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Biomedical subjects

M O'Brien

Publications and source records attributed to M O'Brien.

At least 37 records · Page 2Linked to original sources
PubMed2003

Patients' health-related quality-of-life and health state values for motor neurone disease/amyotrophic lateral sclerosis.

Motor neurone disease (MND) has a severe impact on patient quality of life, especially in later stages of the disease. This study assesses the health-related quality of life (HRQL) of MND patients, and for the first time elicits health state values from patients for their present health state. A structured interview was conducted with 77 patients. Patients completed a disease specific health status measure (ALSAQ-40), a generic health status measure (EuroQol EQ-5D), a visual analogue scale (VAS) and a standard gamble (SG) exercise. The ALSAQ-40 was sensitive to disease severity. Patients' mean VAS rating of their own health ranged from 0.74 for stage 1 (early) disease severity (n = 15), to 0.37 for stage 4 (late stage) disease severity (n = 19). Utilities elicited via SG varied from a mean of 0.79 for stage 1 disease severity to a mean of 0.45 for stage 4 disease severity. The EQ-5D derived single index ranged from a mean of 0.63 for stage 1 disease severity to a mean of -0.01 for stage 4 disease severity. This study demonstrates that it is feasible and practical to obtain health state values from MND patients and it provides evidence that patients place a high value on their HRQL, even in cases where health status is very poor.

Adult↗
PubMed2003

Inherited thrombotic tendency in a pedigree with antithrombin La Rochelle (N405K) and factor V Leiden.

An Irish pedigree with a strong thrombotic tendency, due to the novel association of antithrombin La Rochelle (N405K) and factor V Leiden is described. Thromboses occurred at a median age of 16 years in four family members, carrying both mutant alleles. Molecular diagnosis was facilitated by the creation of an additional restriction enzyme site (Mnl1) in exon 6 of the antithrombin gene. Both the genes for antithrombin and factor V are located at chromosome 1q23. The molecular data and phenotypic behaviour in this family are strongly suggestive of allelic co-segregation of the mutant alleles.

Adolescent↗
PubMed2003

Unintentional and undetermined firearm related deaths: a preventable death analysis for three safety devices.

OBJECTIVE: To determine the proportion of unintentional and undetermined firearm related deaths preventable by three safety devices: personalization devices, loaded chamber indicators (LCIs), and magazine safeties. A personalized gun will operate only for an authorized user, a LCI indicates when the gun contains ammunition, and a magazine safety prevents the gun from firing when the ammunition magazine is removed. DESIGN: Information about all unintentional and undetermined firearm deaths from 1991-98 was obtained from the Office of the Chief Medical Examiner for Maryland, and from the Wisconsin Firearm Injury Reporting System for Milwaukee. Data regarding the victim, shooter, weapon, and circumstances were abstracted. Coding rules to classify each death as preventable, possibly preventable, or not preventable by each of the three safety devices were also applied. RESULTS: There were a total of 117 firearm related deaths in our sample, 95 (81%) involving handguns. Forty three deaths (37%) were classified as preventable by a personalized gun, 23 (20%) by a LCI, and five (4%) by a magazine safety. Overall, 52 deaths (44%) were preventable by at least one safety device. Deaths involving children 0-17 (relative risk (RR) 3.3, 95% confidence interval (CI) 2.1 to 5.1) and handguns (RR 8.1, 95% CI 1.2 to 53.5) were more likely to be preventable. Projecting the findings to the entire United States, an estimated 442 deaths might have been prevented in 2000 had all guns been equipped with these safety devices. CONCLUSION: Incorporating safety devices into firearms is an important injury intervention, with the potential to save hundreds of lives each year.

Adolescent↗
PubMed2002

Generation of noninductive current by electron-Bernstein waves on the COMPASS-D Tokamak.

Electron-Bernstein waves (EBW) were excited in the plasma by mode converted extraordinary (X) waves launched from the high field side of the COMPASS-D tokamak at different toroidal angles. It has been found experimentally that X-mode injection perpendicular to the magnetic field provides maximum heating efficiency. Noninductive currents of up to 100 kA were found to be driven by the EBW mode with countercurrent drive. These results are consistent with ray tracing and quasilinear Fokker-Planck simulations.

