PubMed Health⌕ Search

Biomedical subjects

R Shepherd

Publications and source records attributed to R Shepherd.

At least 37 records · Page 2Linked to original sources
PubMed1998

Interpretations of healthy and unhealthy eating, and implications for dietary change.

Central to many considerations of health-related dietary change is the interpretation given to 'healthy' and 'unhealthy' eating. Results are reported from two studies which investigated people's understanding of these concepts. The first study involved structured interviews with 48 respondents: a wide range of interpretations of healthy and unhealthy eating was found using content analysis techniques. The second study (n = 242) used questionnaires to assess the extent to which different interpretations were endorsed. The extent to which different eating behaviours were perceived as healthy or unhealthy varied greatly. A principal components analysis of perceptions of healthy and unhealthy eating produced five separate factors. Some differences in perceptions were found for people of different age, gender and educational level. Objectively assessed dietary intake and perceived intake were found to be two distinct quantities. 'Healthy' eaters were found to perceive 'healthy eating' slightly differently to 'unhealthy' eaters. The results suggest that lay understanding of healthy eating does generally conform with dietary guidelines, and therefore health promotion priorities should focus on physical and psychological constraints to healthy eating, rather than attempting to increase the public's knowledge as a whole.

Adolescent↗
PubMed1998

A urodynamic study of surface neuromodulation versus sham in detrusor instability and sensory urgency.

PURPOSE: We studied the effect of surface neuromodulation on cystometric pressure and volume parameters in women with detrusor instability or sensory urgency. Electrical current was delivered to the suprapubic region and third sacral foramina via a transcutaneous electrical nerve stimulator with sham neuromodulation control. MATERIALS AND METHODS: A consecutive series of women with proved detrusor instability or sensory urgency were randomized to 3 surface neuromodulation groups. Volume and pressure parameters were the main outcomes of transcutaneous electrical nerve stimulation applied during second cystometric fill. RESULTS: Sham transcutaneous electrical nerve stimulation did not alter the outcome measures. However, neuromodulation delivered across the suprapubic and sacral skin effected a reduction in mean maximum height of detrusor contraction. A current which inhibits motor activity was not superior to that which inhibits sensory perception in reducing detrusor pressure. Response in sensory urgency was poor. CONCLUSIONS: Results from our sham controlled study suggest that short-term surface neuromodulation via transcutaneous electrical nerve stimulation may have a role in the treatment of detrusor instability. Future studies must examine the clinical effect of long-term surface neuromodulation.

Adult↗
PubMed1998

Methodological approaches to assessing risk perceptions associated with food-related hazards.

The psychometric approach developed by Slovic and his co-workers has been effectively used to assess risk perceptions associated with different food-related hazards. However, further examination (using questionnaire data and partial correlation techniques) has indicated that technological hazards are highly differentiated from lifestyle hazards, in terms of both hazard control and knowledge about the hazard. Optimistic bias was also seen to vary between hazards. Further research has focused on a particular hazard, genetic engineering. Risk perceptions associated with genetic engineering are underpinned by ethical concern and questions relating to perceived need for the technology, as well as perceptions of risk or harm. However, increasing the specificity of hazard stimuli was found to alter the factor structure of underlying risk perceptions. The utility of preference mapping procedures in determining individual differences in trust in risk regulators is also discussed.

Bias↗
PubMed1997

Chitosan functional properties.

Chitosan is a partially deacetylated polymer of N-acetyl glucosamine. It is essentially a natural, water-soluble, derivative of cellulose with unique properties. Chitosan is usually prepared from chitin (2 acetamido-2-deoxy beta-1,4-D-glucan) and chitin has been found in a wide range of natural sources (crustaceans, fungi, insects, annelids, molluscs, coelenterata etc.) However chitosan is only manufactured from crustaceans (crab and crayfish) primarily because a large amount of the crustacean exoskeleton is available as a by product of food processing. Squid pens (a waste byproduct of New Zealand squid processing) are a novel, renewable source of chitin and chitosan. Squid pens are currently regarded as waste and so the raw material is relatively cheap. This study was intended to assess the functional properties of squid pen chitosan. Chitosan was extracted from squid pens and assessed for composition, rheology, flocculation, film formation and antimicrobial properties. Crustacean chitosans were also assessed for comparison. Squid chitosan was colourless, had a low ash content and had significantly improved thickening and suspending properties. The flocculation capacity of squid chitosan was low in comparison with the crustacean sourced chitosans. However it should be possible to increase the flocculation capacity of squid pen chitosan by decreasing the degree of acetylation. Films made with squid chitosan were more elastic than crustacean chitosan with improved functional properties. This high quality chitosan could prove particularly suitable for medical/analytical applications.

