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1.
J Psychiatr Ment Health Nurs ; 18(5): 375-85, 2011 Jun.
Article in English | MEDLINE | ID: mdl-21539682

ABSTRACT

The study aimed to explore the effectiveness of a mental health screening and referral clinical pathway for generalist community nursing care of war veterans and war widow(er)s in Australia on outcomes of client self-reported mental health, quality of life, and client and carer satisfaction. The pathway was developed by literature review and consultation, then trialled and evaluated. Validated screening tools were embedded within the pathway to support generalist nurses' mental health decision making. Pre- and post-measures were applied. Clients on whom the pathway was trialled were invited to complete an evaluation survey questionnaire, as were their informal carers. Most clients and carers who responded to these questionnaires were highly satisfied or satisfied with care provided through application of the pathway. This study adds understanding about one way that community nurses might identify people with mental health difficulties. The trialled pathway, which was modified and refined following the study, is now available on the Internet as an evidence-based resource for community nurses in Australia to guide practice and maximize holistic care for war veterans and war widow(er)s where that care is funded by Department of Veterans' Affairs.


Subject(s)
Community Health Nursing , Critical Pathways , Mass Screening/nursing , Mental Disorders/nursing , Outcome and Process Assessment, Health Care , Patient Satisfaction , Referral and Consultation , Veterans/psychology , Widowhood/psychology , Aged , Aged, 80 and over , Anxiety Disorders/diagnosis , Anxiety Disorders/nursing , Australia , Benchmarking , Combat Disorders/diagnosis , Combat Disorders/nursing , Comorbidity , Depressive Disorder, Major/diagnosis , Depressive Disorder, Major/nursing , Evidence-Based Nursing , Feasibility Studies , Female , Humans , Male , Mental Disorders/diagnosis , Stress Disorders, Post-Traumatic/diagnosis , Stress Disorders, Post-Traumatic/nursing
2.
J Psychiatr Ment Health Nurs ; 16(2): 129-36, 2009 Mar.
Article in English | MEDLINE | ID: mdl-19281543

ABSTRACT

There is a growing need for advanced practice mental health and drug and alcohol nursing roles in the care of people living with HIV/AIDS; however, limited publications address these domains. This study evaluated a community-based mental health drug and alcohol nurse role caring for people living with HIV/AIDS (Mental Health D&A Nurse) in a large not-for-profit district nursing organization providing care to people living with HIV/AIDS in an Australian city. Outcomes from a client assessment and 6-8-week follow-up by the Mental Health D&A Nurse are presented as captured by the Depression Anxiety Stress Scales (DASS 21), Alcohol, Smoking and Substance Involvement Screening Test (ASSIST), Health of the Nation Outcome Scales (HONOS) and WHOQoL BREF. Mean scores and caseness were analysed, and significant differences were found on the 'impairment' and 'social problems' subscales of the HONOS. Results of semi-structured interviews with clients describe effective and supportive mental health care and health-promoting education following visits by the Mental Health D&A Nurse. These positive findings support continuing implementation of the role within this community setting and indicate that even greater benefits will ensue as the role develops further. Findings are of interest to clinicians and policy makers seeking to implement similar roles in community-based HIV/AIDS care.


Subject(s)
Acquired Immunodeficiency Syndrome/nursing , Alcoholism/rehabilitation , Community Mental Health Services/standards , HIV Infections/nursing , Psychiatric Nursing/standards , Substance-Related Disorders/rehabilitation , Acquired Immunodeficiency Syndrome/complications , Adolescent , Adult , Alcoholism/complications , Alcoholism/nursing , Australia , Documentation , Health Promotion , Humans , Nursing Assessment , Patient Advocacy , Substance-Related Disorders/complications , Substance-Related Disorders/nursing
3.
J Intellect Disabil Res ; 46(Pt 1): 61-75, 2002 Jan.
Article in English | MEDLINE | ID: mdl-11851857

