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Biomedical subjects

S Lewis

Publications and source records attributed to S Lewis.

At least 145 records · Page 8Linked to original sources

The union, the mining company, and the environment: steelworkers build a multi-stakeholder model for corporate accountability at Phelps Dodge.

This is a case study of ongoing relations between the Phelps Dodge mining company, a United Steelworkers local representing 560 employees at the company's Chino Mines in New Mexico, and an array of other concerned stakeholders. This case study shows that labor can be a full partner in environmental advocacy, and even take a leadership role in building a strong multi-stakeholder alliance for corporate accountability. While the case also shows that corporate jobs blackmail is alive and well in the global economy, the labor community-coalition that has emerged at the mining complex has broken some new ground. The approach taken attends to diverse stakeholder interests--cultural protection issues of Native-American and Mexican-American ethnic groups; conservation, groundwater and Right-to-Know issues of traditional environmental constituencies; and environmental liability and disclosure concerns of corporate shareholders. Among the key developments are: A new approach to corporate reporting to shareholders as an enforcement and right-to-know tool; The use of the internet as an information dissemination and action tool; The potential for environmentally needed improvements to serve as a receptor for employment of workers at a mine during periods of reduced production.

Journal Article↗

Treatment sequencing for implant restoration of partially edentulous patients.

Over the years implant companies have provided more and more components to address the varied clinical situations that occur. While these new components have allowed for improved restorative designs, it can now be somewhat confusing to determine the most appropriate components, especially abutments. This article describes restorative steps for both single-implant and multiple-implant restorations; these steps help guide restorative dentists through the treatment process, enabling them to follow standard protocols for single- and multiple-implant restorations. With these protocols it is possible to select the most appropriate components and proceed with treatment in a time-efficient and cost-effective manner.

Clinical Protocols↗

Cat allergen levels in public places in New Zealand.

AIMS: Cat allergen (Fel d 1) is a known risk factor for asthma. Studies have demonstrated Fel d 1 in both public buildings and domestic dwellings where cats have never been. The aims of this study were to measure reservoir Fel d 1 levels in public buildings in New Zealand, to examine determinants of these levels and to compare them with previously measured domestic levels. METHODS: Dust was obtained in two centres (Wellington and Christchurch) from hotels, hospitals, rest homes, churches, primary schools, childcare centres, cinemas, bank head offices and aeroplanes; and from North Island ski lodges. Measurements of temperature and relative humidity were taken. Information was collected on building characteristics. Fel d 1 levels (microg/g of fine dust) for floors (n=203), beds (n=64) and seats (n=24) were expressed as geometric means (95% confidence intervals). RESULTS: Detectable Fel d 1 levels were found in 95% of floor samples, 91% of bed samples and 100% of seat samples. Fel d 1 levels [geometric mean (95% confidence intervals)] were significantly higher on cinema and domestic aircraft seats [36.8 (20.8-65.3) microg/g and 33.3 (28.0-39.7) microg/g respectively] than on floors [3.6 (2.5-5.1) microg/g and 2.4 (1.8-3.0) microg/g respectively]. Floor Fel d 1 levels in the public buildings sampled were lower than those of domestic dwellings without cats [0.9 (0.6-1.4) microg/g vs 1.7 (1.2-2.4)] microg/g in Wellington and [2.0 (1.6-2.6) microg/g vs 4.0 (2.7-6.0] microg/g in Christchurch. After controlling for potential confounders, floor Fel d 1 levels were higher with carpeted floors (p<0.001) and lower in banks and hospitals (p<0.001). CONCLUSION: Fel d 1 levels in public buildings are low in New Zealand public places except for cinema and domestic aircraft seats where all but one sample had Fel d 1 levels potentially high enough to precipitate asthma symptoms in sensitised individuals.

Air Pollution, Indoor↗

A high throughput screen to identify secreted and transmembrane proteins involved in Drosophila embryogenesis.

Secreted and transmembrane proteins play an essential role in intercellular communication during the development of multicellular organisms. Because only a small number of these genes have been characterized, we developed a screen for genes encoding extracellular proteins that are differentially expressed during Drosophila embryogenesis. Our approach utilizes a new method for screening large numbers of cDNAs by whole-embryo in situ hybridization. The cDNA library for the screen was prepared from rough endoplasmic reticulum-bound mRNA and is therefore enriched in clones encoding membrane and secreted proteins. To increase the prevalence of rare cDNAs in the library, the library was normalized using a method based on cDNA hybridization to genomic DNA-coated beads. In total, 2,518 individual cDNAs from the normalized library were screened by in situ hybridization, and 917 of these cDNAs represent genes differentially expressed during embryonic development. Sequence analysis of 1,001 cDNAs indicated that 811 represent genes not previously described in Drosophila. Expression pattern photographs and partial DNA sequences have been assembled in a database publicly available at the Berkeley Drosophila Genome Project website (). The identification of a large number of genes encoding proteins involved in cell-cell contact and signaling will advance our knowledge of the mechanisms by which multicellular organisms and their specialized organs develop.

