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Biomedical subjects

V Williams

Publications and source records attributed to V Williams.

At least 19 recordsLinked to original sources
PubMed2006

Test case based risk predictions using artificial neural network.

INTRODUCTION: The traditional fuzzy-rule-based risk assessment technique has been applied in many industries due to the capability of combining different parameters to obtain an overall risk. However, a drawback occurs as the technique is applied in circumstances where there are multiple parameters to be evaluated that are described by multiple linguistic terms. METHOD: In this study, a risk prediction model incorporating fuzzy set theory and Artificial Neural Network (ANN) capable of resolving the problem encountered is proposed. An algorithm capable of converting the risk-related parameters and the overall risk level from the fuzzy property to the crisp-valued attribute is also developed. Its application is demonstrated by a test case evaluating the navigational safety within port areas. RESULTS: It is concluded that a risk predicting ANN model is capable of generating reliable results as long as the training data takes into account any potential circumstance that may be met. IMPACT ON INDUSTRY: This paper provides safety assessment practitioners with a novel and flexible framework of modelling risks using a fuzzy-rule-base technique. It is especially applicable in circumstances where there are multiple parameters to be considered. The proposed framework also enables the port industry to manage navigational safety in a rational manner.

Algorithms↗
PubMed2006

Survey of the prevalence, diagnosis and treatment of dermatological conditions in small animals in general practice.

A survey was made of the prevalence, diagnosis and treatment of dermatological conditions in small animals in general practice in the UK. Out of 3707 small animal consultations in general practice that were observed and recorded, 795 (21.4 per cent) involved animals that had a dermatological problem. In dogs and exotic species, pruritus was the most common presenting sign, accounting for 30 to 40 per cent of the dermatological consultations. In cats, cutaneous swellings were the most common presentation (36 per cent). A diagnosis or recommendation for treatment was made on the basis of the presenting clinical signs and physical examination alone in 576 (72 per cent) of the cases, and various diagnostic tests were performed in the other cases. In dogs, parasitic infestations, bacterial infections and neoplasia accounted for the majority of the diagnoses. In cats, parasites and bacterial infections were the most common. In exotic species, parasites accounted for over 80 per cent of the dermatological diagnoses. In dogs, the most common final diagnoses were otitis, pyoderma, anal sac impaction, flea infestation and atopic dermatitis. In cats, abscesses, flea infestation, and otitis were the most common diagnoses. In exotic species, the most common diagnosis was an unspecified mite infestation. Systemic antibiotics were prescribed in 196 cases (25 per cent), systemic glucocorticoids were prescribed in 162 cases (20 per cent) and treatment with an ectoparasiticide was prescribed in 167 cases (21 per cent).

Animals↗
PubMed2006

Proteomic analyses of male contributions to honey bee sperm storage and mating.

Honey bee (Apis mellifera L.) queens mate early in life and store sperm for years. Male bees likely contribute significantly to sperm survival. Proteins were extracted from seminal vesicles and semen of mature drones, separated by electrophoresis, and analysed by peptide mass fingerprinting. Computer searches against three databases, general species, honey bees and fruit flies, were performed. Spectra were used to query the recently generated honey bee genome protein list as well as general species and fruit fly databases. Of the 69 unique honey bee proteins found, 66 are also in Drosophila melanogaster. Two proteins only matched honey bee genes and one is a widespread protein lost from the fly genome. There is over-representation of genes implicated in the glycolysis pathway. Metabolism-associated proteins were found primarily in the seminal vesicle. Male accessory gland proteins as identified in Drosophila rarely had orthologs among proteins found in the honey bee. A complete listing of gel spots chosen including honey bee genome matches and Mascot searches of MALDI-TOF results with statistics is in the Supplementary table. MALDI-TOF spectra and more complete Mascot peptide mass fingerprinting data are available on request. Supplementary figs 1-3 show the stained protein gels.

Animals↗
PubMed2006

CpG-C ISS-ODN activation of blood-derived B cells from healthy and chronic immunodeficiency virus-infected macaques.