ABSTRACT

The present study assessed the reliability and validity of the revised scales of the Developmental Behaviour Checklist (DBC) in a Dutch sample of children with intellectual disability (ID). The psychometric properties of the parent and teacher versions of the DBC were assessed in various subsamples derived from a sample of 1057 Dutch children (age range=6-18 years) with ID or borderline intellectual functioning. Good test-retest reliability was shown both for the parent and teacher versions. Moderate inter-parent agreement and high one-year stability was found for the scale scores. Construct validity was satisfactory, although limited by high informant variance. The DBC scales showed good criterion-related validity, as indicated by significant mean differences between referred and non-referred children, and between children with and without a corresponding DSM-IV diagnosis. The reliability and validity of the revised DBC scales are satisfactory, and the checklist is recommended for clinical and research purposes.


Subject(s)
Child Behavior Disorders/diagnosis , Developmental Disabilities/diagnosis , Intellectual Disability/psychology , Adolescent , Analysis of Variance , Child , Disability Evaluation , Female , Humans , Intellectual Disability/epidemiology , Male , Netherlands/epidemiology , Psychiatric Status Rating Scales , Psychometrics , Reproducibility of Results
4.
Microsc Res Tech ; 52(3): 344-51, 2001 Feb 01.
Article in English | MEDLINE | ID: mdl-11180625

ABSTRACT

Recent progress in the field of electron cryo-microscopy and image analysis has shown that there is an overwhelming need to interpret medium resolution (5 to 10 A) three-dimensional maps. Traditional methods of fitting amino acid residues into electron density using molecular modeling programs must be supplemented with further analysis. We have used a potential of mean force (PMF) method, derived from Boltzmann statistics in protein structure, to generate models for the packing of alpha-helices, using pairwise potentials between amino acid residues. The approach was tested using the three-dimensional map of a recombinant cardiac gap junction membrane channel provided by electron cryo-crystallography (Unger et al., 1997; 1999a, 1999b) which had a resolution of 7.5 A in the membrane plane and 21 A in the vertical direction. The dodecameric channel was formed by the end-to-end docking of two hexamers, each of which displayed 24 rods of density in the membrane interior, which was consistent with an alpha-helical conformation for the four transmembrane domains of each connexin subunit. Based on the three-dimensional map and the amino acid sequence for the 4 transmembrane domains determined by hydropathy analysis, we used the modeling utility SymServ (Macke et al., 1998) to build hexameric connexons with 24 transmembrane alpha-helices. Canonical alpha-helices were aligned to the axes of the rods of density and translated along the density so that the center of masses coincided. The PMF function was used to evaluate 162,000 conformations for each of the 24 possible alpha-helical packing models. Since the different packing models yielded different energy distributions, the pair potential function appears to be a promising tool for evaluating the packing of alpha-helices in membrane proteins. The analysis will be refined by energy calculations based on the expectations that the outer boundary of the channel will be formed by hydrophobic residues in contact with the lipids.


Subject(s)
Connexins/chemistry , Gap Junctions/chemistry , Ion Channels/chemistry , Connexins/physiology , Cryoelectron Microscopy , Gap Junctions/ultrastructure , Ion Channel Gating , Models, Molecular , Protein Conformation , Protein Structure, Secondary
5.
Proc Natl Acad Sci U S A ; 97(13): 7112-7, 2000 Jun 20.
Article in English | MEDLINE | ID: mdl-10840061

ABSTRACT

The 30-kDa movement protein (MP) is essential for cell-cell spread of tobacco mosaic virus in planta. To explore the structural properties of MP, the full-length recombinant MP gene was expressed in Escherichia coli, and one-step purification from solubilized inclusion bodies was accomplished by using anion exchange chromatography. Soluble MP was maintained at >4 mg/ml without aggregation and displayed approximately 70% alpha-helical conformation in the presence of urea and SDS. A trypsin-resistant core domain of the MP had tightly folded tertiary structure, whereas 18 aa at the C terminus of the monomer were rapidly removed by trypsin. Two hydrophobic regions within the core were highly resistant to proteolysis. Based on results of CD spectroscopy, trypsin treatment, and MS, we propose a topological model in which MP has two putative alpha-helical transmembrane domains and a protease-sensitive carboxyl terminus.