Animals↗

Atopic eczema and domestic water hardness.

BACKGROUND: The environment plays an important part in the aetiology of atopic eczema, but specific causes are unknown. Exposure to hard water is thought to be a risk factor for eczema. We undertook an ecological study of the relation between domestic water hardness and the prevalence of eczema among Nottinghamshire schoolchildren. METHODS: Questionnaire details of 1-year period and lifetime prevalence of eczema were obtained from parents of 4141 randomly selected primary-school children and 3499 secondary-school children in southern Nottinghamshire. Geographical information systems (GIS) were used to link the geographical distribution of eczema prevalence with domestic water-hardness data (four categories). Adjustment was made for potential confounding by sex, age, socioeconomic status, and access to health care. FINDINGS: Among the primary-school children there was a significant direct relation between both 1-year period and lifetime prevalence of eczema and water hardness, both before and after adjustment for confounders. The 1-year period prevalence was 17.3% (261/1509) in the highest water-hardness category and 12.0% (94/786) in the lowest (adjusted odds ratio 1.54 [95% CI 1.19-1.99] p for trend <0.001). The corresponding values for lifetime prevalence were 25.4% (384/1509) and 21.2% (167/786; adjusted odds ratio 1.28 [1.04-1.58], p for trend=0.02). Eczema prevalence trends in the secondary-school population were not significant (adjusted odds ratio for highest compared with lowest hardness category for 1-year prevalence 1.03 [0.79-1.33], p for trend=0.46; for lifetime prevalence 0.99 [0.83-1.23], p for trend=0.93). Eczema prevalence in primary-school children increased in relation to chlorine content of water, but the trend across four chlorine-content categories was not independently significant after adjustment for confounders. INTERPRETATION: Exposure to hard water in the home may increase the risk of eczema in children of primary-school age.

Adolescent↗

An informant interview for the diagnosis of dementia and depression in older adults (IDD-GMS).

BACKGROUND: There has been no instrument developed for the differential diagnosis of psychiatric conditions using an informant. The present study describes the development and validation of an informant interview for the diagnosis of dementia and depression in older adults (IDD-GMS). The IDD-GMs, as its name indicates, is based upon the well-established Geriatric Mental State Schedule (GMS). METHOD: Thirty older adults with psychiatric illnesses were identified. An informant/career was interviewed using the IDD-GMS. Questions from the GMS were altered to reflect the informant nature of interview. Validity was compared to ICD-10 diagnoses. Interrater reliability was determined. RESULTS: Using a hierarchical diagnostic system, receiver operating characteristics demonstrated one optimal cutpoint for sensitivity, > 13 for dementia and > 16 for depression, and one for specificity, > 13 for dementia and > 10 for depression. CONCLUSION: The validity and reliability of the IDD-GMS falls within acceptable limits and indicates that the IDD-GMS can be used as a diagnostic instrument for dementia and depression. The IDD-GMS represents the first informant interview to achieve this.

Adult↗

Hippocampal volumes in cognitively normal persons at genetic risk for Alzheimer's disease.

Brain imaging techniques have the potential to characterize neurobiological changes that precede the onset of cognitive impairment in persons at risk for Alzheimer's disease. As previously described, positron emission tomography (PET) was used to compare 11 cognitively normal persons 50 to 62 years of age who were homozygous for the epsilon4 allele of apolipoprotein E and 22 persons without the epsilon4 allele with a reported family history of Alzheimer's dementia who were matched for sex, age, and level of education. The epsilon4 homozygotes had significantly reduced glucose metabolism in the same brain regions as patients with Alzheimer's dementia; the largest reduction was in the posterior cingulate cortex. As described here, magnetic resonance imaging (MRI) was used to compare hippocampal volumes in the same subject groups. The epsilon4 homozygotes showed nonsignificant trends for smaller left and right hippocampal volumes; overall, smaller hippocampal volumes were associated with reduced performance on a long-term memory test. Whereas PET measurements of cerebral glucose metabolism begin to decrease before the onset of memory decline, MRI measurements of hippocampal volume begin to decrease in conjunction with memory decline in cognitively normal persons at risk for Alzheimer's disease.

Aged↗

Purification and biochemical properties of soluble recombinant human Bax.

Bax is a member of the Bcl-2 protein family with proapoptotic properties. The proteins of this family contain three highly conserved regions termed BH1, BH2, and BH3 as well as a hydrophobic COOH-terminal domain, which is responsible for the membrane attachment of the proteins. We have expressed human Bax truncated of the 20 amino acid COOH-terminal hydrophobic domain to obtain large amounts of soluble protein suitable for biochemical and structural studies. The truncated protein was expressed as a glutathione S-transferase (GST) fusion protein in Escherichia coli. The GST-Bax fusion protein was bound to glutathione-Sepharose, and Bax was released by thrombin cleavage and further purified by sequential chromatography on heparin-Sepharose and DEAE-Sepharose. The purified protein was present in solution as a heptamer and multimers of the heptamer complex. Limited tryptic digestion cleaved the protein in the region preceding the BH3 domain and produced a specific stable protein fragment of 15 kDa. Phosphorylation has been proposed as a possible regulatory mechanism of the bcl-2 proteins. The Bax protein was an in vitro substrate for specific serine/threonine protein kinases.

