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Biomedical subjects

M Ryan

Publications and source records attributed to M Ryan.

At least 55 records · Page 3Linked to original sources
PubMed2001

Cost of treating acute myocardial infarction in an Irish teaching hospital.

Recent figures indicate that there are approximately 6,500 patients admitted to hospital following acute myocardial infarction (AMI) in Ireland each year. As hospital admission is frequently the most expensive component of healthcare we determined the costs associated with treatment of AMI in a teaching hospital. The costing evaluation was from the hospital perspective and the strategy used was a micro-costing detailed collection of resources used. The average cost of hospital admission for the treatment of AMI was Pound Sterling 3,976. The average cost per day was calculated at Pound Sterling 501. Approximately 50% of hospital costs were associated with ward costs. Procedures accounted for 35% of costs whereas medications contributed just 7% of total costs.

Aged↗
PubMed2000

The platelet integrin alpha IIbbeta 3 has an endogenous thiol isomerase activity.

Integrins are cysteine-rich heterodimeric cell-surface adhesion molecules that alter their affinity for ligands in response to cellular activation. The molecular mechanisms involved in this activation of integrins are not understood. Treatment with the thiol-reducing agent, dithiothreitol, can induce an activation-like state in many integrins suggesting that cysteine-cysteine dithiol bonds are important for the receptor's tertiary structure and may be involved in activation-induced conformational changes. Here we demonstrate that the platelet-specific integrin, alpha(IIb)beta(3), contains an endogenous thiol isomerase activity, predicted from the presence of the tetrapeptide motif, CXXC, in each of the cysteine-rich repeats of the beta(3) polypeptide. This motif comprises the active site in enzymes involved in disulfide exchange reactions, including protein-disulfide isomerase (EC ) and thioredoxin. Intrinsic thiol isomerase activity is also observed in the related integrin, alpha(v)beta(3), which shares a common beta-subunit. Thiol isomerase activity within alpha(IIb)beta(3) is time-dependent and saturable, and is inhibited by the protein-disulfide isomerase inhibitor, bacitracin. Furthermore, this activity is calcium-sensitive and is regulated in the EDTA-stabilized conformation of the integrin. This novel demonstration of an enzymatic activity associated with an integrin subunit suggests that altered thiol bonding within the integrin or its substrates may be locally modified during alpha(IIb)beta(3) activation.

Amino Acid Sequence↗
PubMed2000

Surface expression of glycoprotein ib alpha is dependent on glycoprotein ib beta: evidence from a novel mutation causing Bernard-Soulier syndrome.

Bernard-Soulier syndrome is a rare bleeding disorder caused by a quantitative or qualitative defect in the platelet glycoprotein (GP) Ib-IX-V complex. The complex, which serves as a platelet receptor for von Willebrand factor, is composed of 4 subunits: GPIb alpha, GPIb beta, GPIX, and GPV. We here describe the molecular basis of a novel form of Bernard-Soulier syndrome in a patient in whom the components of the GPIb-IX-V complex were undetectable on the platelet surface. Although confocal imaging confirmed that GPIb alpha was not present on the platelet surface, GPIb alpha was readily detectable in the patient's platelets. Moreover, immunoprecipitation of plasma with specific monoclonal antibodies identified circulating, soluble GPIb alpha. DNA-sequence analysis revealed normal sequences for GPIb alpha and GPIX. There was a G to A substitution at position 159 of the gene encoding GPIb beta, resulting in a premature termination of translation at amino acid 21. Studies of transient coexpression of this mutant, W21stop-GPIb beta, together with wild-type GPIbalpha and GPIX, demonstrated a failure of GPIX expression on the surface of HEK 293T cells. Similar results were obtained with Chinese hamster ovary alpha IX cells, a stable cell line expressing GPIbalpha that retains the capacity to re-express GPIX. Thus, we found that GPIbbeta affects the surface expression of the GPIb-IX complex by failing to support the insertion of GPIb alpha and GPIX into the platelet membrane. (Blood. 2000;96:532-539)

Animals↗
PubMed2000

The Effects of Radiofrequency Electromagnetic Radiation on the Adhesion Behavior of Aqueous Suspensions.

The effect of radiofrequency treatment on the adhesion behavior of amidine and carboxylated polystyrene latexes was investigated. The isoelectric points pH(IEP) of copper and zinc were initially measured as 9.4 and 9.5, respectively, using a technique proposed by N. Kallay, Z. Torbic, M. Golic, and E. Matijevic [J. Phys. Chem. 95, 7028 (1991)] based on the attachment of charged colloids to metallic surfaces in an aqueous medium. Statistical analysis showed that the technique was repeatable with a coefficient of variation less than 6% and an accuracy greater than 95%. The effect of a radiofrequency signal (27 MHz) on adhesion behavior was evaluated and it was found that there was reduced attachment at pH values when the colloid and metallic surface were oppositely charged and enhanced attachment between similarly charged particles. It is proposed that this is due to a reduction in the surface potential of the charged particles due to thickening of the adsorbed layer by hydrogen and hydroxyl ions. Copyright 2000 Academic Press.

