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Biomedical subjects

M Green

Publications and source records attributed to M Green.

At least 73 records · Page 4Linked to original sources
PubMed2001

Exploring the impact of physician verbal abuse on perioperative nurses.

The purpose of this study is to explore the incidence and impact of physician verbal abuse on perioperative nurses. Roy's Adaptation Model was used as the framework for this descriptive, exploratory study. Seventy-eight perioperative nurses completed the Verbal Abuse Scale questionnaire. Seventy-one nurses (91%) reported experiencing some type of verbal abuse from a physician during the past year. Results show, however, that nurses use adaptive coping behaviors and problem-focused skills to deal with the abuse.

Adaptation, Psychological↗
PubMed2001

Chalk as the carrier for nitrifying biofilm in a fluidized bed reactor.

A fluidized bed reactor for nitrification with chalk as the biomass carrier and the sole buffer agent was studied. Chalk dissolution in the reactor was found to follow the stoichiometric ratio of 1 mole of CaCO3 dissolved for each mole of NH4+ oxidized. Three batches of chalk, each one having a different dissolution rate, were used to replace the dissolved chalk. The three dissolution rates resulted in three different steady state pH levels in the reactor (4.7-6.6) and nitrification rates. Nitrification was found to be limited by either the chalk dissolution rate or dissolved oxygen concentration depending on the type of chalk used. A maximal nitrification rate of 1.44 g NH4(+)-N/l reactor.d was observed. The average cell yield was 0.1 g cells/g N oxidized, similar to the cell yield during reactor start-up when the pH was 7. The specific ammonium oxidation rates varied between 0.08 and 0.15 mg NH4(+)-N oxidized/mg protein.h, values which are in the reported range for nitrification at pH 7 to 8. Oxygen update rate (OUR) results indicated that the major mechanism responsible for the high nitrification rate observed in the reactor operating at low pH seems to be the favorable microenvironment provided by the chalk.

Bacteria↗
PubMed2001

Ammonium removal using a novel unsaturated flow biological filter with passive aeration.

A novel vertical bed process for the removal of ammonium from secondary effluents, using a "passive air pump", has been developed. The process is based on convective aeration caused by a fill and draw operational sequence, and combines the advantages of the vertical wetlands concept with the high loading rates typically associated with trickling filters. Experiments were carried out in a 500-l reactor using simulative effluents and actual municipal secondary effluents. A maximal ammonium removal rate of 1100 g N/m2 reactor/d was achieved using simulative effluents and an effective gravel size of 0.96 mm. At all hydraulic loads applied, the nitrification rate was found to be limited by the oxygen transfer rate. The small-size medium used with simulative effluents clogged when using actual municipal secondary effluents. Two other media (2.46 mm and 4.31 mm) did not clog during the entire experimental period and a maximum removal load of 300 g N/m2 reactor/d was achieved. This value is still much higher than typical rates reported for conventional vertical beds.

Filtration↗
PubMed2001

Atrazine degradation under denitrifying conditions in continuous culture of Pseudomonas ADP.

The simultaneous removal of atrazine and nitrate in continuous culture under denitrifying conditions using Pseudomonas sp. strain ADP was investigated. Under all operational conditions the nitrate removal efficiency was always higher than 90%, while atrazine degradation deteriorated with time due to contamination by foreign denitrifying bacteria, lacking the ability to degrade atrazine. Recovery of atrazine degradation ability was achieved by applying aerobic conditions with atrazine as the sole nitrogen source.

Aerobiosis↗
PubMed2001

Molecular cloning of a novel isoform of diphosphoinositol polyphosphate phosphohydrolase: a potential target of lithium therapy.

