PubMed Health⌕ Search

Biomedical subjects

S Healy

Publications and source records attributed to S Healy.

At least 19 recordsLinked to original sources
PubMed2005

Cytocompatibility of novel tin oxide thin films.

The capacity of tin oxide films to support cell growth was investigated. Three substrates were used for the test: glass coverslips, glass coverslips spin coated with tin oxide and commercially available 316 stainless steel. The wettabilities and surface roughness of the three surfaces were measured before seeding 3T3 fibroblasts onto the samples. The behaviour of the cells grown on the tin oxide was compared to the uncoated glass and the steel and results showed that the cell growth on tin oxide compared favourably with the other substrates. The surface wettability appeared to have the strongest effect on cell adhesion to tin oxide.

3T3 Cells↗
PubMed2005

Pseudocholinesterase polymorphism in an Irish population.

BACKGROUND: Pseudocholinesterase polymorphism, as an example of pharmacogenetics with important clinical implications, has been widely studied and documented. However, data on a sample Irish population is lacking. We sought to provide this. METHOD: In an assay involving Ellman's reaction, pseudocholinesterase activity, alone and with dibucaine or fluoride as an inhibitor, was quantified using propionylthiocholine iodide as substrate. RESULTS: Pseudocholinesterase activities of 1.13-12.71 U/ml (mean +/- SD 6.74 +/- 2.04 U/ml) showed a normal distribution among our 116 healthy, non-medicated volunteers, aged 11-80 years (30.7 +/- 10.5 years) and weighing 46-114.6 kg (66.8 +/- 11.4 kg). However, dibucaine numbers from an inhibition study yielded a trimodal pattern consistent with the hypothesis of two allelic genes. Using an established nomenclature, 92 (79.3%) of our volunteers were homozygous for the usual form of the enzyme (E1uE1u). Of the 13 genotyped as E1uE1a, it is possible that 3 were misclassified and are probably E1kE1a. Only one volunteer was homozygous for the atypical form of the enzyme, with activity of 1.13 U/ml and dibucaine and fluoride number of 18.2 and 82.8, respectively. CONCLUSION: The continuous variation in pseudocholinesterase activity and the trimodal pattern of dibucaine numbers are both in accord with observations in other population groups. Although dibucaine number yields a trimodal pattern, its use could lead to misclassification of some E1kE1a as E1uE1a.

Journal Article↗
PubMed2002

Tube feeding controversial patients: what do dietitians think?

The use of tube feeding in some patients can be controversial, however, few studies have investigated dietitians' opinions on this subject. A cross-sectional survey of 345 members the Irish Nutrition and Dietetic Institute was conducted using a self-administered, anonymous, postal questionnaire. A 44% response rate was achieved. Mean number of years qualified was 9.3 (8.4). Eighty-one per cent of responders were involved in initiating tube feeding in stroke patients, and 8.5% in discontinuing tube feeding in a patient in a persistent vegetative state (PVS). Nine per cent felt that their input had no influence on the care plan of the patient with dementia and 67% felt that the information given to families (or other decision makers) concerning tube feeding was inadequate. The majority of respondents favoured tube feeding fictitious stroke and cancer patients, but less than half favoured tube feeding a fictitious patient in a PVS or a patient with dementia. When given similar scenarios involving themselves, fewer dietitians wanted to be tube fed.

Contraindications↗
PubMed2001

Risk as social process: the end of 'the age of appealing to the facts'?

This paper utilises the notion of the risk society to argue that the ways in which technical practices, knowledge and rationality have become structured into governance are counter-productive and now instrumental to the proliferation of risk and destabilisation of governance. This problem is epitomised by how decisions have evolved to become a matter determined by 'facts' rather than by a determination of the community impact of outcomes and further compounded by the institutionally embedded blindness to wider social concerns that this entails. It is argued that what are required are processes integrating 'factual' technical and 'value-laden' societal concerns and avenues for this and their ramifications are elaborated and explored. Central to such developments will be a democratisation of technical practices and the institutions in which they are embedded. The broader political implications of these developments are examined and found to involve a radical extension of democracy involving an extensive reshaping of the topography of governance.

