Biomedical subjects

S Nelson

Publications and source records attributed to S Nelson.

At least 19 recordsLinked to original sources

PubMed2007

5-20: a model of minimum nurse-to-patient ratios in Victoria, Australia.

AIM: This study presents a critique of a new model of minimum nurse-to-patient ratio and considers its utility alongside established Patient Dependency Systems. BACKGROUND: Since 2001 legislation mandating minimum nurse-to-patient ratios has been enacted throughout large public hospitals in the state of Victoria, Australia. The Victorian model mandates minimum staffing of five nurses to 20 patients in acute medical and surgical wards. In conjunction with this approach, Patient Dependency Systems are employed to anticipate short-term resource needs. KEY ISSUES: Although this legislation has been successful in attracting nurses back into the public sector workforce, no published empirical evidence exists to support specific ratios. In addition, neither ratio nor Patient Dependency Systems approaches account for the critical influence of skill mix on hospital, employee, or patient outcomes. CONCLUSION: There is an urgent need for further research that specifically examines relationships between models of staffing, skill mix and quality outcomes.

Activities of Daily Living↗

PubMed2006

Clear not simple: an approach to community consultation for a maternal pneumococcal vaccine trial among Indigenous women in the Northern Territory of Australia.

PneuMum is a randomised controlled maternal vaccination trial, using 23-valent Pneumococcal Polysaccharide Vaccine (23vPPV) during the third trimester or at delivery compared to vaccination at 7 months post delivery. The primary outcomes are infant middle ear disease and nasopharyngeal pneumococcal carriage at 7 months of age. PneuMum is the first vaccine trial to be conducted among Indigenous people in the Northern Territory. We describe the study design and the approach taken to develop the PneuMum message in collaboration with key Indigenous stakeholders and then to communicate the PneuMum message with Indigenous communities and potential participants. We hope that these methods will provide a model for future research involving Indigenous communities to ensure Indigenous involvement in research and ultimate improvements in Indigenous health.

Adolescent↗

PubMed2006

The effects of alcohol on immunity and bacterial infection in the lung.

When faced with invading pathogens that can lead to infection, patients must mount an effective and appropriate immune response. Altered immune function in patients who abuse alcohol has long been described in the medical literature. The alcohol-consuming host is particularly prone to infections in the lung, including bacterial pneumonia and tuberculosis. Over the last several decades, there has been increased interest in the immune mechanisms that underlie the increased risk of infection observed in this population. This article will review the basic immunology involved in the host response to an infection and then describe how alcohol disrupts many of these immune mechanisms. It will further provide an overview of lung infections which have been linked to alcohol abuse, and finally, it will address the evolving therapeutic approaches of the immune system that are being advanced to assist in caring for immunosuppressed hosts.

Alcohol Drinking↗

PubMed2006

Relationship of degenerative changes of the temporomandibular joint (TMJ) with the angle of eminentia.

The purposes of this study were threefold: (i) to assess the degenerative changes of the temporomandibular joint [TMJ (condyles and articular eminence of the glenoid fossa)], (ii) to determine whether the TMJ degeneration levels differ by ethnic group and gender and (iii) to assess the association between the angles of eminentia and TMJ degeneration, while controlling for gender, ethnicity, age and number of teeth. The sample included 245 20th century dry skulls: 130 African-American (82 male and 48 female) and 115 European-American (75 male and 40 female), with a mean age of 46.4 +/- 19.9 years. The angles of eminentia were measured in a sagittal plane. The medial, central and lateral portions of the articular slope and anterior portion of the condyle were assessed for degenerative changes. Degeneration scores were calculated for the eminentia and condyles. Statistical analyses included two-way anovas, Pearson's correlation coefficients and linear regression models. There were differences in the degree of TMJ degeneration of the African-American and European-American males and females. European-American females retained fewer teeth, had the highest TMJ degeneration scores and exhibited significant relationships between the eminentia angles and degeneration. When the independent variables were entered into the regression model, only the degeneration of the eminentia was significantly associated with the angles of eminentia. Although the degeneration of the eminentia explained some of the variation of the eminentia angles, it is clear that the inclusion of multiple factors is essential to study the remodelling of the glenoid fossa.

