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Biomedical subjects

C Hawes

Publications and source records attributed to C Hawes.

15 recordsLinked to original sources
PubMed1995

Phospholipid coatings for the prevention of membrane fouling.

The aim of the present work was the development of phosphorylcholine-based treatments for biofiltration membranes and the demonstration that such treatments prevent or inhibit protein fouling. Microfiltration membranes of cellulose triacetate, polyether sulphone and polyvinylidene fluoride were etched with oxygen in a plasma chamber to generate surface hydroxyl groups and were then treated with the monomer 2-methacryloyloxyethyl phosphorylcholine. These membranes were evaluated with water, buffer, bovine serum albumin (BSA), yeast fermentation broth, beer and orange juice. The treatment of cellulose triacetate membranes reduced both the initial flux and the extent of water fouling. In terms of the integrated flux, these factors tended to cancel each other out. For protein, the membranes gave similar or higher fluxes but worse fouling. The cellular feed (yeast) reacted more favourably to the coating than the BSA. The polyether sulphone was scarcely affected by the coating; fouling remaining high with most 'real' feeds. There was lower initial flux but less flux decline with water and beer. Washing with water and cleaning with Tergazyme did not restore the initial flux. Polyvinylidene fluoride membranes gave the most positive results. In most cases, the coating both increased initial flux and decreased the rate of fouling. The coating was particularly effective for BSA and for beer and orange juice, where fouling is probably caused by a polysaccharide rather than by a protein. Electron microscopy showed, nonetheless, that fouling by proteins was accompanied by protein adsorption primarily on the upper surface of the membrane and that coated membranes showed less deposition and in different places than did untreated membranes.

Antifoaming Agents↗
PubMed1995

The structure of social engagement among nursing home residents.

This research tests the reliability and construct validity of social engagement, a new quality of life measure embedded in the federally mandated Resident Assessment Instrument (RAI) for the nursing home population. The sample consisted of 1,848 residents from 268 homes in 10 states with data collected by trained research nurses. Three resident groups were formed based on residents' cognitive and ADL functioning. Social engagement was significantly related to average time spent in activities across all three groups. We hypothesized a four-factor model with social engagement distinct from mood problems, conflicted relationships, and behavior problems. LISREL confirmatory factor analysis found the data to be consistent with this hypothesis (Fit Index > .98). Intercorrelations between factors showed that for high-functioning residents, engagement was negatively related to conflict but was positively related to conflict among the most impaired. The validity of the social engagement measure and its stability across types of residents suggest its potential utility as a marker of nursing home quality.

Activities of Daily Living↗
PubMed1995

Reliability estimates for the Minimum Data Set for nursing home resident assessment and care screening (MDS).

The MDS is a core set of items, definitions, and response categories used to assess all of the nation's 1.5 million nursing home residents who reside in facilities participating in the Medicare or Medicaid programs. Further, the Health Care Financing Administration (HCFA) has proposed a rule that would require facilities to computerize MDS data and submit it to state and federal agencies, paving the way for a national database. This article describes the process of testing the reliability of the MDS items in 13 nursing homes in five states. The results demonstrate that MDS data gathered in a research effort attain reliabilities that make such data useful. MDS items met a standard for excellent reliability (i.e., intraclass correlation of .7 or higher) in key areas of functional status, such as cognition, ADLs, continence, and diagnoses. Sixty-three percent of the items achieved reliability coefficients of .6 or higher. Eighty-nine percent of the items in the MDS achieved .4 or higher.

Activities of Daily Living↗
PubMed1995

Psychotropic use among older residents of board and care facilities.