Decision Making↗
PubMed2000

Force level and strain patterns during bilateral mandibular osteodistraction.

PURPOSE: Recent reports have demonstrated that device orientation is important during mandibular distraction osteogenesis. The purpose of this study was to evaluate the force level and strain patterns on the mandible during bilateral osteodistraction with devices oriented either parallel to the body of the mandible or parallel to the sagittal axis of distraction. MATERIALS AND METHODS: Five unembalmed human cadaver mandibles were placed in a specially designed apparatus for stabilization of the proximal segments during distraction. A force transducer was attached to the lateral aspect of the inferior ramus, and strain gauges were attached to the mandibular bone segments proximal and distal to the distraction device. Lateral force and bone strains were then measured at 5 and 10 mm of distraction. Osteodistraction proceeded first with the devices placed parallel to the mandibular body, then parallel to the axis of distraction. RESULTS: Significantly greater lateral forces were seen when the devices were oriented parallel to the mandibular body. With this device orientation, increased tensile strains were seen at the labial symphysis and medial ramus, and increased compressive strains were found at the lingual symphysis and lateral ramus. However, when the devices were oriented parallel to the axis of distraction, the forces and strains were not detected. CONCLUSIONS: The results suggest that device orientation has important biomechanical effects on lateral forces and strain patterns during mandibular osteodistraction.

Adult↗
PubMed1998

The maize retinoblastoma protein homologue ZmRb-1 is regulated during leaf development and displays conserved interactions with G1/S regulators and plant cyclin D (CycD) proteins.

Recent discoveries of plant retinoblastoma (Rb) protein homologues and D-type cyclins suggest that control of the onset of cell division in plants may have stronger parallels with mammalian G1/S controls than with yeasts. In mammals, the Rb protein interacts specifically with D-type cyclins and regulates cell proliferation by binding and inhibiting E2F transcription factors. However, the developmental role of Rb in plants and its potential interaction with cell cycle regulators is unknown. We show that the maize Rb homologue ZmRb-1 is temporally and spatially regulated during maize leaf development. ZmRb-1 is highly expressed in differentiating cells, but almost undetectable in proliferating cells. In vitro, both ZmRb-1 and human Rb bind all classes of plant D-type cyclins with the involvement of a conserved N-terminal Leu-x-Cys-x-Glu (LxCxE) Rb-interaction motif. This binding is strongly reduced by mutation of the conserved Cys-470 of ZmRb-1. ZmRb-1 binds human and Drosophila E2F, and inhibits transcriptional activation of human E2F. We also show that ZmRb-1 is a good in vitro substrate for all human G1/S protein kinases. The functional conservation of proteins that control the G1/S transition in mammals and plants points to the existence of plant E2F homologues. We conclude that evolution of Rb and cyclin D proteins occurred after separation of the fungi from the higher eukaryotic lineage, but preceded the divergence of plant and animal kingdoms.

Arabidopsis↗
PubMed1997

Interactions of a subassembly of the herpes simplex virus type 1 helicase-primase with DNA.

The UL5, UL8, and UL52 genes of herpes simplex virus type 1 encode a multisubunit assembly that possesses primase, DNA helicase, and DNA-dependent nucleoside triphosphatase activities. A subassembly consisting of the UL5 and UL52 gene products retains these activities. The nucleoside triphosphatase activity of the UL5/UL52 subassembly is strongly stimulated by both homo- and heteropolymeric single-stranded DNA. Double-stranded DNA has little ability to stimulate the ATPase activity. The subassembly binds both double and single-stranded DNA. Nucleotides are not required for DNA-binding. The minimum length of single-stranded DNA that is bound and that stimulates enzymatic activity is about 12 nucleotides. The kinetic parameters of the ATPase activity of the subassembly are affected by the length of the oligonucleotide coeffector. The Km decreases as the coeffector length is increased up to a length of about 20 nucleotides and then remains independent of coeffector length. The first order rate constant for ATPase activity exhibits a quasihyperbolic dependence on the length of the DNA coeffector and is maximal for coeffectors of 20 nucleotides and longer.