Black or African American↗

PubMed2006

Asymmetry of the articular eminence in dentate and partially edentulous populations.

The purpose of this study was to assess the degree of right-left asymmetry of the glenoid fossa. The specific aims were (1) to determine whether there were relationships between age, number of teeth, slope of the articular eminence, fossa depth, and the degree of right-left asymmetry, and (2) to compare the right-left asymmetry of two populations, one characterized by an acceptable occlusion (A-Occ), the other by an unacceptable occlusion (partially edentulous; Un-Occ). A-Occ was defined as possessing a minimum of 28 teeth that would allow for hand articulation of the mandibular teeth to the maxillary teeth. Un-Occ had fewer than 17 teeth, which would make it impossible to articulate the mandible with the maxilla. The sample included 20th century dry skulls: 70 African-American (44 male, 26 female) and 64 European-American (49 male, 15 female), ranging in age from 21-105 (mean 47.1 +/- 19.9). The medial (M), central (C), and lateral (Lat) aspects of the right (R) and left (L) slopes of the articular eminence were measured in a sagittal plane. The R and L fossa depth also were measured. The raw absolute differences IR-LI and relative differences [IR-LI/IR+Llx100] of the articular slope angles (M, C, and Lat) and fossa depths were computed. Statistical analysis included paired t-tests, independent t-tests, and Pearson's correlation coefficients, significance at p < or = 0.05. Ninety percent (90%) of the population exhibited right-left asymmetry of the glenoid fossa. The right articular slopes (M, C, and Lat) were significantly steeper than the left articular slopes; the right fossa depths were significantly deeper than the left. There generally were no differences in the articular slope steepness or fossa depths between the partially dentate and the dentate, nor were there statistical differences between the two groups in the raw absolute differences or relative differences of the M, C, and Lat slopes or fossa depths. No significant relationships were found between right-left asymmetry, age, or number of teeth. With only 10% of the subjects exhibiting symmetry of the glenoid fossa depths or articular slope angles, clinicians should consider bilateral asymmetry the norm and not an anomaly.

Adult↗

PubMed2005

Human beta-defensins: differential activity against candidal species and regulation by Candida albicans.

Oral epithelial cell-derived human beta-defensins-1, -2, and -3 participate in innate immune responses against Candida. We hypothesized that these peptides utilize several mechanisms for protection. Recombinant hBD-1 and -2 were produced with the use of an insect cell/baculovirus expression system, while rhBD-3 was expressed as a fusion protein in E. coli. RhBD-2 and -3 were more effective at killing the candidal species at low micromolar concentrations than was rhBD-1, except for C. glabrata. While this species was relatively resistant to rhBD fungicidal activity, its adherence to oral epithelial cells was strain-specifically inhibited by the rhBDs. C. albicans hyphae were important in regulating hBD2 and -3 mRNA expression in primary human oral epithelial cells. Confocal microscopy of rhBD-2-challenged C. albicans suggests disruption of the fungal membrane. Results support the hypothesis that hBDs control fungal colonization through hyphal induction, direct fungicidal activity, and inhibition of candidal adherence.

Anti-Infective Agents↗

PubMed2004

Development and aging of N-methyl-D-aspartate receptor expression in the prefrontal/frontal cortex of mice.