The mechanisms underlying the therapeutic effects of lithium are largely unknown but may involve progressive adaptive alterations at the level of gene expression. Using differential display PCR, we identify a novel cDNA fragment, the expression of which was increased in the rat frontal cortex after 5 weeks of lithium administration. A full-length cDNA (2954-nt) was cloned by arrayed cDNA library screening, and sequencing of the clone revealed an open reading frame of 537-bp encoding a 179-residue protein. Amino acid sequence comparisons revealed that our clone is a member of the Nudix hydrolase family, with the highest percentage of homology (95%) being with a subtype of human diphosphoinositol polyphosphate phosphohydrolase, hDIPP2. Northern blot analysis revealed that chronic lithium treatment significantly increased rDIPP2 mRNA levels in frontal cortex, but not in hippocampus, midbrain, and cerebellum. The effect of lithium on rDIPP2 mRNA expression was not shared by two other anticonvulsant mood stabilizers, carbamazepine and valproate. Time-course studies showed that 1-week of lithium had no effect on rDIPP2 mRNA abundance in the frontal cortex. Our results suggest that DIPP2 may represent a biologically relevant target of lithium therapy, further supporting the notion that abnormalities in inositol phosphate metabolism may be significant in the pathophysiology and pharmacotherapy of bipolar disorder.

Acid Anhydride Hydrolases↗
PubMed2001

Tetraspan protein CD151: a common target of mood stabilizing drugs?

The latency in onset of antimanic and mood stabilizing effects of lithium suggest that long-term neuronal adaptations mediated by changes in gene expression may be important to the therapeutic action of lithium treatment. Using differential display-polymerase chain reaction, several novel, hitherto unexpected lithium-regulated genes have been isolated, all of which would not have been predicted with the candidate gene approach. During the process of characterizing one of these novel genes, we have identified a cDNA clone, a homolog of human/mouse transmembrane-4-superfamily (also known as tetraspan) protein, CD151, the expression of which was significantly decreased in rat frontal cortex following chronic (five weeks) lithium treatment. The reduction of CD151 mRNA levels was also observed following chronic administration of carbamazepine and valproate. Conversely, the expression of CD151 was not altered by short-term (one week) lithium treatment and by chronic administration of the tricyclic antidepressant, imipramine, or the typical antipsychotic, haloperidol, further demonstrating time dependence and pharmacological specificity of this effect. Our studies, thus, indicate that CD151 may represent a therapeutically relevant target common to lithium and the anticonvulsant mood stabilizing drugs, carbamazepine and valproate.

Affect↗
PubMed2001

Pressure sores in intensive care: defining their incidence and associated factors and assessing the utility of two pressure sore risk assessment tools.

Patients in intensive care units (ICU) are at high risk of developing pressure sores and the use of pressure sore risk tools has been advocated as a means of identifying patients at risk. A prospective multi-site observational study was conducted to define the incidence of pressure sores, assess two pressure sore risk scales and to define risk factors relevant to intensive care. Patients (n = 534) were assessed for the presence of pressure sores. The Waterlow and Jackson/Cubbin risk scales were completed each day for 314 and 188 of these patients respectively. A total of 75 pressure sores were recorded. Of these, 34 were present on admission. Of the remaining 41, 16 were classified as Grade 1 and 24 as Grade 2 sores. The pressure sore (PS) incidence was 5.2 per cent. Expressed as PS/1000 patient days there were 18.48 pressure sores per 1000 patient days. The ability of the risk scores to predict pressure sores was tested using a Receiver Operating Characteristic (ROC) analysis. The association of risk score with pressure sores was analysed using a survival function (Kaplan Meier) and variables compared using a logrank test (Mantel-Cox). Factors associated with pressure sore occurrence were developed and tested using a survival regression model. Both risk scales were poor predictors of pressure sores (ROC curve area approximately 70 per cent for both). The factors, coma/unresponsiveness/paralysed & sedated and cardiovascular instability were significantly associated with pressure sores with relative risks of 4.2 and 2.5 respectively. Risk increased as a function of time such that the cumulative risk was 50 per cent at 20 days.

Adolescent↗
PubMed2001

Opposite effects of lithium on proximal and distal caspases of immature and mature primary neurons correlate with earlier paradoxical actions on viability.