Adenosine Triphosphatases↗
PubMed1995

A new clinical classification for hospital prognosis of unstable angina pectoris.

Unstable angina represents a heterogeneous spectrum of clinical entities between chronic stable angina and acute myocardial infarction. To facilitate prognostication of in-hospital outcome, we prospectively tested on a priori unstable angina classification scheme based on information available at the time of acute presentation. Prospective database enrollment at the time of emergency room presentation was performed and patients were classified into 1 of the following categories: class IA, acceleration of previous exertional angina without electrocardiographic (ECG) changes; class IB, acceleration of previous exertional angina with ECG changes; class II, new-onset exertional angina; class III, new-onset rest angina; class IV, protracted rest angina with ECG changes. The study consisted of 1,387 consecutive patients with unstable angina. Baseline demographics and aggregate in-hospital major cardiac event rates were recorded (myocardial infarction, refractory angina, and death). There was a significant increasing trend in cardiac events from class I to IV (p < 0.0001). Class IA patients had the lowest aggregate event rate at 2.7% (p = 0.0005). Paired chi-square tests of adjacent categories showed no differences in event rates for class IB and II (p = 0.3). A significantly higher rate of adverse events was seen for class III patients (20.1%, p < 0.0001). Class IV patients demonstrated the highest rate of in-hospital adverse events (42.8%, p < 0.0001). We conclude that this easily deduced, universally applicable categorization of unstable angina is highly prognostic of in-hospital adverse cardiac events and hence could have potential use for triage decisions regarding hospital admission and intensity of therapy.

Aged↗
PubMed1995

Steroid induced osteoporosis: an opportunity for prevention?

OBJECTIVE: To determine the frequency with which osteoporosis prophylaxis is given to corticosteroid treated hospital inpatients. METHODS: All patients receiving systemic corticosteroids in a large teaching hospital over a three month period were identified through routine prescription monitoring by hospital ward pharmacists. Coprescription of antiosteoporotic therapy was recorded, along with other relevant details such as steroid dose, actual, or intended duration of therapy, and indication for therapy. RESULTS: Corticosteroids were prescribed to 214 patients over the study period, giving an average rate of 2.5 new prescriptions each day. Indications included: chest disease (n = 84; 39.2%), cancer (n = 17; 7.9%), inflammatory bowel disease (n = 16; 7.5%), rheumatoid arthritis/connective tissue disease (n = 16; 7.5%), and renal diseases (n = 7; 3.3%). One hundred and twelve patients (52.3%) were receiving short term steroid therapy (less than four months); 66 (37%) were receiving medium/long term steroid therapy (four months or more). In 36 cases (16.8%) the duration of therapy was unknown. Only 12 of the 214 patients (5.6%) received any form of osteoporosis prophylaxis. The prevalence of prophylaxis was similarly low in postmenopausal women (six of 93; 6.4%) and in patients receiving high dose long term steroid therapy (two of 25; 8%). CONCLUSIONS: Systemic corticosteroids are used frequently in hospital practice for a wide range of indications, but few patients receive co-prescription of prophylaxis against osteoporosis. This is true even in high risk groups such as postmenopausal women and those on high dose long term steroid therapy. Identification of individuals by the mechanism used in this study provides an opportunity by which all corticosteroid treated patients could be detected and offered osteoporosis prophylaxis before serious loss of bone density has occurred.

Adolescent↗
PubMed1994

Decreased hedonic responsiveness during a brief depressive mood swing.

