 10 units/ml EPO (5 s, EC50=0.82 unit/ml; 30 min, EC50 = 0.10 unit/ml). In addition, PA levels increased 752.3% compared with control levels (from 8.6 to 64.7 micrograms/10(6) cells) with an early peak at 20 s, as measured by both HPLC and TLC (5 s, EC(50)=0.07 unit/ml). G-protein regulation was investigated by studying the effects of the non-hydrolysable GTP analogue guanosine 5'-[gamma-thio]triphosphate (GTP[S]) on PA synthesis. The addition of GTP[S] (10 microM) in permeabilized cells increased PA content from 6.3 micrograms to 48.6 micrograms per 10(6) cells. In the presence of EPO and GTP[S], PA levels increased to 64.8 micrograms. An antagonist of G-proteins, guanosine 5'[beta-thio]diphosphate (GDP[S]), had no effect on control levels of PA (5.9 micrograms/10(6) cells) but blocked the effect of EPO on PA (30.6 micrograms/10(6) cells). Thus, EPO stimulated both lipid second messengers, DAG and PA. Our results demonstrate DAG kinetics to be biphasic, as observed with a high concentration of EPO, or monophasic, as observed with low concentrations of EPO. The PA accumulation preceding that of DAG in the slower and sustaining phase suggests that PA was not derived from DAG. This was confirmed by the stimulation of PA (without ATP) by GTP[S], effectively excluding phosphorylation of DAG by DAG kinase in the formation of PA. In addition, phospholipase D (PLD) activation was demonstrated with a maximal increase in phosphatidylethanol at 5 min, suggesting the EPO increases PA via a guanine nucleotide-binding protein coupled to PLD. The temporal relationship of the evolution of PA and DAG is further strengthened by experiments with ethanol and propranolol as inhibitors of the DAG/PA phosphohydrolase reaction and R59022 as an inhibitor of the DAG kinase reaction.


Subject(s)
Erythropoietin/pharmacology , GTP-Binding Proteins/metabolism , Hematopoietic Stem Cells/metabolism , Phospholipase D/metabolism , Adenosine Triphosphate/pharmacology , Animals , Cell Line , Cell Membrane/drug effects , Cell Membrane/metabolism , Chromatography, High Pressure Liquid , Chromatography, Thin Layer , DNA/biosynthesis , Diglycerides/metabolism , Enzyme Activation , Enzyme Inhibitors/pharmacology , Ethanol/pharmacology , Guanosine 5'-O-(3-Thiotriphosphate)/pharmacology , Guanosine Diphosphate/analogs & derivatives , Guanosine Diphosphate/pharmacology , Hematopoietic Stem Cells/drug effects , Kinetics , Membranes/metabolism , Mice , Phosphatidic Acids/metabolism , Phospholipids/metabolism , Phosphorylation , Propranolol/pharmacology , Pyrimidinones/pharmacology , Thiazoles/pharmacology , Thionucleotides/pharmacology , Thymidine/metabolism
19.
Biochem J ; 314 ( Pt 3): 861-7, 1996 Mar 15.
Article in English | MEDLINE | ID: mdl-8615781

ABSTRACT

The generation of the lipid signalling molecules, diacylglycerol (DAG) and phosphatidic acid (PA), has been implicated in the transduction events essential for proliferation of murine B6SUt.EP stem cells responsive to erythropoietin (EPO). Some of the responses were rapid and transient while others were slower and sustained. In an attempt to better understand the biphasic nature of DAG and PA appearance in response to EPO, an analysis of the molecular species of DAG, phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylinositol (PI), and PA in control and EPO-treated B6SUt.EP cells was made by HPLC and TLC. Fifteen to eighteen species were identified, which were increased non-uniformly by 0.2 unit/ml EPO. Greater increases (x6) were observed in 16:0,20:4 and 18:0,20:4 DAGs than in other species. The molecular species profiles of the stimulated DAGs were compared with the profiles of molecular species contained in the phospholipids. Comparison of the increase in DAG species caused by EPO with the molecular species present in PC and PI showed both PI and PC as the source of the fast DAG accumulation and only PC as the source of the slow DAG accumulation. PE was involved in both phases. We found a consistent formation of ethanolamine over time, in larger amounts than choline, providing strong evidence that, in addition to PC, PE is a major substrate. In addition, changes in molecular species of PA in response to EPO suggest that PI cannot account for the mass of PA formed during the first 30 s incubation with EPO, nor for PA formed during 30 min with EPO. It is concluded that the majority of PA was formed by a direct action of phospholipase D on PC.