Animals↗
PubMed1997

The elaboration likelihood model and communication about food risks.

Factors such as hazard type and source credibility have been identified as important in the establishment of effective strategies for risk communication. The elaboration likelihood model was adapted to investigate the potential impact of hazard type, information source, and persuasive content of information on individual engagement in elaborative, or thoughtful, cognitions about risk messages. One hundred sixty respondents were allocated to one of eight experimental groups, and the effects of source credibility, persuasive content of information and hazard type were systematically varied. The impact of the different factors on beliefs about the information and elaborative processing examined. Low credibility was particularly important in reducing risk perceptions, although persuasive content and hazard type were also influential in determining whether elaborative processing occurred.

Adult↗
PubMed1996

Development of hearing and vocalization in a marsupial, the Northern Quoll, Dasyurus hallucatus.

The development of hearing was studied in the Northern Quoll, a nocturnal marsupial carnivore whose young are born into a pouch in an immature state after about 21 days in utero. Startle responses to noise bursts of 105 dB sound pressure level first appeared at 60 days after arrival in the pouch, but only to occasional stimuli; forelimb rather than whole body twitches were evoked. The latter were elicited regularly at 67 days onward. Auditory brainstem response (ABR) audiograms were measured during the period when startle responses first appeared. At 68 days responses were elicited between 1 and 16 kHz with thresholds in excess of 55 dB. At 81-88 days responses occurred over the adult range at lower thresholds than observed in the adult. The waveform of the ABR increased in complexity and decreased in latency during development. Pouch-young emitted acoustically well-defined isolation cells when separated from their mothers. Fourier analysis of these calls revealed peak energy at 8-11 kHz irrespective of the sex of the pouch-young. The isolation call first became evident at about 35 days, when the young were deliberately removed from the nipple, and ceased being emitted beyond about 80 days, some 5 or so days after the eyes open, when the young leave the pouch for substantial amounts of time. The spectrum of the call was similar at all ages within this 45 day period, and its peak frequency correlated closely with the best frequency in the adult quoll's ABR audiogram. At approximately 80 days of age the calls developed major low frequency components, similar to those measured in adult vocalizations, and the contributions of frequencies between 8-11 kHz waned in importance. The results indicate that the onset of hearing in quolls occurs at a relatively early time in the course of their development, but prior to this time the pouch-young emit characteristic isolation calls easily detectable by the mother.

Acoustic Stimulation↗
PubMed1996

Current therapy for Crigler-Najjar syndrome type 1: report of a world registry.

This study represents a multicenter survey on the management of patients with Crigler-Najjar syndrome (CNS) type 1. The aim of the survey was to find guiding principles for physicians in the care of these patients. Fifty-seven patients were included. At the time of inclusion, 21 patients had received a liver transplant (37%). The average age at transplantation was 9.1 +/- 6.9 years (range, 1-23 years); the age of the patients who had not been transplanted at the time of inclusion was 6.9 +/- 6.0 years (range, 0-23 years). Brain damage had developed in 15 patients (26%). Five patients died, and 10 are alive with some degree of mental or physical handicap. In 2 patients, ages 22 and 23 years, early signs of bilirubin encephalopathy could be reversed, in 1 by prompt medical intervention followed by liver transplantation and in the other by prompt liver transplantation. Seven patients underwent transplantation with some degree of brain damage at the time of the surgery; 1 of these died after retransplantation, 2 improved neurologically, and 4 remained neurologically impaired. The age of 8 patients with and 13 without brain damage at or before transplantation was 14.3 +/- 5.9 and 5.9 +/- 5.4 years (P < .01), respectively. Therapy of CNS type 1 consists of phototherapy (12 h/d), followed by liver transplantation. Phototherapy, although initially very effective, is socially inconvenient and becomes less efficient in the older age group, thus also decreasing compliance. Currently, liver transplantation is the only effective therapy. This survey shows that, in a significant number of patients, liver transplantation is performed after some form of brain damage has already occurred. From this, one must conclude that liver transplantation should be performed at a young age, particularly in situations in which reliable administration of phototherapy cannot be guaranteed.

Adolescent↗
PubMed1996

Controlled trial of nimodipine in amyotrophic lateral sclerosis.