Female volunteers completed the Fawcett-Clark Pleasure Capacity Scale (FCPCS) and rated the pleasantness and desirability of a taste stimulus (cheese), before and during a depressive mood swing. Mood change was induced by reading negative self-referent statements, with additional 'booster' periods of mood induction to prolong the duration of the mood swing. The mood induction procedure (MIP) caused a decrease in contentment and alertness, as derived from a set of visual analogue mood scales, and also decreased hedonic capacity, as measured by responses to the taste stimulus and by the FCPCS. No changes on any measure were shown by a control group who read an equivalent set of positive self-referent statements. Prior to the MIP, there were no significant correlations between mood measures and hedonic measures, or between taste responses and the FCPCS. However, there were significant correlations between the size of the changes in these various measures following the depressive MIP. The results suggest that hedonic capacity is responsive to acute depressive mood swings.

Adult↗
PubMed1994

Auditory specialization in deaf children. Aural and cognitive interactions.

Hemispheric specialization in the brain has become a focus of study in recent years in an effort to better understand language acquisition and use in deaf children. To test the hypothesis that better-ear hearing acuity in severely hearing-impaired children will interact differentially with cognitive performance because of hemispheric influence, 27 children with bilateral, severe to profound hearing loss were divided into two comparison groups and a control group and were given a series of cognitive tasks of increasing difficulty. The authors conclude that hemispheric interactions may take place and affect cognitive performance in ways predictable from hemispheric-specialization theory and hearing ability. We offer suggestions for the focus of future research on this question.

Auditory Perception↗
PubMed1992

Role of psychosocial risk factors in work-related low-back pain.

The experience of low-back pain and its psychosocial associates were directly compared among sufferers drawn from three populations, a blue-collar working group, a white-collar working group, and a patient group. Sufferers drawn from the patient population revealed the expected psychological disturbance. There was no evidence of such involvement for sufferers still at work. Disability resulting from low-back pain was positively linearly related to severity of pain for sufferers drawn from working groups, irrespective of psychological disturbance. For patients, on the other hand, the presence of psychological disturbance modified the relationship between severity and disability such that no simple linear relationship existed between the two variables. Work dissatisfaction was not found to be related to the presence of, and did not account for disability resulting from, low-back pain in working subjects.

Adult↗
PubMed1982

Mutagens from the cooking of food. II. Survey by Ames/Salmonella test of mutagen formation in the major protein-rich foods of the American diet.

The formation of mutagens in the major cooked protein-rich foods in the US diet was studied in the Ames Salmonella typhimurium test. The nine protein-rich foods most commonly eaten in the USA--ground beef, beef steak, eggs, pork chops, fried chicken, pot-roasted beef, ham, roast beef and bacon--were examined for their mutagenicity towards S. typhimurium TA1538 after normal 'household' cooking (deep frying, griddle/pan frying, baking/roasting, broiling, stewing, braising or boiling of 100-475 degrees C). Well-done fried ground beef, beef steak, ham pork chops and bacon showed significant mutagen formation. For chicken and beef steak high-temperature broiling produced the most mutagenicity, followed by baking/roasting and frying. Stewing, braising and deep frying produced little mutagen. Eggs and egg products produced mutagens only after cooking at high temperatures (the yolk to a greater extent than the white). Commercially cooked hamburgers showed a wide range of mutagenic activity. We conclude that mutagen formation following cooking of protein-containing foods is a complex function of food type, cooking time and cooking temperature. It seems clear that all the major protein-rich foods if cooked to a well-done state on the griddle (eggs only at temperatures above 225 degrees C) or by broiling will contain mutagens detectable by the Ames/Salmonella assay. This survey is a step towards determining whether any human health hazard results from cooking protein-rich foods. Further testing in both short- and long-term genotoxicity bioassays and carcinogenesis assays are needed before any human risk extrapolations can be made.

Animals↗
PubMed1982

Mutagens from the cooking of food. III. Survey by Ames/Salmonella test of mutagen formation in secondary sources of cooked dietary protein.