Cytosine-phosphate-guanine class C (CpG-C) immunostimulatory sequence oligodeoxynucleotides (ISS-ODNs) activate human B cells and dendritic cells (DCs), properties that suggest potential use as a novel adjuvant to enhance vaccine efficacy. After demonstrating that the CpG-C ISS-ODN C274 activates macaque DCs, we examined in vitro activation of macaque B cells by C274 as a prelude to evaluation of this molecule as an adjuvant in the testing of candidate human immunodeficiency virus vaccines in the rhesus macaque-simian immunodeficiency virus (SIV) model. C274 induced macaque CD20(+) B cells to proliferate more strongly than CD40 ligand or CpG-B ISS-ODN. C274 enhanced B cell survival; increased viability was most evident after 3-7 days of culture. Increased expression of CD40, CD80, and CD86 by B cells was apparent within 24 h of exposure to C274 and persisted for up to 1 week. C274-stimulated, B cell-enriched and peripheral blood mononuclear cell suspensions from naïve and immunodeficiency virus-infected monkeys secreted several cytokines [e.g., interleukin (IL)-3, IL-6, IL-12, interferon-alpha] and chemokines [e.g., monocyte chemoattractant protein-1/CC chemokine ligand 2 (CCL2), macrophage-inflammatory protein-1alpha/CCL3, IL-8/CXC chemokine ligand 8]. In comparison, exposure of macaque B cells to SIV had minimal impact on surface phenotype, despite inducing cytokine and chemokine production in cells from infected and uninfected animals. These observations emphasize the need to identify strategies to optimally boost immune function, as immunodeficiency viruses themselves only partially activate B cells and DCs. The ability of C274 to stimulate B cells and DCs in healthy and infected monkeys suggests its possible use as a broad-acting adjuvant to be applied in the rhesus macaque model for the development of preventative and therapeutic vaccines.

AIDS Vaccines↗
PubMed2004

Sperm storage and antioxidative enzyme expression in the honey bee, Apis mellifera.

Honey bee (Apis mellifera) sperm remains viable in the spermatheca of mated female honey bees for several years. During this time, the sperm retains respiratory activity, placing it at risk of the damaging effects of reactive oxygen species common to many biological processes. Antioxidative enzymes might help reduce this damage. Here we use quantitative real-time RT-PCR to establish gene-expression profiles in male and female honey bee reproductive tissues for three antioxidative enzymes: catalase, glutathione-S-transferase (GST) and superoxide dismutase (SOD1, cytosolic). Catalase and GST showed ten- to twenty-fold transcript increases in the sperm storage organs of mated queens vs. unmated queens, whereas SOD1 levels are high in both mated and unmated queens. Male reproductive and somatic tissues showed relatively high levels of all three antioxidant-encoding transcripts. All three enzymes screened were higher in mature males vs. young males, although this effect did not appear to be confined to reproductive tissues and, hence, need not reflect a role in sperm longevity. Furthermore, antioxidative enzyme transcripts remained present, and apparently increased, in male tissues long after sperm had matured and seminal fluid was produced. We also found measurable levels of catalase transcripts in honey bee semen. The presence of catalase transcripts in both reproductive tissues and semen in bees suggests that this enzyme might play a key role in antioxidative protection.

Age Factors↗
PubMed2001

Preliminary characteristics of the prothrombin converting enzyme from venom of Stephen's banded snake (Hoplocephalus stephensii).

Stephen's banded snake (Hoplocephalus stephensii) is an infrequently encountered Australian elapid species. The crude venom contains coagulant activity and the component responsible is a prothrombin activator requiring factor V for activity. SDS-PAGE of the isolated native protein revealed two bands at 23 and 36 kDa. These findings indicate that the procoagulant is similar to that found in the Australian tiger snake (Notechis scutatus) and thus resembles factor Xa.

Animals↗
PubMed2001

Reliability and validity of a modified Colorado Symptom Index in a national homeless sample.