OBJECTIVE: To describe patterns of psychotropic use as well as clinically relevant and concurrent nonpsychotropic use among older residents of board and care facilities in 10 states. METHODS: Weighted use rates were based on data from a sample of 2054 residents aged 65 and older from 410 facilities in 10 states, drawn via a complex, multistage sampling design. Data, including drug name, use frequency, and PRN use, were collected on all drugs taken by the resident during a 7-day period. During face-to-face interviews with residents and/or proxies, data were also collected on resident characteristics. SUBJECTS: The majority of subjects were female, white, and widowed. Average age was 82 years. Approximately 25% had a current mental or emotional condition, and 8% had been hospitalized for a psychiatric condition during the year before admission. More than half needed help with at least one activity of daily living. Forty percent had moderate or severe cognitive impairment, and 18% had received mental health care during the previous year. ANALYSES: Weighted descriptive analyses were performed with Software for Survey Data Analysis (SUDAAN), which accounts for the complex, multistage sampling design. RESULTS: Approximately 35% of the older residents used at least one psychoactive agent, with 30% of psychotropic users receiving two to four different psychotropic medications. Use rates decline with age, for psychotropics overall and for therapeutic classes. Results revealed potentially problematic polypharmacy in relation to drug duplication within therapeutic classes, use of multiple psychotropics across classes, and concurrent nonpsychotropic use. CONCLUSIONS: Compared with community-dwelling older adults, this study revealed high psychotropic use rates among older board and care facility residents. Overall, our results suggest that serious consideration be given to the apparent need for systematic drug utilization review, a potentially useful program that is mandated in other settings.

Aged↗
PubMed1994

MDS Cognitive Performance Scale.

BACKGROUND: Chronic cognitive impairment is a major problem in U.S. nursing homes, yet traditional assessment systems in most facilities included only limited information on cognitive status. Following the Congressional mandate in the Omnibus Reconciliation Act of 1987 (OBRA '87), U.S. nursing homes now complete the Minimum Data Set (MDS), a standardized, comprehensive assessment of each resident's functional, medical, psychosocial, and cognitive status. We designed a Cognitive Performance Scale (CPS) that uses MDS data to assign residents into easily understood cognitive performance categories. METHODS: Information was drawn from three data sets, including two multistate data sets constructed for the Health Care Financing Administration. The prevalence and reliability of the MDS cognitive performance variables were established when assessed by trained nursing personnel. Five selected MDS items were combined to create the single, functionally meaningful seven-category hierarchical Cognitive Performance Scale. RESULTS: The CPS scale corresponded closely with scores generated by the Mini-Mental State Examination and the Test for Severe Impairment, nursing judgments of disorientation, and neurological diagnoses of Alzheimer's disease and other dementias. CONCLUSIONS: The new CPS provides a functional view of cognitive performance, using readily available MDS data. It should prove useful to clinicians and investigators using the MDS to determine a resident's cognitive assets.

Activities of Daily Living↗
PubMed1994

Authentic processing and targeting of active maize auxin-binding protein in the baculovirus expression system.

The major auxin-binding protein (ABP1) from maize (Zea mays L.) has been expressed in insect cells using the baculovirus expression system. The recombinant protein can be readily detected in total insect cell lysates by Coomassie blue staining on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Our data suggest that ABP1 is processed similarly in both insect cells and maize. The signal peptide is cleaved at the same position as in maize and the mature protein undergoes tunicamycin-sensitive glycosylation, yielding a product with the same mobility on SDS-PAGE as authentic maize ABP1. On immunoblots the expressed protein is recognized by anti-KDEL monoclonal antibodies. Immunofluorescence localization demonstrates that it is targeted to and retained in the endoplasmic reticulum of insect cells in accordance with its signal peptide and KDEL retention sequence. The expressed ABP1 also appears to be active, since extracts of insect cells expressing ABP1 contain a saturable high-affinity 1-naphthylacetic acid-binding site, whereas no saturable auxin-binding activity is detected in extracts from control cells.

Amino Acid Sequence↗
PubMed1992

Nursing home case-mix classification and residents suffering from cognitive impairment: RUG-II and cognition in the Texas case-mix data base.

Case-mix reimbursement systems for nursing home care are now in use or under consideration in over 20 states. Though many in the long-term care field still debate the relative merits of the various systems, those systems based on the Resource Utilization Groups-II (RUG-II) system used in New York seem to be increasingly popular. However, one of the more serious questions raised concerning RUG-like systems is whether they fully acknowledge the role played by cognitive deficits in determining nursing home residents' care needs. The results of this research indicate: 1) that resource provision and cognitive status are correlated, 2) that residents with higher levels of cognitive impairment appear most frequently in RUG-II categories that have higher case-mix weights, 3) that simply adding some measure of cognitive function does not significantly increase the power of these models, and 4) that the RUG-II model predicts the level of care resources provided to the cognitively intact much better than it predicts those provided to residents suffering from relatively severe disorientation. These results imply that such classification systems may create disincentives for the admission of the most cognitively impaired residents and that the care of these individuals, more than others, may be dependent on facility-to-facility variation.