Journal Article↗
PubMed2000

Therapeutic dilemma: the use of anticonvulsants in HIV-positive individuals.

ARTICLE ABSTRACT: The concurrent use of anticonvulsants and antiretrovirals is a poorly studied area that poses a therapeutic dilemma for the clinician caring for HIV-positive patients requiring both classes of medications. Anticonvulsants and antiretrovirals may interact through multiple mechanisms including competition for protein binding, enhanced or reduced liver metabolism, and increased viral replication. The authors present many of the challenges faced by clinicians caring for HIV-positive patients who may require anticonvulsant therapy.

Anti-HIV Agents↗
PubMed2000

The veil of experience: do consumers prefer what they know best?

There is growing interest from health policy makers in eliciting consumer preferences for health care services. This is particularly the case when assessing the likely impact of innovations. Some people may be wary of innovations because they prefer the service they have previously experienced. Consumer preferences for an existing and a hypothetical new bowel cancer testing programme were measured using a discrete choice experiment questionnaire. The results showed that consumers had a statistically significant preference for the existing service (status quo) when all other factors remained constant. It suggested that consumers make decisions under a 'veil of experience'. Possible explanations for this result include the endowment effect, status quo bias and loss aversion. Future evaluations of health service innovation should be aware of this tendency to favour the status quo.

Attitude to Health↗
PubMed2000

Oligomeric status of the dihydropyridine receptor in aged skeletal muscle.

A prominent feature of aging is represented by a decrease in muscle mass and strength. Abnormalities in Ca2+ -regulatory membrane complexes are involved in many muscular disorders. In analogy, we determined potential age-related changes in a key component of excitation-contraction coupling, the dihydropyridine receptor. Immunoblotting of the microsomal fraction from aged rabbit muscle revealed a drastic decline in the voltage-sensing alpha1-subunit of this transverse-tubular receptor, but only marginally altered expression of its auxiliary alpha(2)-subunit and the Na+/K+ -ATPase. A shift to slower fibre type characteristics was indicated by an age-related increase in the slow calsequestrin isoform. Chemical crosslinking analysis showed that the triad receptor complex has a comparable tendency of protein-protein interactions in young and aged muscles. Hence, a reduced expression and not modified oligomerization of the principal dihydropyridine receptor subunit might be involved in triggering impaired triadic signal transduction and abnormal Ca2+ -homeostasis resulting in a progressive functional decline of skeletal muscles.

Aging↗
PubMed2000

Relation between circadian patterns in levels of circulating lipoprotein(a), fibrinogen, platelets, and related lipid variables in men.

BACKGROUND: A correlation has been reported between lipoprotein(a) [Lp(a)] concentration and risk for coronary artery disease. High concentrations of Lp(a) might be markers for vascular or tissue injury or might be associated with other genetic or environmental factors that can cause acute myocardial infarction. METHODS: We measured the circadian characteristics of circulating Lp(a), fibrinogen, platelets, cholesterol, triglycerides, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol for a group of adult male volunteers who had no clinical symptoms. We obtained samples every 3 hours around the clock to assess the normal degree of variation within a 24-hour period and to test for similarities in circadian patterns and correlations with level of Lp(a). RESULTS: Each variable displayed a highly significant circadian rhythm. Lp(a), fibrinogen, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol peaked in the morning. Cholesterol and platelets peaked in the late afternoon, and triglycerides peaked in the evening. CONCLUSIONS: Although peak levels of Lp(a) and fibrinogen coincide with reported morning peak frequencies of myocardial infarction and stroke, the platelet peak appears to coincide with late afternoon peak frequencies of sudden cardiac death and fatal stroke. The data suggest that proper timing of single samples may improve the usefulness and accuracy of diagnosis, risk assessment, and therapy.

Aged↗
PubMed2000

Using discrete choice modelling in priority setting: an application to clinical service developments.

Limited resources for health care means that techniques are required to aid the process of priority setting. This paper represents one of the first attempts to use discrete choice modelling (DCM) within the area of priority setting. It is shown how the technique can be used to estimate cost per unit of benefit ratios for competing clinical service developments. Integer programming is proposed as a method to be used, alongside DCM, to help policy makers select the optimal combination of clinical service developments within a given budget. The technique is also shown to be internally valid and internally consistent. It is argued that DCM is a potentially useful technique to be used within the area of priority setting more generally. However, further work is required to address methodological issues around the technique.

Adult↗
PubMed2000

The role of a high-dependency unit in a regional obstetric hospital.

The aim of our study was to review a series of critically ill patients admitted to a high-dependency unit (HDU) in a regional obstetric centre, to assess our HDU utilisation rate and to determine the indications for and rate of transfer to an intensive care unit (ICU) in a tertiary referral centre. A 4-year retrospective review of case notes and HDU/ICU registers was performed. One hundred and twenty-three patients were admitted to the HDU in the 2 years following its inception, representing 1.02% of all deliveries. Obstetric complications accounted for 81.3% of admissions. Seventeen patients were admitted to an ICU during the study period; 12 (0.08%) were transferred before and five (0.04%) after the development of HDU facilities (p = 0.25). The advantages of a HDU within this setting include the concurrent availability of expert obstetric care and critical care management, the avoidance of the hazards of emergency transport and improved continuity of antenatal and postnatal care.