The present study was designed to determine whether the changes that occur during aging in the expression of the N-methyl-D-aspartate (NMDA) receptor and two NMDA receptor subunits, zeta1 and epsilon2, are a continuation of developmental processes and whether protein and mRNA expression patterns of the subunits are similar across the lifespan. The prefrontal/frontal cortex of C57BL/6 mice of eight different ages (7-8, 13-15, 30-32, 49-53, and 70-72 days and 4.5, 11, and 25 months of age) were used to examine NMDA-displaceable [(3)H]glutamate binding and mRNA in tissue sections and mRNA and protein from homogenates. The lateral prefrontal/frontal cortex of C57BL/6 mice showed more significant declines in density of agonist binding to NMDA receptors during both development and aging than the medial cortex. Changes in mRNA expression for the epsilon2 subunit across the lifespan appeared to be related to the changes in NMDA receptor binding in the lateral cortex, even though the protein expression of the epsilon2 subunit did not show the same pattern of expression as the mRNA during development. The changes in epsilon2 subunit mRNA expression during adult aging may be a continuation of developmental processes, but there was also evidence that expression levels plateaued during early adulthood. The developmental expression of the zeta1subunit in the prefrontal/frontal cortex was influenced by gender and there was no significant effect of adult aging on either the protein or mRNA expression of this subunit. Determining how the expression of the NMDA receptor and its subunits change throughout the lifespan can help us to better understand the processes affecting the receptor during aging. These results should be useful for designing interventions into the aging process to repair or prevent changes in the NMDA receptor and its associated functions, such as learning and memory.

Aging↗

PubMed2002

Use of the Beck Scale for suicide ideation with psychiatric inpatients diagnosed with schizophrenia, schizoaffective, or bipolar disorders.

To ascertain how useful the Beck Scale for Suicide Ideation (BSI; Beck & Steer, Manual for Beck Scale for Suicide Ideation (1991)) would be for assessing the severity of suicidal ideation in patients who were diagnosed with schizophrenia, schizoaffective, or bipolar disorders, 142 inpatients were asked to complete the BSI. Eight (6%) patients refused, and four patients (3%) were unable to complete the BSI because they were unable to concentrate. Of the 130 patients who completed the BSI, 53 (41%) had schizoaffective, 37 (28%) had paranoid schizophrenia, 30 (23%) had manic bipolar, and 10 (8%) had depressed bipolar disorders. The coefficient alpha for the BSI was .96, and its one-week test-retest reliability for a subsample of 15 inpatients was 0.88, p < 0.001. The BSI total scores were positively correlated with having ever attempted suicide, r = 0.46, p < 0.001. According to the BSI, 36 (28%) patients were classified as current suicide ideators. The results were discussed as supporting the use of the BSI with inpatients who are diagnosed with schizophrenia, schizoaffective, or bipolar disorders.

Adolescent↗

PubMed2002

T2 relaxation time histograms in multiple sclerosis.

An accurate measurement of the transverse relaxation time T(2), and the histogram of T(2) in the brain parenchyma can be accomplished in vivo using a multi-echo magnetic resonance imaging sequence. An estimate of the error in the T(2) measurement is derived using copper sulfate doped water phantoms. Correction factors are calculated and applied to the signal intensity of each voxel prior to the in vivo T(2) evaluation. These corrected T(2) are in good agreement with the theoretical values calculated from copper sulfate concentrations. This technique is then applied to calculate T(2) histograms of the brain. The population studied was composed of normal volunteers and multiple sclerosis patients. The corrected T(2) histogram method discriminates the normal control population from the MS population, and also discriminates between relapsing-remitting patients and primary progressive or secondary progressive patients. Moreover using this approach we are able to detect in MS patients a global shift of the T(2) of the white mater toward higher values. The results of this study showed that the method is easy to implement and may be used to characterize MS pathology.

Brain↗

PubMed2001

Acute ethanol intoxication suppresses lung chemokine production following infection with Streptococcus pneumoniae.

Alcohol intoxication impairs neutrophil function and increases host susceptibility to Streptococcus pneumoniae. In a rat model of pneumonia, the effects of acute intoxication were monitored for lung chemokine responses, neutrophil recruitment, and bactericidal activity. Alcohol delayed lung neutrophil recruitment, increased bacterial burden, and decreased survival. Before neutrophil recruitment, bronchoalveolar lavage (BAL) macrophage inflammatory protein-2 (MIP-2) and cytokine-induced neutrophil chemoattractant (CINC) were decreased by alcohol. This alcohol-induced effect was reversed at 6 h, when there were large numbers of neutrophils in control BAL fluid, compared with the alcohol-treated group. Cyclophosphamide-induced neutropenia decreased neutrophil recruitment, minimizing the effects of recruited neutrophils on chemokine levels, and extended the alcohol-induced chemokine suppression. MIP-2 and CINC mRNA contents also were suppressed by alcohol 4 and 6 h after infection. Thus, alcohol suppresses lung chemokine activity in response to S. pneumoniae, which is associated with delayed neutrophil delivery, elevated bacterial burden, and increased mortality.