Subject(s)
Membrane Proteins , RNA-Binding Proteins , Tobacco Mosaic Virus/genetics , Tobacco Mosaic Virus/metabolism , Viral Proteins , Amino Acid Sequence , Membrane Proteins/chemistry , Membrane Proteins/genetics , Membrane Proteins/metabolism , Molecular Sequence Data , Plant Viral Movement Proteins , Protein Folding , RNA-Binding Proteins/chemistry , RNA-Binding Proteins/genetics , RNA-Binding Proteins/metabolism , Recombinant Proteins/chemistry , Recombinant Proteins/genetics , Recombinant Proteins/metabolism , Viral Proteins/chemistry , Viral Proteins/genetics , Viral Proteins/metabolism
6.
Percept Mot Skills ; 89(2): 431-40, 1999 Oct.
Article in English | MEDLINE | ID: mdl-10597579

ABSTRACT

This study extended research examining Bandura's (1997) proposed model of collective efficacy. Specifically, it examined the relationships between groups' collective efficacy and the precompetitive anxiety and affect they experienced. Prior to a competitive match 66 male Rugby Union footballers from 6 teams (2 university teams and 4 county league teams) completed a single-item measure of confidence in their team winning the forthcoming match, a 10-item measure of confidence in their team performing well in the forthcoming match, the modified Competitive State Anxiety Inventory-2, and the Positive and Negative Affect Schedule. Stepwise (forward) multiple regression analyses indicated that scores for collective efficacy accounted for only 6.3% of the variance in the intensities of cognitive state anxiety and only 22% of the variance in the positive affect experienced prior to the rugby match. The results indicate that concerns with the team's ability to win a match were associated with high cognitive state anxiety and that doubts regarding the team's ability to perform well were related to low positive affect. Given the magnitude of predicted variances, the findings seem to give some support to Bandura's proposal that the beliefs in collective efficacy of individuals engaged in a team task are related to precompetitive affective reactions and the experience of state anxiety.


Subject(s)
Competitive Behavior/physiology , Football/physiology , Group Processes , Self Efficacy , Achievement , Adult , Football/psychology , Humans , Male , Models, Psychological , Motor Skills/physiology
7.
J Mol Biol ; 276(3): 591-602, 1998 Feb 27.
Article in English | MEDLINE | ID: mdl-9551099

ABSTRACT

The bacterial phosphoenolpyruvate-dependent phosphotransferase system (PTS) mediates both the uptake of carbohydrates across the cytoplasmic membrane and their phosphorylation. During this process, a phosphoryl group is transferred from phosphoenolpyruvate via the general PTS proteins enzyme I, HPr and the sugar-specific components IIA, IIB to the transported sugar. The crystal structure of the IIB subunit of a fructose transporter from Bacillus subtilis (IIBLev) was solved by MIRAS to a resolution of 2.9 A. IIBLev comprises 163 amino acid residues that are folded into an open, mainly parallel beta-sheet with helices packed on either face. The phosphorylation site (His15) is located on the first loop (1/A) at one of the topological switch-points of the fold. Despite different global folds, IIBLev and HPr have very similar active-site loop conformations with the active-site histidine residues located close to the N terminus of the first helix. This resemblance may be of functional importance, since both proteins exchange a phosphoryl group with the same IIA subunit. The structural basis of phosphoryl transfer from HPr to IIAMan to IIBMan was investigated by modeling of the respective transition state complexes using the known HPr and IIAMan structures and a homology model of IIBMan that was derived from the IIBLev structure. All three proteins contain a helix that appears to be suitable for stabilization of the phospho-histidine by dipole and H-bonding interactions. Smooth phosphoryl transfer from one N-cap position to the other appears feasible with a minimized transition state energy due to simultaneous interactions with the donor and the acceptor helix.