A survey of mutagen formation during the cooking of a variety of protein-rich foods that are minor sources of protein intake in the American diet is reported (see Bjeldanes, Morris, Felton et al. (1982) for survey of major protein foods). Milk, cheese, tofu and organ meats showed negligible mutagen formation except following high-temperature cooking for long periods of time. Even under the most extreme conditions, tofu, cheese and milk exhibited fewer than 500 Ames/Salmonella typhimurium revertants/100 g equivalents (wet weight of uncooked food), and organ meats only double that amount. Beans showed low mutagen formation after boiling and boiling followed by frying (with and without oil). Only boiling of beans followed by baking for 1 hr gave appreciable mutagenicity (3650 revertants/100g equivalents). Seafood samples gave a variety of results: red snapper, salmon, trout, halibut and rock cod all gave more than 1000 revertants/100 g wet weight equivalents when pan-fried or griddle-fried for about 6 min/side. Baked or poached rock and deep-fried shrimp showed no significant mutagen formation. Broiled lamb chops showed mutagen formation similar to that in red meats tested in the preceding paper: 16,000 revertants/100 g equivalents. These findings show that as measured by bioassay in S. typhimurium, most of the foods that are minor sources of protein in the American diet are also minor sources of cooking-induced mutagens.

Animals↗
PubMed1981

Mutagens from the cooking of food. I. Improved extraction and characterization of mutagenic fractions from cooked ground beef.

Ground beef was fried at 200 degrees C (392 degrees F) to a well-done, non-charred state, and the extracted organic base fraction was found to be highly mutagenic in Salmonella strain TA1538 (6300 revertants/100 g equivalent, gE, fresh weight). The neutral and acidic extracts showed no mutagenic activity in any of the 5 standard strains of Salmonella. A new procedure based upon extraction and protein precipitation with acetone is described, which is simpler and more efficient than previously described methods. The organic base fraction was mutagenic only in Salmonella strains TA1537, TA1538, and TA98, all sensitive to frameshift mutations. Strains sensitive to base-substitution mutations showed no activity. Metabolic activation was an absolute requirement for mutagenesis; however cell toxicity was decreased by the presence of S9 activation mixture. After normal cooking, more than 20 times as much mutagenic material remained in the meat as was recovered in the pan grease and vapors. The results confirm that mutagens are formed under conventional frying conditions, and show that mutagen can be isolated by an improved extraction method.

Animals↗
PubMedDate not supplied

Mutagenic and toxic activity of environmental effluents from underground coal gasification experiments.

Using bacterial bioassays, we have screened for the presence of mutagens and toxins in extracts from groundwater, and in tar from product gas, at the sites of two Lawrence Livermore National Laboratory (LLNL) in situ experiments: Hoe Creek II and Hoe Creek III. The sites exhibited different potential biological hazards, suggesting that different gasification processes may represent different human health concerns. We found that mutagens are present in groundwater, persist for at least 2 yr after gasification has been terminated, and show a change in activity with time-possibly in parallel with changes in chemical composition. Preliminary evidence suggests that the mutagens in groundwater are quinoline and aniline derivatives, while the toxins in groundwater may be phenolic compounds. In tar from the product gas, the organic bases and neutrals were found to be genotoxic in both bacterial and mammalian cells; the neutral compounds appear to be the major mutagenic health hazards. Neutral compounds constitute most of the tar (85-97 wt%) and were mutagenic in both the bacterial and mammalian cell assays. Tar in the gas stream may be a problem for the aboveground environment if gas escapes through fractures in the overburden. Because it is mutagenic and induces chromosomal damage to mammalian cells, the tar may represent a disposal problem as well. However, it is difficult to assess tar quantitatively as a health hazard because its mutagenic activity is low, possibly due to contaminants in the neutral fraction that act to suppress mutagenicity.

Animals↗