This study examined the reliability and construct validity of a modified version of the Colorado Symptom Index (MCSI), a brief, self-report measure of psychological symptomatology, in a study of interventions to prevent homelessness. Eight projects in a national, cooperative study collected new data at baseline, 6, and 12 months using a set of common measures as well as site-specific instruments. The pooled sample consisted of 1,381 persons in treatment for mental illness or substance abuse (or both), of which 84% had a history of homelessness. The analyses employed classical and Rasch methods to examine the MCSI's content validity, internal consistency and item quality, test/retest reliability, dimensionality, appropriateness for the sample, construct validity, and responsiveness to change. This 14-item scale was found to be a reliable and valid measure of psychological symptoms in this sample. Its content was consistent with other symptom measures, its high internal consistency and test-retest coefficients supported its reliability, its relationships to other measures indicated that it had good construct validity, and it was responsive to change. We conclude that the MC

Adolescent↗
PubMed2000

Central venous catheter placement in patients with disorders of hemostasis.

BACKGROUND: Patients requiring central venous access frequently have disorders of hemostasis. The aim of this study was to identify factors predictive of bleeding complications after central venous catheterization in this group of patients. METHODS: A retrospective analysis of all central venous catheters placed over a 2-year period (1997 to 1999) at our institution were performed. The age, sex, clinical diagnosis, most recent platelet count, prothrombin international normalized ratio (INR), activated partial thromboplastin time (aPTT), catheter type, the number of passes to complete the procedure, and bleeding complications were retrieved from the medical records. RESULTS: In a 2-year period, 2,010 central venous catheters were placed in 1,825 patients. Three hundred and thirty placements were in patients with disorders of hemostasis. In 88 of the 330 patients, the underlying coagulopathy was not corrected before catheter placement. In these patients, there were 3 bleeding complications requiring placement of a purse string suture at the catheter entry site. In the remaining 242 patients, there was 1 bleeding complication. Of the variables analyzed, only a low platelet count (<50 x 10(9)/L) was significantly associated with bleeding complications. CONCLUSION: Central venous access procedures can be safely performed in patients with underlying disorders of hemostasis. Even patients with low platelet counts have infrequent (3 of 88) bleeding complications, and these problems are easily managed.

Blood Coagulation Disorders↗
PubMed1999

Pregnancy and perinatal outcomes in migraineurs using sumatriptan: a prospective study.

BACKGROUND: Sumatriptan is an acute treatment for migraine which is often used by women in their child-bearing years, and who become unexpectedly pregnant. Within the context of the post-marketing use of sumatriptan injection for the acute treatment of migraine, and in compliance with approved labeling, we wished to compare perinatal pregnancy outcomes in women who did and did not use the drug after conception. METHODS: Open-label, prospective study conducted in 12,339 migraineurs (including 9,861 women) whose demography and consumption pattern of sumatriptan injections were typical, and were predicted to include 150 pregnancies. Outcome of pregnancy was the end-point. RESULTS: There were 168 of 173 pregnancies that were well-documented. Sumatriptan was only used prior to conception in 92 cases. There were 76 first trimester exposures to sumatriptan. There were no differences in pregnancy outcome between the two groups. CONCLUSIONS: Perinatal and pregnancy outcome did not differ between patients who had and had not used sumatriptan after conception, at the resolution of these sample sizes. This study design complements the ongoing pregnancy registry, which is now widened to patients exposed to all formulations of sumatriptan.

Abortion, Spontaneous↗
PubMed1999

Investigation of female survival benefit in metastatic melanoma.