Adult↗
PubMed2000

Comparing different methods of assessing body composition in end-stage renal failure.

BACKGROUND: Accurate measurement of nutritional status in patients with end-stage renal disease is important because of its clear association with prognosis. Total body water (TBW) has additionally been recently recognized as an independent prognostic value because of its relationship with hypertension and cardiac morbidity. The current study was designed to assess the utility of surrogate markers of nutritional state and TBW in patients with end-stage renal disease. METHODS: Fifty-four patients with renal disease were studied. TBW obtained using the deuterium dilution technique was compared with estimates derived from anthropometric measures of TBW, including 58% body weight, Watson equations, and bioelectrical impedance analysis (BIA). Anthropometrically derived fat-free mass (FFM) was compared with BIA-derived estimates. Total body nitrogen (TBN) measurements were correlated with TBW estimates and BIA-derived resistance. RESULTS: TBW was significantly underestimated by the Watson equation (mean difference, -1.751 L, P = 0.01) and the 58% body weight approximation significantly overestimated it (mean difference, 1.792 L, P = 0.04). The Kushner BIA estimation of TBW did not significantly differ from that of the gold standard determined from D2O dilution (mean difference, -1.221 L, P = 0.12) and was also the method that showed the best agreement with the D2O estimate. However, the limits of agreement were large. Accurate prediction equations for FFM (FFM = -21.768 + 0.001 x ht2 + 6630.669 x 1/R + 0.312 x wt, R2 = 0.95) and TBN (TBN = -668.324 - 3.963 x age + 10.133 x wt + 0. 045 x ht2 + 32141.457 x 1/R, R2 = 0.91) were derived from BIA obtained resistance. CONCLUSIONS: The estimation of TBW varies significantly depending on the method of calculation. BIA is the most accurate surrogate marker for the measurement of both TBW and other parameters of body composition.

Adipose Tissue↗
PubMed2000

Pain management: an organizational commitment.

Although much has been done to promote pain assessment and management, pain remains a major, yet largely preventable, public health problem in the United States. A strategy that has been proposed to assure optimal pain management is the development of formal means within institutions to evaluate pain management practices and foster improved outcomes. In response to a pain-related patient care problem, South Nassau Communities Hospital recognized the need to undertake more formal methods for managing patients with acute, chronic, and cancer pain. A Pain Management Task Force was charged with the development of a comprehensive pain management program. Its efforts to date and plans for the future position this institution as ready for the Joint Commission for the Accreditation of Healthcare Organizations' pain assessment and management standards that were introduced in 2000.

Hospitals, Community↗
PubMed2000

Acupressure and prevention of nausea and vomiting during and after spinal anaesthesia for caesarean section.

The efficacy of acupressure at the P6 point in the prevention of nausea and vomiting during and after Caesarean section was studied. A double-blind, randomized controlled study of acupressure vs placebo was designed. Ninety-four patients scheduled for Caesarean section were included. The anaesthetic technique and postoperative analgesia were standardized. The use of acupressure reduced the incidence of nausea or vomiting from 53% to 23% compared with placebo (95% confidence interval (CI) 0.34-0.25; P = 0.002) during the operation and from 66% to 36% compared with placebo (95% CI 0.34-0.19; P = 0.003) after the operation. Other variables were similar between the groups.

Acupressure↗
PubMed2000

Trade-offs between location and waiting times in the provision of health care: the case of elective surgery on the Isle of Wight.

BACKGROUND: Recent UK government documents have stated that, within the National Health Service, consumers should be more involved in decision-making. This study considered the technique of discrete choice conjoint analysis (DCCA) for eliciting community views regarding the importance of reducing waiting times. More specifically, the study aimed to establish whether residents living on the Isle of Wight are prepared to travel to the mainland for elective surgery where waiting times are shorter but travel costs may be greater, and, further, if residents are willing to travel, what reduction in waiting time and increase in travel costs would be acceptable. METHODS: A DCCA questionnaire was sent to a random sample of 1,000 individuals living on the Isle of Wight. RESULTS: Seventy-eight per cent of respondents were willing to travel to the mainland for elective surgery. Of these, 48 per cent always chose the mainland and 30 per cent traded between island and mainland, depending on the levels of waiting time and travel costs. Whereas 'traders' preferred the Isle of Wight, they would forgo their preferred location if waiting times were reduced by at least 3.9 months, and they were willing to pay over 12 for a 1 month reduction in waiting time. Different combinations of waiting time reductions and travel cost increases that were acceptable to traders were estimated. CONCLUSIONS: Carrying out elective surgery on the mainland offers the potential to reduce waiting lists for island residents. The majority of respondents would be willing to travel to the mainland. However, one-fifth of respondents were not willing to travel to the mainland for elective surgery. The preferences of this group are important in policy decisions. More generally, the paper demonstrates the potential application of DCCA to public health issues.

Adolescent↗