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Biomedical subjects

K McMahon

Publications and source records attributed to K McMahon.

At least 19 recordsLinked to original sources
PubMed2001

Association of a novel PDZ domain-containing peripheral Golgi protein with the Q-SNARE (Q-soluble N-ethylmaleimide-sensitive fusion protein (NSF) attachment protein receptor) protein syntaxin 6.

PDZ domains are involved in the scaffolding and assembly of multi-protein complexes at various subcellular sites. We describe here the isolation and characterization of a novel PDZ domain-containing protein that localizes to the Golgi apparatus. Using an in silico cloning approach, we have identified and isolated a cDNA encoding a ubiquitously expressed 59-kDa protein that we call FIG. It is composed of two coiled coil regions, a leucine zipper, and a single PDZ domain. Cytological studies using indirect immunofluorescence microscopy revealed that FIG is a peripheral protein that uses one of its coiled coil domains to localize to the Golgi apparatus. To ascertain the modalities of this Golgi localization, the same coiled coil region was tested for its ability to interact with a panel of coiled coil domain-containing integral membrane Golgi proteins. Using a series of GST fusion protein binding assays, co-immunofluorescence and co-immunoprecipitation experiments, we show that FIG specifically binds to the coiled coil domain-containing Q-SNARE (Q-soluble NSF attachment protein receptor) protein syntaxin 6 both in vitro and in vivo. The structural features of FIG and its interaction with a SNARE protein suggest that FIG may play a role in membrane vesicle trafficking. This is the first example of a PDZ domain-containing peripheral protein that localizes to the Golgi through a coiled coil-mediated interaction with a resident membrane protein. Our results broaden the scope of PDZ domain-mediated functions.

Adaptor Proteins, Signal Transducing↗
PubMed2000

Nutritional screening and assessment.

OBJECTIVES: To review the components of nutritional screening, screening measures and tools, and the nurses' role in nutritional assessment. DATA SOURCES: Research studies, review articles, and book chapters. CONCLUSIONS: Timely and appropriate nutritional interventions require the adoption of routine initial nutritional screening, referral for comprehensive nutritional assessments as needed, and continued re-screening. IMPLICATIONS FOR NURSING PRACTICE: Oncology nurses should be prepared to contribute to a comprehensive nutritional assessment in their role as patient advocate and expert clinician.

Humans↗
PubMed2000

A health visitor for older people in an accident and emergency department.

Published studies indicate that older people have special needs on discharge from accident and emergency (A&E) departments that are not always fully met. The literature reflects that although a significant proportion of older people have a decrease in functional independence and an increased need for services following discharge from A&E, social and functional assessment by A&E staff can be inadequate, as can the arrangement of follow-up community services. As part of a wider study into the organization of care for older people in A&E, a health visitor for older people was funded to work part-time in the A&E department of a large NHS Trust. The health visitor identified potential clients through reviewing the A&E documentation of patients aged 75 years or over discharged directly from A&E. Telephone calls or home visits were used to follow up those individuals deemed to be vulnerable by the health visitor. Interventions included health education, referral to other agencies and patient or family counselling. None of the clients followed up by the health visitor (n = 212) had been referred by A&E to a specialist in gerontology, which suggests that these clients would otherwise not have received the potential benefit of specialist intervention. The pilot study described here highlights a number of practical issues in relation to the health visitor post for older people in A&E, including the importance of dedicated office space and access to a telephone. Data collected during the study, plus the positive evaluation of the role by a small group of A&E staff confirm the claims made in other studies (e.g. Runciman et al, 1996) that health visitors for older people may be of value in meeting the post-discharge needs of these people.

Accidental Falls↗
PubMed2000

Application of polyphosphate metabolism to environmental and biotechnological problems.

The synthesis and degradation of polyphosphate (polyP) are influenced by the energy state of the cell and extracellular phosphate levels. The import of excess phosphate and its incorporation into polyP under phosphate- and energy-rich growth conditions allows organisms to survive when phosphate or energy are depleted. Under phosphate-starvation conditions, phosphate can be recovered from polyP by hydrolysis. When the organism is energy starved, energy can be recovered either by regenerating the high-energy phosphoanhydride bond donor (ATP in most cases) or by hydrolysis of polyP and subsequent secretion of orthophosphate to recharge the transmembrane proton gradient. Understanding how the energy state of the cell and environmental phosphate levels affect polyP metabolism is essential to improving such environmental processes as enhanced biological phosphorus removal, a treatment process that is widely used to remove excess phosphate from wastewater. Manipulation of the genes responsible for polyP metabolism can also be used to improve gene expression from phosphate-starvation promoters and to remove heavy metals from contaminated environments.

Biotechnology↗
PubMed1998

Integrating proactive nutritional assessment in clinical practices to prevent complications and cost.