Subject(s)
Bacillus subtilis/enzymology , Membrane Transport Proteins/chemistry , Phosphoenolpyruvate Sugar Phosphotransferase System/chemistry , Protein Structure, Secondary , Amino Acid Sequence , Bacillus subtilis/genetics , Binding Sites , Crystallography, X-Ray , Escherichia coli/enzymology , Escherichia coli/genetics , Genetic Complementation Test , Histidine , Macromolecular Substances , Membrane Transport Proteins/genetics , Membrane Transport Proteins/metabolism , Models, Molecular , Monosaccharide Transport Proteins , Phosphoenolpyruvate Sugar Phosphotransferase System/genetics , Phosphoenolpyruvate Sugar Phosphotransferase System/metabolism , Phosphorylation
8.
Bull Menninger Clin ; 62(1): 96-111, 1998.
Article in English | MEDLINE | ID: mdl-9524381

ABSTRACT

Prinzmetal's angina, a form of angina precipitated by vasoconstriction or spasm, appears to be a somatic phenomenon, but there is evidence, from research and case reports, of a major psychological component. In this study, individuals with Prinzmetal's angina were interviewed to determine the nature of their interpersonal relationships and their intrapsychic state at the time of onset of their chest pain. In addition, short developmental histories were obtained. The authors found that onset of chest pain was related to experiencing intense affect, and multiple levels of interpersonal and intrapsychic conflict, with strong conscious and unconscious, emotional and ideational links to previous traumas.


Subject(s)
Angina Pectoris, Variant/psychology , Emotions , Psychoanalytic Interpretation , Psychophysiologic Disorders/psychology , Adult , Angina Pectoris, Variant/diagnosis , Arousal , Conflict, Psychological , Coronary Vasospasm/psychology , Female , Humans , Interpersonal Relations , Male , Middle Aged , Personality Assessment , Personality Development , Psychoanalytic Therapy , Psychophysiologic Disorders/diagnosis , Sick Role
9.
Br J Psychiatry ; 169(1): 27-9, 1996 Jul.
Article in English | MEDLINE | ID: mdl-8818364

ABSTRACT

BACKGROUND: The Bethlem Scale was designed as a validated measure of mother-infant adjustment in mother-baby units. METHOD: A multi-centre trial was conducted to investigate aspects of the reliability, validity and clinical usefulness of the Bethlem Mother-infant Interaction Scale within five in-patient psychiatric mother-baby units. RESULTS: This revealed good inter-rater, test-retest and inter-item reliability. Correlations of the scale items with psychiatrist's ratings and changes in scoring over time suggest reasonable validity, despite some design problems with individual items. CONCLUSION: Mother-infant interaction scales may have an important role in improving the quality of care for mothers and their babies in the psychiatric setting. The development of a more extensive scale, the Monash Mother-Infant interaction Scale, is discussed.


Subject(s)
Mental Disorders/psychology , Mother-Child Relations , Patient Admission , Personality Assessment/statistics & numerical data , Adult , Female , Humans , Infant , Maternal Behavior , Mental Disorders/diagnosis , Mental Disorders/therapy , Observer Variation , Psychiatric Department, Hospital , Psychometrics , Reproducibility of Results
10.
J Mol Biol ; 259(3): 502-11, 1996 Jun 14.
Article in English | MEDLINE | ID: mdl-8676384