To provide an explanation for earlier paradoxical findings of lithium on survival of mature and immature neurons, this study monitors changes in cytosolic caspases in rat cerebellar granule cells (CGC) grown 2-7 days in vitro (DIV), or in murine E-17 cortical neurons. Data show Li+ protects mature 7-DIV CGC parallel to a decrease in proximal and distal caspases but increases levels for immature 2-DIV-CGC or E-17 cortical neurons. Caspases mirror viability based on morphological analyses (dye uptake, phase-contrast, DNA fragmentation), and suggest protection occurs by suppressing activation of a cascade resulting in distal effectors that destroy proteins essential for neuronal survival. Protection was dose-dependent with EC50 3.0 mM and extended to 64 h in K+-serum deprived apoptotic media. Neuronal extracts contain a spectrum of proximal (-2, -8, -9) and distal (-3, -6) caspases sensitive to Li+ on assay with preferred peptide substrates and by immunoblotting. The lack of direct effect on activated cytosols indicates Li+ acts upstream only on intact cells, at sites for recruitment of pivotal procaspases. Alterations of procaspase-9 p46 and membrane-bound cytochrome c (Apaf-1) point to interaction with an intrinsic Mt-mediated pathway as one of the targets. The opposite effects on caspases and viability of immature or embryological neurons point to existence of alternative pathways that alter during neurite outgrowth suggesting the use of Li+ as a probe to unravel events relevant to neurogenesis.

Animals↗
PubMed2001

The risk for congenital heart defects in offspring of individuals with congenital heart defects.

BACKGROUND: Congenital heart defects (CHDs) occur in approximately 1% of all live births. Although most CHDs are of unknown etiology, a family history of CHDs is a known risk factor, and offspring of individuals with CHDs are at a higher risk of having CHDs. The aim of this study was to investigate the relative risk for CHDs to offspring of individuals with CHDs. METHODS: The prevalence rates of CHDs in offspring of 203 individuals with CHDs and 282 individuals without CHDs were investigated. The study participants completed a questionnaire that included information on medical and reproductive history, lifestyle indicators, and family history of CHDs and other congenital malformations. The prevalence rates of CHDs in offspring were calculated. RESULTS: The prevalence of CHDs was 3.1% (18/575) in offspring of individuals with CHDs and 1.3% (8/589) in offspring of individuals without CHDs. The adjusted odds ratio for CHDs to offspring of parents with CHDs was 1.73 (95% confidence interval [95% CI] 0.89-2.44, p=0.02). The estimated relative risk for offspring to females with CHD was higher than for males [2.3 (95% CI 1.1-4.7, p=0.03) versus 1.31 (95% CI 0.48-4.30, p=0.66), respectively]. There was no suggestion of association between CHDs and maternal smoking, alcohol consumption, and use of medication during pregnancy. CONCLUSIONS: Offspring of parents with CHDs are at a higher risk for CHDs compared with the general population. Couples where one member is affected with CHD should receive pre-conceptional or pre-natal genetic counseling and should be informed about the magnitude of the potential risk of CHDs to the offspring.

Family Health↗
PubMed2001

Primary tacrolimus (FK506) therapy and the long-term risk of post-transplant lymphoproliferative disease in pediatric liver transplant recipients.

While the overall incidence of post-transplant lymphoproliferative disease (PTLD) in pediatric liver transplant recipients has been reported to be 4-11%, the long-term risk of PTLD associated with primary tacrolimus therapy is unknown. Therefore, in order to determine the incidence and long-term risk of PTLD, the present study examined 131 pediatric recipients who underwent liver transplantation (LTx) between October 1989 and December 1991 and received primary tacrolimus therapy. This cohort of children was evaluated over an extended time-period (until December 31 1996) with a mean follow-up of 6.3 yr. Actuarial Kaplan-Meier analysis was utilized to determine the risk of PTLD over time. The overall incidence of PTLD was 13% (17/131) with an average age of 4.3 +/- 0.75 yr at diagnosis. Pretransplant Epstein-Barr virus (EBV) serologies were negative in 82%, positive in 12%, and not available in 6% of the patients. The median time to diagnosis of PTLD post-Tx was 11.9 months (mean 16.4 +/- 3.9, range 1.7-63.0 months). Mean tacrolimus dose and plasma trough level (as evaluated by enzyme-linked immunosorbent assay [ELISA]) at the time of diagnosis was 0.32 +/- 0.06 mg/kg/day and 1.3 +/- 0.3 ng/mL, respectively. The cumulative long-term risk of PTLD was found to increase over time: 3% at 6 months, 8% at 1 yr, 12% at 2 yr, 14% at 3 yr, and 15% at 4 and 5 yr. Mortality from PTLD was 12% (two of 17 patients). Primary tacrolimus use in pediatric LTx has a long-term risk of PTLD approaching 15%, with the majority of episodes (78%) occurring in the first 2 yr, suggesting that intense EBV surveillance should occur early post-transplantation.