Timely and appropriate nutritional interventions for patients with cancer and/or human immunodeficiency virus (HIV) infection require adoption of routine nutritional screening and comprehensive evaluations into clinical practice. Traditionally, the clinical skills necessary for comprehensive nutritional evaluation have not been a part of medical education. Likewise, the importance of nutritional screening and assessment has not been fully appreciated. In the context of current health care, these skills are increasingly important in maintaining or improving patient care and improving clinical and economic outcomes. It is imperative that nutritional screening be routinely implemented in all clinical settings (eg, office practices, clinics, preadmission units, homecare) to offset the impact of decreased rates of hospital admission. Hospitals have traditionally been the setting for dietetic screening and intervention and nutritional support services. Therapy for patients with cancer or HIV infection is increasingly being managed primarily or entirely in an outpatient setting. When nutritional risk or deficit is identified on screening, it is important to carry out sequential reassessment after intervention. This article reviews the principles of nutritional screening and comprehensive assessment. It includes a detailed overview of an instrument that can be used for either nutritional screening or assessment in patients with either malignancy or HIV infection.

HIV Infections↗
PubMed1997

Effects of ethanol on nonspatial working memory and attention in rats.

Investigation into the neural basis for ethanol-induced cognitive dysfunction requires the use of valid animal models. An operant signal detection procedure was developed to assess simultaneously the processes of sustained attention and working memory in rats, and to determine the effects of ethanol on these cognitive functions. Ethanol, at 0.75 g/kg ip, produced delay- and stimulus length-dependent decreases in choice accuracy, effects that are consistent with deficits in both working memory and sustained attention. Local infusion of ethanol directly into the medial septal area resulted in a selective loss of choice accuracy at the long delay. The impairment by intraseptal ethanol did not interact with stimulus length. Thus, the working memory impairment, but not the decrement in sustained attention, was mimicked by intraseptal ethanol. The current model provides a foundation for studying the neural basis of ethanol's cognitive effects.

Animals↗
PubMed1996

Neuronal mechanisms mediating drug-induced cognition enhancement: cognitive activity as a necessary intervening variable.

The conceptual foundations of a research aimed at the determination of potential neuronal, neuropharmacological, and behavioral/cognitive mechanisms mediating drug-induced cognition enhancement are discussed. The available evidence justifies a focus on attentional processes as a target for drug-induced cognition enhancement. Neuropharmacological mechanisms that may mediate drug-induced enhancement of attentional functions are proposed to interact necessarily with attention-associated neuronal activity. The elements of a transsynaptic approach to increase the excitability of basal forebrain cholinergic neurons and hence, attentional functions are discussed. Experimental tests of this hypothesis require the demonstration of interactions between cognition-induced increases in the activity of cortical cholinergic afferents and the effects of putative cognition enhancers. The available data illustrate that the effects of benzodiazepine receptor (BZR) agonists and inverse agonists on cortical acetylcholine (ACh) efflux interact with the state of activity in this system. The feasibility, potential heuristic power, and the experimental and conceptual problems of studies attempting to simultaneously assess drug effects on behavioral/cognitive abilities, ACh efflux, and neuronal activity have been revealed by an experiment intended to correlate performance in a task measuring sustained attention with medial prefrontal ACh efflux and medial prefrontal single-unit activity. The rational development of a psychopharmacology of cognition enhancers requires a union among behavioral/cognitive pharmacology, neuropharmacological and electrophysiological approaches.

Acetylcholine↗
PubMed1996

Utilizing volunteer research assistants in epidemiologic studies.

Utilizing volunteers in research-assistant roles can provide a new model for extending research dollars in epidemiologic studies of the elderly. This is increasingly important with a rapidly growing older population suffering from an increasing prevalence of disability, disease, and the related medical costs. During a two-year cross-sectional study of factors that predict health aging conducted by the Buck Center for Research in Aging in Marin County, California, 82 volunteers were recruited and trained to fill roles often held by paid research assistants. The key activities of telephone screening, interviewing, coding, and data entry were successfully completed by trained volunteers following standards and within a time frame comparable to similar studies. Volunteer research assistants contributed approximately 13,600 hours that resulted in a savings in personnel costs of over $100,000. Many of the people recruited and trained as volunteer research assistants were healthy older adults and retired workers. The project utilized their transferable skills and talents in an interesting and productive capacity.

Aged↗
PubMed1995

Ethanol suppresses the induction of long-term potentiation in vivo.

Long-term potentiation (LTP), a leading neural mechanism of memory, is profoundly affected by ethanol in vitro, but ethanol's effect on LTP in vivo has not been studied at doses known to impair memory. In this study, LTP was induced in the dentate hilus by theta-pattern stimulation of the perforant path. Dentate evoked responses were recorded during a 3 h session in which rats pressed a lever on a fixed interval (30 s) schedule of reinforcement. Following theta-pattern stimulation, rats pretreated with saline had significant LTP that was present throughout the session. LTP was measured as an increase in the initial slope and the population spike of the evoked response. The potentiation was no longer present 24 h after stimulation. Ethanol (0.5 g/kg and 1.0 g/kg) blocked LTP and attenuated short-term frequency potentiation in a dose-dependent fashion. Although ethanol produced a decrease in rewarded lever pressing, lever pressing was not correlated to any measure of the evoked response. Ethanol, when given 60 min after theta-pattern stimulation, did not alter the expression of LTP. The results demonstrate that low doses of ethanol selectively blocked the induction of LTP in vivo, an effect that may underlie ethanol's impairment of memory.