ABSTRACT

The mannose transporter from Escherichia coli is a member of the phosphoenolpyruvate-dependent phosphotransferase system. The multi-subunit complex couples translocation across the bacterial inner membrane with phosphorylation of the solute. A functional fragment (IIA(Man), residues 2 to 133) of the membrane-associated IIAB(Man) subunit of the mannose transporter was expressed as a selenomethionine protein, and the unphosphorylated molecule was crystallized and its structure solved by X-ray crystallography. The protein consists of a central five-stranded beta-sheet covered by helices on either face. The order of the secondary structure elements is (beta alpha)4, alpha beta. Four beta-strands are arranged in a parallel manner with strand order 2134 and are linked by helices forming right-handed cross-over connections. The fifth strand that forms one edge of the sheet and runs antiparallel to the others is swapped between the subunits of the dimeric structure. Helices D and E form a helical hairpin. Histidine 10, which is transiently phosphorylated during catalysis, is located at the topological switch-point of the structure, close to the subunit interface. Its imidazole ring is hydrogen bonded to the buried side-chain of Asp67. It is likely that Asp67 acts as a general base and thus increases the nucleophilicity of the histidine. Modeling suggests that the covalently bound phosphoryl group would be stabilized by the macrodipole of helix C. Putative interactions between IIA(Man) and the histidine-containing phosphocarrier protein are discussed.


Subject(s)
Carrier Proteins/chemistry , Escherichia coli/chemistry , Mannose/metabolism , Phosphoenolpyruvate Sugar Phosphotransferase System/chemistry , Amino Acid Sequence , Binding Sites , Biological Transport , Carrier Proteins/metabolism , Crystallography, X-Ray , Escherichia coli/metabolism , Mannose/chemistry , Models, Molecular , Molecular Sequence Data , Phosphoenolpyruvate Sugar Phosphotransferase System/metabolism , Phosphorylation , Phosphotransferases/chemistry , Phosphotransferases/metabolism , Protein Conformation , Selenium , Sequence Homology, Amino Acid
11.
J Intellect Disabil Res ; 40 ( Pt 3): 198-207, 1996 Jun.
Article in English | MEDLINE | ID: mdl-8809661

ABSTRACT

The Developmental Behaviour Checklist (DBC) was developed to assess psychopathology in children with intellectual disabilities. A cut-off point between "non-cases' and "cases' was determined by comparison of the total scores with psychiatric clinical assessment. This paper describes a method aimed at determining the types of psychiatric problems in those regarded as "cases'. Factor analysis with varimax rotation carried out on a sample of 1093 subjects extracted six factors. Standardized factor scores were calculated for each subject in a community sample (n = 450), and the only or the dominant positive score was determined for each of the "cases'. Over 80% of "cases' could be allotted to one condition. Only a small number had none, or three or more conditions. The same procedure was replicated on a validation sample (n = 448) with even more satisfactory results. Differences in the prevalence of the six conditions by sex, age and level of mental retardation were ascertained. The validity and clinical relevance of this method are discussed.


Subject(s)
Intellectual Disability/diagnosis , Mental Disorders/diagnosis , Personality Assessment/statistics & numerical data , Adolescent , Antisocial Personality Disorder/diagnosis , Antisocial Personality Disorder/epidemiology , Antisocial Personality Disorder/psychology , Anxiety Disorders/diagnosis , Anxiety Disorders/epidemiology , Anxiety Disorders/psychology , Autistic Disorder/diagnosis , Autistic Disorder/epidemiology , Autistic Disorder/psychology , Child , Child Behavior Disorders/diagnosis , Child Behavior Disorders/epidemiology , Child Behavior Disorders/psychology , Child, Preschool , Comorbidity , Cross-Sectional Studies , Factor Analysis, Statistical , Female , Humans , Incidence , Intellectual Disability/epidemiology , Intellectual Disability/psychology , Language Development Disorders/diagnosis , Language Development Disorders/epidemiology , Language Development Disorders/psychology , Male , Mental Disorders/epidemiology , Mental Disorders/psychology , Psychiatric Status Rating Scales/statistics & numerical data , Psychometrics , Victoria/epidemiology
13.
J Am Acad Child Adolesc Psychiatry ; 33(8): 1194-202, 1994 Oct.
Article in English | MEDLINE | ID: mdl-7982870