Journal Article↗
PubMed2002

Molecular analysis of the stylar-expressed Solanum chacoense small asparagine-rich protein family related to the HT modifier of gametophytic self-incompatibility in Nicotiana.

Gametophytic self-incompatibility (GSI) systems involving the expression of stylar ribonucleases have been described and extensively studied in many plant families including the Solanaceae, Rosaceae and Scrophulariaceae. Pollen recognition and rejection is governed in the style by specific ribonucleases called S-RNases, but in many self-incompatibility (SI) systems, modifier loci that can modulate the SI response have been described at the genetic level. Here, we present at the molecular level, the isolation and characterization of two Solanum chacoense homologues of the Nicotiana HT modifier that had been previously shown to be necessary for the SI reaction to occur in N. alata (McClure et al., 1999). HT homologues from other solanaceous species have also been isolated and a phylogenetic analysis reveals that the HT genes fall into two groups. In S. chacoense, these small proteins named ScHT-A and ScHT-B are expressed in the style and are developmentally regulated during anthesis identically to the S-RNases as well as following compatible and incompatible pollination. To elucidate the precise role of each HT isoform, antisense ScHT-A and RNAi ScHT-B lines were generated. Conversion from SI to self-compatibility (SC) was only observed in RNAi ScHT-B lines with reduced levels of ScHT-B mRNA. These results confirm the role of the HT modifier in solanaceous SI and indicate that only the HT-B isoform is directly involved in SI.

Amino Acid Sequence↗
PubMed2002

Free radial forearm adipofascial flaps raised through limited incisions.

Free radial forearm adipofascial flaps were used for limb reconstruction in four cases. The flaps were harvested through limited skin incisions with the aid of lighted retractors. The mean surface area was 96 cm(2). The donor sites and the transferred tissue healed satisfactorily in all cases. Although the dissection through limited incisions is slightly awkward and prolongs the operating time, the technique offers significant benefits in terms of donor-site morbidity and aesthetics.

Adolescent↗
PubMed2002

The effect of spectra on calibration and measurement with mammographic ionization chambers.

Mammographic imaging uses x-ray tubes with molybdenum, rhodium, or tungsten anodes with the produced bremsstrahlung filtered by thin sheets of molybdenum, rhodium, or aluminum. The National Institute of Standards and Technology, the Accredited Dosimetry Calibration Laboratories, and several manufacturers offer calibrations of mammography ionization chambers with reference x-ray beams with different radiation qualities in the range 23-40 kVp. The energy response of ten commercially available chambers was determined for these reference radiation qualities using the Attix variable-length free-air chamber. The evaluated chambers are designed with thin entrance windows of varying thickness and composition. The chambers show variation in their air kerma response as a function of beam radiation quality. This response with beam radiation quality may affect the measurement of clinical beam half value layer (HVL) and the determination of the mean glandular dose. The combined effect of the chamber's energy dependence and HVL measurement affects the mean glandular dose calculation resulting in differences ranging from -1.8% to +2.5%.

Calibration↗
PubMed2001

Ventriculitis complicating use of intraventricular catheters in adult neurosurgical patients.

Ventriculitis is a serious complication of intraventricular catheter (IVC) use, with rates of IVC-related infections ranging from 0% to 45% and gram-positive organisms predominating. We prospectively analyzed ventriculostomy-related infections occurring among 157 adult neurosurgical patients (mean age, 54.9 years; 90 [57%] were women) from 1995 through 1998, to determine the incidence of, risk factors for, and organisms that cause ventriculitis. A total of 196 IVC events resulted in 11 infections (5.6%; 9 were caused by gram-negative organisms and 2 by coagulase-negative staphylococci). Independent risk factors for IVC-related infection include length of IVC placement (8.5 days [infected] vs. 5.1 days [uninfected]; P=.007) and cerebrospinal fluid leakage about the IVC (P=.003). The length of hospital stay (30.8 days vs. 22.6 days; P=.03) and mean total hospital charges ($85,674.27 vs. $55,339.21; P=.009) were greater for infected patients than for uninfected patients. In addition, a microbiologic shift from gram-positive organisms toward gram-negative organisms was noted. This study suggests that IVC-related infections remain serious infections that increase the length of hospitalization.