Amino Acid Sequence↗

Determining cerebral perfusion pressure thresholds in severe head trauma.

Laboratory studies suggest the pulsatile component of the transcranial doppler (TCD) waveform may be useful in determining lower autoregulatory threshold. This study aimed to assess the effect of increasing CPP on jugular bulb oximetry (SjO2) and middle cerebral artery (MCA) TCD flow velocities in the early management of severe head injury. 16 severely head injured patients (GCS < or = 8), had intracranial pressure (ICP), mean arterial pressure, SjO2 and MCA Doppler velocity monitored continuously. CPP was increased by intravenous fluids (right atrial pressure approximately equal to 10) and supplemented with adrenaline infusion until TCD pulsatility (Gosling pulsatility index [PI] reached a plateau. The mean CPP at which SjO2 surpassed 55% was 62 +/- 6.2 mm Hg. TCD PI did not plateau until a significantly higher mean CPP of 74 +/- 5.1 mm Hg was achieved (p < 0.01). In 8 cases, increased CPP was associated with a fall in ICP, ranging from 1 to 8 mm Hg. We conclude that a critically low level of SjO2 is a late indicator of failed autoregulation. CPP values associated with intact autoregulation identified by TCD assessment of MCA flow are significantly higher than those indicated by SjO2 monitoring. MCA Doppler flow assessment may be useful in determining the level of CPP at which therapy should be aimed in the early resuscitation of head trauma.

Adolescent↗

Diffuse neuronal perikaryon amyloid precursor protein immunoreactivity in a focal head impact model.

Amyloid precursor protein (APP) has been shown to accumulate in traumatically injured axons as early as 1 hour after injury. This accumulation may be due to interruption of fast axoplasmic transport and/or upregulation of APP synthesis. The aim of this study was to examine the neuronal cell body response to head impact using APP immunostaining in a focal non-missile head impact model. Ten anaesthetised and ventilated 2 year old Merino ewes were subjected to graded impact in the left temporal region by captive bolt. 2 hours after impact the brain was perfused fixed with formaldehyde. The tissue was mounted in paraffin, sectioned and stained with a monoclonal antibody to APP and standard H&E stain. APP positivity was semi-quantitated using a modification of our previously described sector scoring system [1]. Widespread neuronal APP positivity was found in the cerebral hemispheres and brain stem distant from the site of focal injury in all 10 animals. The most prominent APP positivity was found in the nerve cell bodies of the impacted left cerebral hemisphere. APP positive neurons were also found within regions which were structurally normal when stained with H&E. These results demonstrate diffuse neuronal perikaryon APP immunoreactivity following a focal head impact injury. The expression of APP within the neuronal cell body may be due to upregulation of APP synthesis or alterations in the availability of epitopes of APP. Further studies are in progress to address these hypotheses.

Amyloid beta-Protein Precursor↗

Biologic pollution in infant bedding in New Zealand: high allergen exposure during a vulnerable period.

BACKGROUND: High exposure to house dust mite and cat allergens in early life predisposes to allergic sensitization and to the development and persistence of asthma. Prevalence and severity of asthma are high in New Zealand. OBJECTIVE: The objective of this study was to determine the concentrations of Der p 1 and Fel d 1 in infant bedding in Wellington, New Zealand. METHODS: Infants were visited at home at a mean age of 11 weeks and again at 15 months. The concentration (microgram/g fine dust) and content (microgram/m2) of Der p 1 (154 infants) and Fel d 1 (75 infants) were measured in dust samples taken from each infant's bed. RESULTS: At 11 weeks, geometric mean (95% confidence intervals) Der p 1 levels were 18.3 micrograms/g (13.8 to 24.1) and 3.51 micrograms/m2 (2.4 to 5.2). By 15 months, Der p 1 had risen significantly to 44.0 micrograms/g (35.0 to 55. 3) and 49.0 micrograms/m2 (36.0 to 66.8). Bedding that included a sheepskin was used by a third of the infants and contained higher concentrations (microgram/g) and content (microgram/m2) of Der p 1 than beds without sheepskins. Cat ownership was the major determinant of Fel d 1 levels, with 48% of infants living with cats. At the first visit, the mean concentration of Fel d 1 in bedding was 44.6 micrograms/g (23.5 to 84.9) for houses with cats and 3.0 micrograms/g (2.1 to 4.3) for those without cats, remaining essentially unchanged at the second visit. When expressed as micrograms per square meter, there was a significant increase between visits, from 8.1 (3.9 to 16. 6) to 39.6 (19.9 to 78.5) in the cat-inclusive households. CONCLUSIONS: Extremely high levels of house dust mite allergen have been found in these infants' environments, which, together with the high levels of cat allergen in almost half who kept cats, are likely to be a major determinant of asthma prevalence and severity in New Zealand.

Allergens↗