ABSTRACT

OBJECTIVE: The Juvenile Fire Awareness and Intervention Program was established to develop and evaluate an intervention to be offered by fire fighters for children who set fires. METHOD: One hundred thirty-eight children, aged 5 to 16 years, with a history of firesetting participated in a randomized, controlled trial. The intervention involved education about fire safety and a behavior modification program designed to extinguish the desire to set fires through satiation. The frequency and severity of firesetting were recorded for 12 months after the intervention to measure outcome. RESULTS: There was a significant decrease in the frequency and severity of firesetting across all groups, with no additional improvement resulting from participation in the fire fighters' intervention. CONCLUSIONS: There is no evidence to suggest that the multicomponent program offered by trained fire fighters is effective in reducing firesetting. The marked reduction in firesetting across all groups suggests that fire safety education by the fire fighters is the most appropriate approach to this serious community problem.


Subject(s)
Behavior Therapy , Firesetting Behavior/prevention & control , Adolescent , Child , Child, Preschool , Female , Firesetting Behavior/psychology , Humans , Male , Personality Assessment , Safety , Satiation
14.
J Mol Biol ; 228(4): 1259-62, 1992 Dec 20.
Article in English | MEDLINE | ID: mdl-1474590

ABSTRACT

The LH1 light harvesting complex has been purified from a mutant of the photosynthetic bacterium Rhodobacter sphaeroides which synthesizes LH1 as the sole pigment protein. Crystallization trials using polyethylene glycol as the precipitant in the presence of the detergent n-octyl glucoside have resulted in the formation of needle like crystals which diffract beyond 3.5 A and which are relatively resistant to radiation damage. X-ray photographs have established that the crystals belong to the tetragonal system and are probably in space group P4(2)2(1)2. Estimates of the crystal density indicate that the asymmetric unit of the crystals contains two oligomers each with an alpha 6 beta 6 stoichiometry.


Subject(s)
Bacterial Proteins/chemistry , Membrane Proteins/chemistry , Photosynthetic Reaction Center Complex Proteins/chemistry , Rhodobacter sphaeroides/chemistry , Bacterial Proteins/isolation & purification , Crystallization , Glucosides , Membrane Proteins/isolation & purification , Photosynthesis , Polyethylene Glycols , X-Ray Diffraction
15.
Addict Behav ; 17(6): 579-85, 1992.
Article in English | MEDLINE | ID: mdl-1488938

ABSTRACT

This descriptive study monitored weight, Body Mass Index, and percent excess weight changes in 60 clients, (44 women, 16 men) at about 1 year and 2.5 years following participation in the Weight Control for Life! program. The program integrates the habit reversal treatment model with contingency management and operant reinforcement principles; nutrition education; physical activity; stress management; cognitive-restructuring; relapse prevention; social support; intensive, on-going maintenance; self-monitoring; and the use of a medically supervised very-low-calorie diet or low-calorie-diet. Clients' pretreatment and posttreatment weights averaged 104.28 kg (229.42 lb) and 79.89 kg (175.76 lb), respectively, representing a 68% reduction in excess body weight at the end of the weight loss phase of the program. Mean weight loss at about 1 year and 2.5 years post weight loss was 19.28 kg (42.42 lb) and 13.09 kg (28.80 lb), indicating subjects maintained 75% and 52% of their weight losses at these two time periods. Men lost more weight and maintained better losses than women. Overall, there was a 41% reduction in excess body weight at the end of 2.5 years.