Alcoholic Intoxication↗

PubMed2001

Requirement of interleukin 17 receptor signaling for lung CXC chemokine and granulocyte colony-stimulating factor expression, neutrophil recruitment, and host defense.

Bacterial pneumonia is an increasing complication of HIV infection and inversely correlates with the CD4(+) lymphocyte count. Interleukin (IL)-17 is a cytokine produced principally by CD4(+) T cells, which induces granulopoiesis via granulocyte colony-stimulating factor (G-CSF) production and induces CXC chemokines. We hypothesized that IL-17 receptor (IL-17R) signaling is critical for G-CSF and CXC chemokine production and lung host defenses. To test this, we used a model of Klebsiella pneumoniae lung infection in mice genetically deficient in IL-17R or in mice overexpressing a soluble IL-17R. IL-17R-deficient mice were exquisitely sensitive to intranasal K. pneumoniae with 100% mortality after 48 h compared with only 40% mortality in controls. IL-17R knockout (KO) mice displayed a significant delay in neutrophil recruitment into the alveolar space, and had greater dissemination of K. pneumoniae compared with control mice. This defect was associated with a significant reduction in steady-state levels of G-CSF and macrophage inflammatory protein (MIP)-2 mRNA and protein in the lung in response to the K. pneumoniae challenge in IL-17R KO mice. Thus, IL-17R signaling is critical for optimal production of G-CSF and MIP-2 and local control of pulmonary K. pneumoniae infection. These data support impaired IL-17R signaling as a potential mechanism by which deficiency of CD4 lymphocytes predisposes to bacterial pneumonia.

Animals↗

PubMed2001

Utility of semiquantitative polymerase chain reaction for Epstein-Barr virus to measure virus load in pediatric organ transplant recipients with and without posttransplant lymphoproliferative disease.

We examined the utility of Epstein-Barr virus (EBV) load as a test for the presence of posttransplant lymphoproliferative disease (PTLD). A semiquantitative (SQ) EBV polymerase chain reaction (PCR) on peripheral blood mononuclear cells (PBMC) was used to determine virus load. We compared the values from pediatric patients, both with and without PTLD, with those from healthy pediatric and adult subjects. The virus loads for asymptomatic healthy subjects had a range of 0-1 log10 cells/10(6) PBMCs. Among transplant recipients (n=135), the mean virus load (+/- standard deviation) at the time of diagnosis of PTLD was 3.1+/-1.2 log(10) cells/10(6) PBMCs versus a baseline value of 1.3+/-1.4 log(10) cells/10(6) PBMCs in children without PTLD (P<.0001). A cutoff of > or =3 log10 cells/10(6) peripheral blood leukocytes resulted in the following values for use of virus load as a test for PTLD: sensitivity, 69%; specificity, 76%; positive predictive value, 28%; and negative predictive value, 95%. We conclude that determination of EBV load by use of SQ PCR is more useful in ruling out than in indicating the presence of PTLD.

Adult↗

PubMed2001

Acute childhood encephalitis and Mycoplasma pneumoniae.