Animals↗
PubMed1995

Health and functioning among the elderly of Marin County, California: a glimpse of the future.

BACKGROUND: The purpose of this study was to obtain information concerning the health status of the theoretically advantaged elderly population of Marin County, California, and to compare these data with those from other populations with different levels of socioeconomic status. METHODS: An age-stratified sample of 2,018 community-dwelling elderly residents of Marin was selected, and these participants were interviewed between 1989 and 1991. Interview items included medical history of life-threatening diseases and chronic conditions, reported and observed disabilities, and life-style characteristics. RESULTS: While the residents of Marin had lower mortality rates than the total U.S. population, there were few meaningful differences in measures of health and function in comparison to other elderly populations with substantially lower levels of socioeconomic status. The main exceptions were better memory performance and lower depressive symptomatology in Marin. Because of the many methodological differences, these comparisons must be viewed with caution. CONCLUSION: The general pattern of findings in this study indicates that while death has been postponed in this socioeconomically advantaged population, the prevalence of disease and disability has not. If true, this implies that residents of an affluent community can spend a longer rather than shorter period of their late life in a state of infirmity and in need of medical care. This appears to be especially true for women.

Activities of Daily Living↗
PubMed1995

Finding a "healthy" medium.

Home health care is an integral part of the health care system. As home care grows--a natural outcome with a growing elderly population and earlier discharges from the hospital under DRGs--so do the many challenges. Proposed Medicare budget cuts, managed care and Medicaid block grants are just a few of the pressing issues faces by not only home care, but the entire health care industry.

Diagnosis-Related Groups↗
PubMed1995

Multiple organ failure: the final complication of critical illness.

The exact mechanisms responsible for the development and perpetuation of MOF are just beginning to be unraveled. Nurses must have an understanding of the progression of MOF and the physiologic and psychologic responses of the patient. Although caring for patients with MOF is not an easy task, the critical care nurse is in a pivotal role to make a difference in the outcome of these patients.

Critical Illness↗
PubMed1992

Evaluation of the use and usefulness of telephone consultations in one general practice.

In one practice with 14,000 patients an advice line was set aside at designated times to enable patients to speak directly to a doctor on the telephone. The aim of this study was to determine who used the line, why they called, the conditions callers presented with, the action taken by the doctor and whether patients and doctors thought the service was a good idea. A total of 277 calls were made during the five month study period. Responses to a questionnaire were received from doctors for all 277 calls and from 152 patients. It was found that most calls lasted about three minutes. Most of the callers (59%) were known to the doctor taking the call. Users of the advice line were most likely to be women, married people and people with children. Equal numbers of calls were received about new and existing problems. The most frequent reason for calling was to obtain the result of a test (21% of calls). The most frequent diagnosis by the doctors was chronic complaints for which the patient was already receiving treatment (19%). The data from patients and doctors were similar. In 30% of cases callers were advised to take medicine, mostly a prescription to be collected (16%), while a few callers received a home visit (7%). Doctors thought they provided reassurance in 26% of cases while callers thought they had received reassurance in 43% of cases. If the advice line had not been available three quarters of the respondents would have made an appointment and 13% would have asked the doctor to make a home visit.(ABSTRACT TRUNCATED AT 250 WORDS)

Attitude of Health Personnel↗
PubMed1988

The accuracy of selective magnetic resonance imaging compared with the findings of arthroscopy of the knee.

The results of selective magnetic resonance imaging of the knee were compared with those of arthroscopy in a prospective series of fifty patients. A specifically designed protocol for imaging, producing T1 sagittal images interleaved at four millimeters while the patient's foot was in 20 degrees of external rotation, was utilized. This technique, called selective magnetic resonance imaging, yielded excellent visualization of the posterior cruciate ligament, medial meniscus, and lateral meniscus in all patients. However, in only 76 per cent of the patients was the anterior cruciate ligament well visualized. Compared with arthroscopy, the sensitivity, specificity, and accuracy of selective magnetic resonance imaging were, respectively, 95.8, 100, and 98 per cent for tears of the medial meniscus; 66.7, 95.1, and 90 per cent for tears of the lateral meniscus; undefined, 100, and 100 per cent for tears of the posterior cruciate ligament; and 100, 96.9, and 97.3 per cent for tears of the anterior cruciate ligament, when that ligament was well visualized. Our selective sequence can be performed in fifteen minutes at a cost that is comparable with that of arthrography. It is totally non-invasive and requires no exposure to ionizing radiation. Selective magnetic resonance imaging can be a safe and valuable adjunct to the clinical evaluation of the knee and an aid to efficient preoperative planning.

Adolescent↗