Adolescent↗
PubMed2001

Epstein-Barr virus load monitoring: its role in the prevention and management of post-transplant lymphoproliferative disease.

The Epstein-Barr virus load in the peripheral blood at the time of diagnosis of post-transplant lymphoproliferative disease (PTLD) is elevated 1000- to 10,000-fold compared to the level detected in normal latency. With the use of quantitative polymerase chain reaction (PCR), changes in the viral load over time can be measured with a two- to fourfold accuracy. This has allowed early detection of first-time infections and reactivations that may lead to PTLD and has provided an opportunity to intervene before symptomatic disease has occurred. Viral load monitoring has also been used to follow patients with PTLD and, along with other parameters, provided an assessment of the effectiveness of therapeutic protocols. Viral load monitoring has led to the discovery that at least two-thirds of transplant recipients become persistent viral load carriers. While the persistent load appears to be largely carried in latently infected memory B cells, more work is needed to clearly define this type of persistent infection and determine the risks associated with it. New diagnostic tests need to be developed to distinguish the persistent latent viral loads from viral loads that are likely to become symptomatic PTLD.

DNA, Viral↗
PubMed2001

The role of antiviral and immunoglobulin therapy in the prevention of Epstein-Barr virus infection and post-transplant lymphoproliferative disease following solid organ transplantation.

The recognition of the importance of Epstein-Barr virus (EBV) infection, including EBV-associated post-transplant lymphoproliferative disease (PTLD), has led to a new focus on the prevention of this problem. This paper reviews the scientific rationale behind, and clinical experience with, the use of chemoprophylaxis (using acyclovir or ganciclovir) and immunoprophylaxis (using intravenous immunoglobulin) in the prevention of EBV/PTLD. While some centers have already introduced the use of one or both of these agents as standard prophylaxis against the development of this complication, published data in support of these protocols are currently lacking. Well designed clinical trials are necessary to evaluate the potential role of both antiviral and immunoglobulin agents in the prevention of EBV/PTLD in organ transplant recipients.

Antiviral Agents↗
PubMed2001

Audit and comprehensive health assessment programme in the primary healthcare of adults with intellectual disability: a pilot study.

International research has demonstrated significant shortcomings in the health of adults with intellectual disability (ID). Because general practitioners (GPs) are the main providers of primary healthcare for this population, strategies to improve general practice care are an important aspect of rectifying these shortcomings. The present pilot study aimed to determine the effect of various interventions on health maintenance activities and to assess their acceptability to GPs, with a view to informing larger scale studies. The GPs were recruited through an earlier questionnaire-based postal survey. The GPs identified all their adult patients with ID, then obtained consent for participation from three patients randomly selected by the investigators. The GPs completed two self-evaluation forms and case note audits 12 months apart, read a synopsis of the relevant literature provided by the researchers, and completed a comprehensive health assessment (CHA) of their three patients. Forty-five GPs agreed to participate in the CHA programme (CHAP), and 15 completed the project. Thirty-eight patients completed the project. The number of patient-GP dyads who completed the project was too small to demonstrate statistically significant changes in health issues over time. The GPs found that the synopsis of the literature was the best intervention for increasing knowledge and was also the most practical to use in general practice. The CHAP was the intervention that prompted the most action from the GP which would not have been undertaken otherwise. The CHAP appeared to provide a superior review process compared to the other interventions used in the present study. The numbers of health maintenance activities found to be overdue and the number of health issues detected as a result of the process were considerable. The CHAP served as a communication tool and an educative instrument, providing a basis for future studies and strategies to improve the general practice care of adults with ID.

Adult↗
PubMed2001

Tracheal tube pressure change during magnetic stimulation of the phrenic nerves as an indicator of diaphragm strength on the intensive care unit.