Subject(s)
Body Mass Index , Body Weight , Adolescent , Aged , Female , Follow-Up Studies , Humans , Male , Middle Aged , Obesity , Sex Factors , Weight Loss
16.
Biophys J ; 58(4): 997-1009, 1990 Oct.
Article in English | MEDLINE | ID: mdl-2249000

ABSTRACT

Giant bilayer vesicles were reconstituted from several lipids and lipid/cholesterol (CHOL) mixtures: stearolyloleoylphosphatidylcholine (SOPC), bovine sphingomyelin (BSM), diarachidonylphosphatidylcholine (DAPC), SOPC/CHOL, BSM/CHOL, DAPC/CHOL, and extracted red blood cell (RBC) lipids with native cholesterol. Single-walled vesicles were manipulated by micropipette suction and several membrane material properties were determined. The properties measured were the elastic area compressibility modulus K, the critical areal strain alpha c, and the tensile strength tau lys, from which the failure energy or membrane toughness Tf was calculated. The elastic area expansion moduli for these lipid and lipid/cholesterol bilayers ranged from 57 dyn/cm for DAPC to 1,734 dyn/cm for BSM/CHOL. The SOPC/CHOL series and RBC lipids had intermediate values. The results indicated that the presence of cholesterol is the single most influential factor in increasing bilayer cohesion, but only for lipids where both chains are saturated, or mono- or diunsaturated. Multiple unsaturation in both lipid chains inhibits the condensing effect of cholesterol in bilayers. The SOPC/CHOL system was studied in more detail. The area expansion modulus showed a nonlinear increase with increasing cholesterol concentration up to a constant plateau, indicating a saturation limit for cholesterol in the bilayer phase of approximately 55 mol% CHOL. The membrane compressibility was modeled by a property-averaging composite theory involving two bilayer components, namely, uncomplexed lipid and a lipid/cholesterol complex of stoichiometry 1/1.22. The area expansion modulus of this molecular composite membrane was evaluated by a combination of the expansion moduli of each component scaled by their area fractions in the bilayer. Bilayer toughness, which is the energy stored in the bilayer at failure, showed a maximum value at approximately 40 mol% CHOL. This breakdown energy was found to be only a fraction of the available thermal energy, implying that many molecules (approximately 50-100) may be involved in forming the defect structure that leads to failure. The area expansion modulus of extracted RBC lipids with native cholesterol was compared with recent measurements of intact RBC membrane compressibility. The natural membrane was also modeled as a simple composite made up to a compressible lipid/cholesterol matrix containing relatively incompressible transmembrane proteins. It appears that the interaction of incompressible proteins with surrounding lipid confers enhanced compressibility on the composite structure.


Subject(s)
Cholesterol , Lipid Bilayers , Biophysical Phenomena , Biophysics , Cholesterol/chemistry , Elasticity , Erythrocyte Membrane/chemistry , Humans , In Vitro Techniques , Lipid Bilayers/chemistry , Membrane Lipids/chemistry , Tensile Strength , Thermodynamics
17.
Angiology ; 41(4): 253-62, 1990 Apr.
Article in English | MEDLINE | ID: mdl-2339824

ABSTRACT

Pentoxifylline is a methylxanthine derivative used to increase blood flow in peripheral atherosclerosis. Pentoxifylline is known to increase whole blood filtration rate, and recent evidence suggests that pentoxifylline increases the filtration rate of polymorphonuclear leukocytes (PMNs). The purpose of this study was to directly observe and quantitate the effect of pentoxifylline on the flow of individual PMNs into a model capillary. Short-term incubation of human PMNs with 10 mM pentoxifylline inhibited cell activation, as judged by a significant reduction in the number of neutrophils forming pseudopods. Furthermore, incubation of PMNs from 6 healthy men with 0.1, 1.0 and 10 mM pentoxifylline significantly decreased the time required for individual cells to be aspirated into a 4 microns pipet under constant pressure by 16 +/- 5%, 21 +/- 7%, and 41 +/- 8%, respectively (mean +/- SEM, p less than or equal to 0.05), compared with control. These experiments are the first direct demonstration of increased deformability in neutrophils treated with pentoxifylline. The results are consistent with the hypothesis that the beneficial effect of pentoxifylline on microvascular perfusion is partly due to an inhibition of PMN stiffness and activation.