Calcium channel blocking drugs antagonize excitatory amino acid receptor activation, decrease calcium entry into damaged neurons, and might help to slow or reverse amyotrophic lateral sclerosis (ALS). We enrolled 87 patients with ALS in a randomized, placebo-controlled, prospective, double-blind crossover study of nimodipine therapy. Monthly measures of isometric muscle strength and respiratory function compared the effects of drug and placebo. No difference in adverse events occurred in placebo vs drug-treated patients, but diarrhoea, nausea, and lightheadedness were more common with nimodipine. There was no significant difference in the rate of decline of pulmonary function or limb strength during treatment with drug or placebo. Nimodipine was ineffective in slowing the progress of ALS.

Amyotrophic Lateral Sclerosis↗
PubMed1996

Developing a subject-derived terminology to describe perceptions of chemicals in foods.

Risk perception may be influenced by a number of factors, such as unfamiliarity, lack of control, perceived consequences, and hazards being seen as catastrophic and having risk for future generations. Risk perception researchers have typically used such investigator-selected characteristics to assess hazards. In the first study reported here, the repertory grid method was used to elicit the terminology that subjects (n = 30) use to distinguish between 30 different chemicals. The data were submitted to generalized Procrustes analysis. The first principal axis of the resulting consensus plot separated the chemicals ranging from "poisonous or toxic," "harmful or dangerous," and "sounds negative" at one end, to "positive effect on health," "often present in food nowadays," and "sounds positive" at the other end. The second principal axis ranged from "familiar with or knowledge of" and "chemical" to "natural." A second study (n = 226) was carried out to look at the general validity of the results of the repertory grid interviews using a fixed questionnaire. The data were submitted to principal components analysis and internal preference mapping. The first principal component ranged from "safe" and "healthy" at one end, to "poisonous" and "harmful" at the other end. The chemicals also separated in terms of "familiar," "chemical," and "natural." All three methods of data collection and analysis yield essentially similar results.

Attitude↗
PubMed1996

What determines trust in information about food-related risks? Underlying psychological constructs.

Trust in risk information about food related-hazards may be an important determinant of public reactions to risk information. One of the central questions addressed by the risk communication literature is why some individuals and organizations are trusted as sources of risk information and others are not. Industry and government often lack public trust, whereas other sources (for example, consumer organizations, the quality media, medical doctors) are highly trusted. Problematically, previous surveys and questionnaire studies have utilized questions generated by the investigators themselves to assess public perceptions of trust in different sources. Furthermore, no account of the hazard domain was made. In the first study reported here, semistructured interviewing was used to elicit underpinning constructs determining trust and distrust in different sources providing food-related risk information (n = 35). In the second study, the repertory grid method was used to elicit the terminology that respondents use to distinguish between different potential food-related information sources (n = 35), the data being submitted to generalised Procrustes analysis. The results of the two studies were combined and validated in survey research (n = 888) where factor analysis indicated that knowledge in itself does not lead to trust, but that trusted sources are seen to be characterised by multiple positive attributes. Contrary to previous research, complete freedom does not lead to trust-rather sources which possess moderate accountability are seen to be the most trusted.

Adult↗
PubMed1996

X-linked immune dysregulation, neonatal insulin dependent diabetes, and intractable diarrhoea.

Four related male infants presented with neonatal diabetes mellitus, immune dysregulation with extremely high concentrations of immunoglobulin E, and intractable diarrhoea. They were all from one family, and all of them died. As far as is known this X-linked recessive disorder has not been described before. It is suggested that this is a new immunodeficiency in which type 2 T helper responses predominate.

Diabetes Mellitus, Type 1↗
PubMed1995

Novel bioemulsifiers from microorganisms for use in foods.

The main objective of this study was to test the range of microorganisms for production of extracellular, high molecular weight emulsifiers for potential use in foods. A standard emulsification assay developed specifically for assessing food emulsifiers was used to examine 24 extracellular microbial products from bacteria, yeasts and algae. Of the 24 products tested, nine had emulsification ability that was as good as and eight had emulsifying properties that were better than those of the commonly used food emulsifiers gum arabic and carboxymethylcellulose. The eight good producer organisms included the yeasts Candida utilis, Candida valida, Hansenula anomala, Rhodospiridium diobovatum and Rhodotorula graminis, the red alga Porphiridium cruentum, and the bacteria Klebsiella spp. and Acinetobacter calcoaceticus. Of these, C. utilis was selected for further study due to the excellent emulsification properties of its extracellular products and food-grade status of the organism. Crude preparations of the bioemulsifier from C. utilis exhibited low viscosity and had a carbohydrate content of over 80%. Preliminary trials showed that the bioemulsifier from this organism had potential for use in salad cream.

Acinetobacter calcoaceticus↗