Diaphragm strength can be assessed from twitch gastric (TwPgas), twitch oesophageal (TwPoes), and twitch transdiaphragmatic pressure (TwPdi) in response to phrenic nerve stimulation. This requires the passage of balloon catheters, which may be difficult. Changes in pressure measured at the mouth during phrenic nerve stimulation avoid the need for balloon catheters. We hypothesized that pressures measured at the tracheal tube during phrenic stimulation, could also reflect oesophageal pressure change as a result of isolated diaphragmatic contraction and, therefore, reflect diaphragm strength. We aimed to establish the relationship between twitch tracheal tube pressure (TwPet), TwPoes, and TwPdi in patients in the supine and sitting positions. The phrenic nerves were stimulated magnetically bilaterally, in 14 ICU patients while supine and on another occasion while sitting up at 45 degrees. In the sitting position mean TwPoes was 9.1 cm H2O and TwPet 11.3 cm H2O (mean(SD) difference -2.2 (SD 1.5)). In the supine position mean TwPoes was 8.1 cm H2O and TwPet 9.9 cm H2O (mean difference -1.8 (2.2)). The difference between TwPoes and TwPet was less at low twitch amplitude; less than +/- 1 cm H2O below a mean twitch height of 8 cm H2O supine and 10 cm H2O sitting. Sitting TwPet was related to TwPoes r2=0.93 and TwPdi r2=0.65 (P<0.01). Supine TwPet was related to TwPoes r2=0.84 and TwPdi r2=0.83 (P<0.01). The mean within occasion coefficient of variation while sitting was TwPet=13.3%, TwPoes=13.9%, TwPdi=11.2%, and supine TwPet=11.6%, TwPoes=14.6%, TwPdi=11.8%. We conclude that TwPet reflects TwPoes during diaphragmatic stimulation and is worthy of further study to establish its place as a guide to the presence of respiratory muscle strength and fatigue.

Aged↗
PubMed2001

The role of gown and glove isolation and strict handwashing in the reduction of nosocomial infection in children with solid organ transplantation.

OBJECTIVE: Nosocomial infection is an important contributor to morbidity and mortality in pediatric solid organ transplantation. The relative effect of protective gown and glove isolation was compared with strict handwashing in pediatric intensive care unit (PICU) patients with solid organ transplantation. DESIGN/SETTING: A prospective, randomized design was used; children in a 23-bed PICU with solid organ transplantation were enrolled into a gown and glove protective isolation protocol or a strict handwashing protocol. PATIENTS: All children admitted to the PICU immediately after solid organ transplantation, excluding renal transplantation, and at subsequent readmissions to the PICU were eligible for the study. Children with current infection or known exposure to varicella were excluded from the study initially or at readmission. INTERVENTIONS: By using a block randomization design based on organ transplanted, age, and initial admission vs. readmission, each patient was randomized to either strict handwashing or protective gown and glove isolation intervention groups. MEASUREMENTS: We analyzed demographics, infection outcomes (defined according to Centers for Disease Control criteria), and monitoring of patient contacts in compliance with protocols. RESULTS: The infection rate in the overall PICU population did not change significantly from the year before the study compared with during the study (2.1 per 100 vs. 1.95 per 100 patient days; p =.4) The infection rate in the gown and glove group (2.3 per 100 patient days) was reduced significantly compared with the prestudy infection rate in the transplant population (4.9 per 100 patient days; p =.0008). Strict handwashing also significantly reduced the infection rate in the transplant population (3.0 per 100 patient days; p =.008). Compliance with gowning and gloving was 82% and compliance with handwashing was 76% (compared with 22% before study [p <.0001] and 52% after the study [p <.0001]). Despite an increased mean length of stay in the PICU in the gown and glove group (p =.014), there was a trend toward reduction in the incidence of infection (Fisher's exact test, p =.07; odds ratio,.76) in the gown and glove group. CONCLUSIONS: Increased compliance with handwashing was associated with a reduction in nosocomial infections, and gown and glove isolation appeared to have an additional protective effect. Some nosocomial infections may be preventable in the pediatric solid organ transplantation population.