Subject(s)
Neutrophils/drug effects , Pentoxifylline/pharmacology , Theobromine/analogs & derivatives , Adult , Capillaries/physiology , Humans , In Vitro Techniques , Male , Models, Cardiovascular , Neutrophils/physiology , Pseudopodia/drug effects
18.
J Cell Physiol ; 140(3): 549-57, 1989 Sep.
Article in English | MEDLINE | ID: mdl-2777892

ABSTRACT

Entry times for spherical (no pseudopods) polymorphonuclear leukocytes (PMNs) into a 4 microns micropipet have been measured as a function of pipet suction pressure (2,500-20,000 dyn/cm2) and concentration of the drug pentoxifylline (PTX, 0.1-10.0 mM). For control cells (0 mM PTX), entry rates (reciprocal entry times) increased almost linearly with increasing suction pressure, indicating a Newtonian-like behavior. With incubation in PTX solutions, entry rate vs. suction pressure became increasingly non-linear, suggesting a shear-thinning effect for the dissipative structure. At a given suction pressure the rate of entry showed a dose-dependent increase with increasing PTX concentration, the effect being most pronounced at high suction pressures (20,000 dyn/cm2). Also, with increasing PTX concentration two other effects were observed: i) there was a decreased incidence of cells that displayed pseudopodia, and ii) there was an increased incidence of cells forming hernias and an increased streaming of cell cytoplasm during aspiration. The first observation points to a down-regulation of the cell's functional ability to "activate" in response to surface/chemical stimuli, and the second indicates that both the cortical and cytoskeletal networks are weakened either by disruption and/or reduction in density of the protein polymers. These observations are in line with other recently published experiments which suggest that the rheological effects of pentoxifylline on PMNs may be associated with the state of actin.


Subject(s)
Neutrophils/drug effects , Pentoxifylline/pharmacology , Theobromine/analogs & derivatives , Actins/metabolism , Cell Survival/drug effects , Cytoskeleton/drug effects , Dose-Response Relationship, Drug , Humans , In Vitro Techniques , Neutrophils/physiology , Viscosity
20.
Skeletal Radiol ; 16(5): 383-6, 1987.
Article in English | MEDLINE | ID: mdl-3629282

ABSTRACT

The principal causes in children of a non-acute painful hip are Perthes disease and synovitis (irritable hip). The 99mTc methylene diphosphonate (MDP) bone scan appearances in Perthes disease are well-known; in synovitis, the hip may show a diffuse increase in activity or may be normal. The significance of bone scintigraphy in the clinical setting of non-acute hip symptoms with normal skeletal radiography has been evaluated in 36 symptomatic children. The mean duration of symptoms prior to scan was 3 months (range 1 week-17 months). On the basis of final diagnosis, established by clinical findings, bone scan, X-ray and follow-up, the children were divided into two groups: synovitis or Perthes disease. Of the 33 scans in the 32 children with synovitis, 18 were normal and 15 showed diffusely increased activity on the painful side. All four patients with Perthes disease had focal femoral head abnormalities in the painful hip. Of the 18 children with normal scans, none went on to develop a skeletal disorder. In children with hip pain of over 1 week's duration, the main value of the bone scan is the early detection of Perthes disease. Diffuse increased activity on the painful side suggests synovitis. A normal scan virtually excludes significant skeletal abnormality.


Subject(s)
Hip Joint/diagnostic imaging , Pain/etiology , Child , Child, Preschool , Female , Humans , Legg-Calve-Perthes Disease/complications , Legg-Calve-Perthes Disease/diagnostic imaging , Male , Radiography , Radionuclide Imaging , Synovitis/complications , Synovitis/diagnostic imaging , Technetium Tc 99m Medronate
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