Subject(s)
Erythropoietin/pharmacology , Hematopoietic Stem Cells/metabolism , Phospholipids/metabolism , Animals , Cell Line , Choline/metabolism , Diglycerides/analysis , Diglycerides/chemistry , Diglycerides/metabolism , Ethanolamine , Ethanolamines/metabolism , Fatty Acids/analysis , Hematopoietic Stem Cells/chemistry , Hematopoietic Stem Cells/drug effects , Kinetics , Mice , Phosphatidic Acids/metabolism , Phospholipase D/metabolism , Phospholipids/analysis , Phospholipids/chemistry , Time Factors
20.
J Cancer Res Clin Oncol ; 122(8): 465-75, 1996.
Article in English | MEDLINE | ID: mdl-8698746

ABSTRACT

Dexniguldipine hydrochloride (DNIG) is a potent antineoplastic agent with well-documented anti-(protein kinase C) activity and an ability to reverse multidrug resistance. Given the importance of protein kinase C (PKC) activity in proliferation and differentiation, we examined the effect of DNIG on several parameters of Friend erythroleukemia cell (FELC) activity. Particular attention was paid to proliferation, hexamethylene-bisacetamide-(HMBA)-induced differentiation, nuclear localization of protein kinase C, and nuclear protein phosphorylation. P-glycoprotein expression was also followed as an indicator of changes in multidrug resistance. At 2.5 microM, DNIG caused a significant decrease in the rate of FELC proliferation, while maintaining a cellular viability of greater than 80%, whether exposure to the drug was continuous over 96 h or took the form of a 6-h pulse/chase. DNA synthesis was decreased in cells exposed to DNIG for 20 h. Flow cytometry showed a marked increase in the percentage of cells in S phase of the cell cycle. Phosphorylation studies revealed decreased phosphorylation of two nuclear proteins (80 kDa and 47 kDa) following a 4-h exposure to the drug. HMBA-induced differentiation was significantly inhibited with continuous exposure to DNIG, and this effect appears to be a pre-commitment one, as 6-h pulse/chase exposures also resulted in inhibition of differentiation. Cells induced to differentiate with HMBA also demonstrated a decrease in the quantity of the 80-kDa phosphoprotein. Western blotting revealed that, even in the face of decreased phosphorylation, exposure to this PKC inhibitor resulted in an increase in the amount of nuclear PKC alpha. Finally, levels of P-glycoprotein were decreased in the presence of this drug. Our work identifies several effects of the PKC inhibitor DNIG on FELC and suggests several roles for PKC in regulating FELC proliferation and differentiation. Additionally, these results suggest that this PKC inhibitor may increase the effect of other chemotherapeutic drugs, particularly S-phase-specific ones, by increasing the length of S phase and decreasing multidrug resistance. The possibility of combination therapy with DNIG and other antineoplastic agents should be investigated further in light of these findings.


Subject(s)
ATP Binding Cassette Transporter, Subfamily B, Member 1/analysis , Antineoplastic Agents/pharmacology , Dihydropyridines/pharmacology , Nuclear Proteins/metabolism , Protein Kinase C/antagonists & inhibitors , Acetamides/pharmacology , Animals , Cell Cycle/drug effects , Cell Differentiation/drug effects , Friend murine leukemia virus , Leukemia, Erythroblastic, Acute/metabolism , Leukemia, Erythroblastic, Acute/pathology , Mice , Mice, Inbred DBA , Phosphorylation , Tumor Cells, Cultured
SELECTION OF CITATIONS
SEARCH DETAIL
...