Child↗
PubMed2001

Measurement of twitch transdiaphragmatic, esophageal, and endotracheal tube pressure with bilateral anterolateral magnetic phrenic nerve stimulation in patients in the intensive care unit.

OBJECTIVE: In the critically ill, respiratory muscle strength usually has been assessed by measuring maximum inspiratory pressure. The maneuver is volitional, and results can be unreliable. The nonvolitional technique of bilateral anterolateral magnetic stimulation of the phrenic nerves, producing twitch transdiaphragmatic pressure, has been successful in normal subjects and ambulatory patients. In this study we used the technique in the intensive care unit and explored the measurement of twitch endotracheal tube pressure as a less invasive technique to assess diaphragmatic contractility. DESIGN: Clinical study to quantify diaphragm strength in the intensive care unit. SETTING: Patients from three London teaching hospital intensive care units and high-dependency units. PATIENTS: Forty-one intensive care patients were recruited. Of these, 33 (20 men, 13 women) were studied. INTERVENTIONS: Esophageal and gastric balloon catheters were passed through the anaesthetized nose, and an endotracheal tube occlusion device was placed in the ventilation circuit, next to the endotracheal tube. Two 43-mm magnetic coils were placed anteriorly on the patient's neck, and the phrenic nerves were stimulated magnetically. MEASUREMENTS AND MAIN RESULTS: On phrenic nerve stimulation, twitch gastric pressure, twitch esophageal pressure, twitch transdiaphragmatic pressure, and twitch endotracheal tube pressure were measured. Forty-one consecutive patients consented to take part in the study, and twitch pressure data were obtained in 33 of these. Mean transdiaphragmatic pressure was 10.7 cm H2O, mean twitch esophageal pressure was 6.7 cm H2O, and mean twitch endotracheal tube pressure was 6.7 cm H2O. The mean difference between twitch esophageal pressure and twitch endotracheal tube pressure was 0.02 cm H2O. Correlation of the means of twitch endotracheal tube pressure to twitch esophageal pressure was 0.93, and that for twitch endotracheal tube pressure to transdiaphragmatic pressure was 0.78. CONCLUSIONS: Transdiaphragmatic pressure can be measured in the critically ill to give a nonvolitional assessment of diaphragm contractility, but not all patients can be studied. At present, the relationship of twitch endotracheal tube pressure to transdiaphragmatic pressure is too variable to reliably represent a less invasive measure of diaphragm strength.

Adult↗
PubMed2001

Lung and liver injury following hepatic ischemia/reperfusion in the rat is increased by exogenous lipopolysaccharide which also increases hepatic TNF production in vivo and in vitro.

Hepatic ischemia/reperfusion (I/R) results in tumor necrosis factor (TNF) release. Kupffer cells (KC) are one source of this TNF. This study investigates the effects of hepatic I/R combined with lipopolysaccharide (LPS) on the lung and liver injury that follow hepatic I/R and on hepatic release of TNF, epithelial neutrophil activating protein (ENA-78), and macrophage inflammatory protein-2 (MIP-2). The effects of these experimental conditions on TNF production by primary rat KC in vitro were also investigated. Rats were subjected to hepatic I/R alone, hepatic I/R + LPS, sham laparotomy alone, or sham laparotomy + LPS and pulmonary MPO, pulmonary microvascular permeability, hepatic neutrophil influx, hepatic injury, and hepatic TNF, ENA-78, and MIP-2 production were measured. These experiments demonstrated that hepatic I/R in conjunction with LPS results in a more severe lung and liver injury and increased hepatic TNF, ENA-78, and MIP-2 release. The effects of these experimental conditions on rat KC TNF production demonstrated that hepatic I/R + LPS results in a more significant release of TNF as compared to LPS alone or I/R alone. Hepatic I/R plus LPS results in a more severe lung and liver injury and is likely secondary to a more significant and prolonged release of TNF by KC. This may provide a mechanism for development of multiple organ system failure in some patients undergoing hepatic resection, hepatic transplantation, complex vascular operations, or in the setting of hypovolemic shock. Portal endotoxemia related to mesenteric venous congestion or other systemic insults may have a significant impact on post-operative complications and recovery in the setting of a local or global hepatic I/R injury.

Animals↗