Activities of Daily Living↗
PubMed1992

Immunological evidence that plants use both HDEL and KDEL for targeting proteins to the endoplasmic reticulum.

The epitopes of two monoclonal antibodies raised to a putative auxin receptor have been mapped. Carboxy-peptidase A digestion of the antigen, auxin-binding protein (ABP) purified from maize, completely abolished binding of antibody MAC 256 and impaired binding of MAC 259, suggesting that they both recognise C-terminal epitopes. Published sequences of ABP showed that the C terminus was KDEL, a tetrapeptide used for targeting proteins to the ER in animal cells. We have used this short homology to confirm that the two monoclonals recognise C-terminal KDEL, showing that animal KDEL proteins and synthetic KDEL peptides are recognised and that animal cell ER is stained strongly and specifically. Sucrose density gradient fractionation of maize microsomal membranes showed that plant KDEL proteins, including ABP, fractionated with markers for the endoplasmic reticulum. However, few proteins are stained by anti-KDEL monoclonals in plants. For comparison, a monoclonal antibody raised to a synthetic HDEL peptide was also used and found to stain a set of proteins in all plant species tested. The anti-HDEL and anti-KDEL monoclonals were sequence specific, staining different proteins. On density gradient fractionation HDEL proteins also banded with ER marker activities. However, the intracellular distribution of HDEL and KDEL proteins determined by immunofluorescence was different. Whereas HDEL proteins showed a distribution characteristic of plant ER, and this localisation was confirmed by immunogold labelling of ultrathin sections and electron microscopy, KDEL proteins showed strong fluorescence in discrete parts of the cell cortex. These observations are discussed in terms of the potential these monoclonal antibodies have as markers for ER and of the role ABP plays in plant cell signalling.

Amino Acid Sequence↗
PubMed1990

Designing the national resident assessment instrument for nursing homes.

In response to the Omnibus Reconciliation Act of 1987 mandate for the development of a national resident assessment system for nursing facilities, a consortium of professionals developed the first major component of this system, the Minimum Data Set (MDS) for Resident Assessment and Care Screening. A two-state field trial tested the reliability of individual assessment items, the overall performance of the instrument, and the time involved in its application. The trial demonstrated reasonable reliability for 55% of the items and pinpointed redundancy of items and initial design of scales. On the basis of these analyses and clinical input, 40% of the original items were kept, 20% dropped, and 40% altered. The MDS provides a structure and language in which to understand long-term care, design care plans, evaluate quality, and describe the nursing facility population for planning and policy efforts.

Centers for Medicare and Medicaid Services, U.S.↗
PubMed1985

A case of partial deficiency of alpha 1-antichymotrypsin.

A 20-year-old woman, admitted to a neurological ward with a diagnosis of benign intracranial hypertension, was found on specific protein electroimmunoassay to have a consistently decreased concentration of alpha 1-antichymotrypsin in her plasma. Serum from her father showed the same result. Further investigation of her family demonstrated that this partial deficiency was transmitted in an autosomal dominant fashion and was not associated with any obvious specific clinical abnormalities.

Adult↗
PubMed1982

The three-dimensional structure of the Z disc in insect supercontracting muscles.

Two type of Z disc structure have been reported in insect supercontracting muscle fibres: (i) a perforated Z disc where Z material forms a reticulum and (ii) a fragmented Z disc composed of separate, discrete Z bodies. The use of thick (1 micron) sections in conjunction with high voltage electron microscopy can distinguish between these two types while conventional thin sections may lead to misinterpretation of structure. It is shown that in one insect, the crane-fly Tipula, the larval body-wall muscles, for which a fragmented Z disc has been proposed, do in fact have a perforated disc. In the wax moth Galleria, homologous muscle fibres have a similar type of Z disc, a finding which indicates the need for re-examination of other lepidopteran muscles claimed to have fragmented discs. A redefinition of supercontraction is proposed which includes reference to the perforated type of Z disc.

Animals↗