In a prospective 5-year study of children with acute encephalitis, evidence of Mycoplasma pneumoniae infection was demonstrated in 50 (31%) of 159 children. In 11 (6.9%) of these patients, M. pneumoniae was determined to be the probable cause of encephalitis on the basis of its detection in cerebrospinal fluid (CSF) by polymerase chain reaction (PCR) or by positive results of serologic tests for M. pneumoniae and detection of the organism in the throat by PCR. CSF PCR positivity correlated with a shorter prodromal illness (P=.015) and lack of respiratory symptoms (P=.06). Long-term neurologic sequelae occurred in 64% of probable cases. Thirty children (18.9%) who were seropositive for M. pneumoniae but did not have the organism detected by culture or PCR had convincing evidence implicating other organisms as the cause of encephalitis, suggesting that current serologic assays for M. pneumoniae are not sufficiently specific to establish a diagnosis of M. pneumoniae encephalitis.

Acute Disease↗

PubMed2001

The effects of granulocyte colony-stimulating factor and neutrophil recruitment on the pulmonary chemokine response to intratracheal endotoxin.

Although G-CSF has been shown to increase neutrophil (polymorphonuclear leukocyte, PMN) recruitment into the lung during pulmonary infection, relatively little is known about the local chemokine profiles associated with this enhanced PMN delivery. We investigated the effects of G-CSF and PMN recruitment on the pulmonary chemokine response to intratracheal LPS. Rats pretreated twice daily for 2 days with an s.c. injection of G-CSF (50 microg/kg) were sacrificed at either 90 min or 4 h after intratracheal LPS (100 microg) challenge. Pulmonary recruitment of PMNs was not observed at 90 min post LPS challenge. Macrophage inflammatory protein-2 (MIP-2) and cytokine-induced neutrophil chemoattractant (CINC) concentrations in bronchoalveolar lavage (BAL) fluid were similar in animals pretreated with or without G-CSF at this time. G-CSF pretreatment enhanced pulmonary recruitment of PMNs (5-fold) and greatly reduced MIP-2 and CINC levels in BAL fluid at 4 h after LPS challenge. In vitro, the presence of MIP-2 and CINC after LPS stimulation of alveolar macrophages was decreased by coculturing with circulating PMNs but not G-CSF. G-CSF had no direct effect on LPS-induced MIP-2 and CINC mRNA expression by alveolar macrophages. Pulmonary recruited PMNs showed a significant increase in cell-associated MIP-2 and CINC. Cell-associated MIP-2 and CINC of circulating PMNs were markedly increased after exposure of these cells to the BAL fluid of LPS-challenged lungs. These data suggest that recruited PMNs are important cells in modulating the local chemokine response. G-CSF augments PMN recruitment and, thereby, lowers local chemokine levels, which may be one mechanism resulting in the subsidence of the host proinflammatory response.

Animals↗

PubMed2001

Snoring and sleep disturbance among children from an orthodontic setting.

Studies of snoring and sleep disturbance in the United States have been predominantly in clinic-based settings of children suspected to have obstructive sleep apnea hypopnea syndrome. Therefore, the purposes of this study were to utilize an orthodontic setting in which healthy children were seen regularly to study the prevalence of snoring and sleep disturbance among 405 children aged 6 to 17 years of age and to identify specific sleep behavior patterns associated with the increased odds of snoring. A sleep behavior questionnaire was administered to the child's parent or guardian. The questionnaire responses were analyzed using chi(2) analysis, and factor analysis was used to extract meaningful domains. The selected domains were used later in a logistic model to calculate the odds of snoring. The results indicated that 17% of the children habitually snored. The odds of snoring were approximately three times greater among mouth breathers and children who slept with their head tipped back and 1.5 times greater among those with morning headaches and frequent coughs and colds. In conclusion, snorers have significantly more sleep behavior problems than do non-snorers.

Adolescent↗

PubMed2001

Subgrouping persons with snoring and/or apnea by using anthropometric and cephalometric measures.