Adult↗
PubMed2001

Patients' health-related quality of life and utilities associated with different stages of amyotrophic lateral sclerosis.

OBJECTIVES: Amyotrophic lateral sclerosis (ALS) is a devastating disease that has serious consequences in terms of impairments and disabilities, which are expected to impact on health-related quality of life (HRQL). The aim of the present study was to assess self-reported health status and HRQL, as well as patients' own valuation of their present health state in a sample of patients with different levels of severity of ALS. METHODS: Structured interviews were conducted with 77 patients with different levels of disease severity. Patients completed a disease-specific health status measure (ALSAQ-40), a generic health status measure (EuroQol EQ-5D), visual analogue scale (VAS) rating of current health and a standard gamble (SG) exercise to provide health state utilities for their own health state. RESULTS: The results from the ALSAQ-40 and EQ-5D descriptive system indicate that patients' HRQL decreases systematically with increasing severity of disease. Patients' mean VAS rating of their own health ranged from 0.74 for stage 1 (early) disease severity, to 0.37 for stage 4 (late stage) disease severity. Utilities elicited via SG were systematically higher than VAS scores and ranged from a mean of 0.79 for stage 1 disease severity to a mean of 0.45 for stage 4 disease severity.

Activities of Daily Living↗
PubMed2001

Postmortem whole-body magnetic resonance imaging as an adjunct to autopsy: preliminary clinical experience.

The purpose of this study was to evaluate whole-body magnetic resonance imaging (MRI) of cadavers as an adjunct to autopsy. Eight consecutive patients underwent both whole-body MRI and autopsy [either conventional (six), limited (one), or percutaneous (one)] within 24 hours of death. Comparison was made of major and minor abnormalities and predicted cause of death recorded by independent readers at both MRI and autopsy. Major discrepancies between the recorded primary cause of death at imaging and autopsy occurred in five (5) patients. These included a myocardial infarction found at autopsy alone, bowel infarction and portal venous gas found at MRI alone, and aortic dissection and occipital infarct found at MRI alone in a patient on whom only limited autopsy was performed. Postmortem MRI may represent a useful adjunct to autopsy, particularly in patients in whom autopsy is limited due to patient/family consent, inoculation risks, and ethnic doctrines.

Aged↗
PubMed2001

Altered HLA-G transcription in pre-eclampsia is associated with allele specific inheritance: possible role of the HLA-G gene in susceptibility to the disease.

Pre-eclampsia is a disorder of human pregnancy occurring in 5-10% of all births, and represents the leading cause of infant morbidity and mortality and maternal death. In pre-eclampsia, invasion of fetal trophoblasts into maternal arteries during early pregnancy is shallow or absent. Here we examined the hypothesis that HLA-G, a non-classical class I HLA expressed in cytotrophoblasts, may act as a key gene in pre-eclampsia. We analysed HLA-G at the level of transcription and genotyped a silent CAC-CAT polymorphism in exon 3 and a 14-bp insertion/deletion in the 3' untranslated region. A deficit in levels of the HLA-G3 transcript was observed in mild pre-eclampsia compared to normal placentas. The distribution of HLA-G polymorphisms was different between normal and pre-eclampsia samples. A correlation between the alteration in transcription of the HLA-G gene and certain HLA-G genotypes was also observed. Thus we provide the first evidence for a possible role of HLA-G in genetic susceptibility to, and pathogenesis of pre-eclampsia.

Alleles↗
PubMed2001

The effect of lithium chloride on the biooxidation of aqueous methanol/acetone mixtures.

Lithium chloride, more specifically the lithium cation, has been implicated in interference in biological systems. In the case of Escherichia coli, interference involves the Na+(Li+)/H+ antiporter transport system. The study reported here concerns the effects of LiCl on a mixed enrichment culture that is able to biodegrade both methanol and acetone under aerobic conditions. The results obtained using unsteady state continuous flow culture techniques demonstrate a significant disruptive effect of LiCl on culture performance. In addition, a reduction in the substrate-based biomass yield coefficient, which is a clear advantage as far as biotreatment process performance is concerned, also occurs. The ultimate fate of the LiCl was not determined.

Acetone↗