Epidemiological studies show female survival benefit in advanced metastatic melanoma. In investigating a possible mechanism for this female survival benefit, we have previously reported that the female steroid 17beta-oestradiol significantly reduces invasion of a human melanoma cell line (A375-SM cells) and ocular melanoma cells through fibronectin. Neither cell type was found to possess oestrogen receptor-alpha. The aim of the current study was to obtain further information on the extent to which progression of cutaneous melanoma might be sex steroid sensitive by (a) examining the relationship between circulating sex steroids, sex hormone binding globulin and disease progression; (b) examining the relationship between sex steroid structure and the ability of steroids to reduce invasion of a melanoma cell line in vitro; and (c) examining the effects of sex steroids on proliferation of these cells in vitro. We report a significant reduction in circulating oestrone with disease progression in male but not female patients. Examining steroids for their ability to inhibit invasion of A375-SM cells through fibronectin in vitro, oestrogenic compounds (17beta-oestradiol and oestrone) were found to inhibit invasion; in this respect, oestrone was approximately 50 times more potent than 17beta-oestradiol; steroids lacking the benzene ring structure did not inhibit invasion, indeed dehydroepiandrosterone (DHEA) which acts as a precursor to androgenic steroids significantly enhanced invasion. Proliferation of A375-SM cells was unaffected by 17beta-oestradiol, oestrone or dihydrotestosterone when cells were cultured on plastic; in contrast, all three steroids induced modest proliferation of cells when grown on fibronectin with dihydrotestosterone the most mitogenic of the three steroids. These data are consistent with sex steroids playing a role in melanoma progression.

Adolescent↗
PubMed1999

AHCPR-funded rural managed care centers: report from the field.

In 1994, the Agency for Health Care Policy and Research awarded cooperative agreements to five University-based groups to promote the establishment of managed care institutions and development of rural health networks. This paper summarizes the experiences of these rural managed care centers in the first three years of this initiative. Key ingredients for achieving the project's goals that are identified by the project directors are reported as "foundations" that must be in place from the outset, or "building blocks" that can be developed along the way. The development of information systems and efforts to foster leadership in the medical community are areas in which grant funding of this type can be most effective.

Community Networks↗
PubMed1999

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Adult↗
PubMed1998

Rural attachments for students in the health professions: are they worthwhile?

In the period 1991-96, 156 undergraduates from 14 health disciplines at the University of Sydney completed rural attachments in rural and remote areas of Australia as part of the Rural Careers Project. On return from their attachment, students were encouraged to write a brief report of their experiences. Ninety-two available reports were analysed as one means of assessing the success of the attachments with respect to informing students about rural health issues and stimulating their interest in rural careers after graduation. A content analysis of the students' written comments about their perceptions and experiences was completed. Students were extremely positive about the value of the attachments and expressed more positive than negative comments regarding their perceptions of rural life and work. The results show that rural attachments are indeed worthwhile learning opportunities.

Allied Health Personnel↗
PubMed1997

Abbreviated educational session improves cranial computed tomography scan interpretations by emergency physicians.

STUDY OBJECTIVE: Previously published research (phase I) demonstrated a concerning misinterpretation rate of cranial computed tomography (CT) scans by emergency physicians. This study (phase II) determined whether an abbreviated educational session would improve emergency physician interpretation skills of cranial CT scans. METHODS: Participants in this prospective, interventional study in a county hospital ED were patients undergoing cranial CT scanning during ED evaluations and attending level emergency physicians. An abbreviated educational session on cranial CT interpretation skills was given to the same attending emergency physicians who participated in phase I. The educational session included basic CT interpretation skills and misinterpreted CT scans from phase I. We determined the postsession accuracy rate of the emergency physicians on 324 ED patient CT scans. The CT interpretation accuracy rates were then compared between phase I and phase II to determine the effectiveness of the educational session. RESULTS: The radiology/ED CT scan concordance rate improved from 61.3% (kappa = .22) to 88.6% (kappa = .70; P < .0001). Potentially clinically significant CT scan misinterpretations decreased from 24.1% to 4.0% (P < .0001). Most importantly, major missed findings on CT scans decreased from 11.4% to 2.8% (P < .0001). Continuous quality improvement monitoring found no instance of clinically significant patient mismanagement. CONCLUSION: Within the limits of this study, we conclude that emergency physicians' interpretation skills of cranial CT scans may be improved using a 1-hour educational session.

Brain Diseases↗