Craniofacial and anthropometric characteristics are identified risk factors for obstructive sleep apnea syndrome (OSAS). Phase 1 of this study used cephalometric radiographs to record craniofacial measurements from 60 OSAS subjects with a respiratory disturbances index (RDI) of 20 or greater (group A) and 60 subjects with a history of loud snoring and an RDI less than 20 (group B). From this data set, a craniofacial risk index (CRI) was constructed using age, body mass index (BMI), and 14 cephalometric measures previously reported to be associated with OSAS. A separating boundary (CRIS) was established by using discriminant analysis to differentiate between the two groups. All measurements were determined by an investigator who was blinded to the subjects' RDI score. Phase 2 used a second sample of 19 group A and 47 group B subjects to test the ability of the CRI derived from the first sample to classify subjects in this second sample into the correct age group. The CRI was able to classify correctly 72.3% (34 of 47) of the group A subjects when all variables were used in the discriminant model. Using only four variables (age, BMI, hyoid mandibular plane distance, and tongue length) selected by the stepwise method, 72.3% (34 of 47) of the group B subjects and 78.7% of group A subjects were classified correctly. These results suggest that a stepwise CRI could be used to classify heterogeneous groups of individuals with increased RDI into subgroups with varying degrees of anatomic risk for disease. Such subgrouping by anatomic risk could be important in determining the pathophysiology of OSAS because it is likely that differences in upper airway anatomy among individuals interacts with a variety of other factors to produce clinical illness.

Adult↗

PubMed2001

Highlights of a ten-year experience with the Ross procedure.

BACKGROUND: A review of a 10-year experience with the Ross procedure as a root replacement by a single group of surgeons featuring specific highlights is presented. Highlights include our results from a subset of patients with endocarditis and their management and a comparison of outcomes in patients with aortic insufficiency based on technical changes made after 5 years' experience. METHODS: The total patient group was 191, with 148 male and 43 female participants with an age range from 1 day to 69 years. Five of the patients in the 0-to-20 age group were newborns. Fifty-three of the adults were operated on for infectious endocarditis. In the total patient group 43% had aortic insufficiency, 28% had aortic stenosis, and 29% had mixed disease. RESULTS: Operative mortality was 5.2% with a late mortality of 2.6%. The actuarial survival was 90.2% at 10 years. Freedom from autograft explantation was 93.2% and freedom from homograft replacement was 98.4%. The endocarditis patients had an operative mortality of 3.8% with 100% cure of the infection. Freedom from reinfection on the autograft was 98.1%, and freedom from infection of the pulmonary homograft was 98.1%. The actuarial survival was 86.3%. CONCLUSIONS: A specific review of the patients with aortic insufficiency resulted in a failure of the autograft in 7 patients among a cohort of 41 during the first 5 years of the study. After a change in technique in which the aortic annulus is narrowed and fixed to a measured size to match the body surface area, we have had no failures in the autograft. Although these results are early, we believe that these data support the use of the autograft as an excellent choice for replacement of the aortic valve in infective endocarditis. Finally, the use of the autograft for aortic insufficiency is reasonable with fixation of the aortic annulus so that subsequent dilation does not occur.

Adolescent↗

PubMed2001

Flue gas desulfurization by-products additions to acid soil: alfalfa productivity and environmental quality.

Flue gas desulfurization (FGD) by-products are created when coal is burned and SO2 is removed from the flue gases. These FGD by-products are often alkaline and contain many plant nutrients. Land application of FGD by-products is encouraged but little information is available related to plant responses and environmental impacts concerning such use. Agricultural lime (ag-lime) and several new types of FGD by-products which contain either vermiculite or perlite were applied at 0, 0.5, 1.0, and 2.0 times the soil's lime requirement (LR) rate to an acidic soil (Wooster silt loam). The highest FGD by-products application rate was equivalent to 75.2 Mg ha(-1). Growth of alfalfa (Medicago sativa L.) was significantly increased compared to the untreated control in the second year after treatment with yields for the 1 x LR rate of FGD approximately 7-8 times greater compared to the untreated control and 30% greater than for the commercial ag-lime. Concentrations of Mo in alfalfa were significantly increased by FGD by-products application, compared to the untreated control, while compared to the ag-lime treatment, concentrations of B increased and Ba decreased. No soil contamination problems were observed, even at the 2xLR rate, indicating these materials can be safely applied to agricultural soils.

Agriculture↗