PubMed Health⌕ Search

Biomedical subjects

S Williams

Publications and source records attributed to S Williams.

At least 19 recordsLinked to original sources
PubMed2006

Development and validation of a real-time Taqman PCR assay for the detection and quantitation of infectious laryngotracheitis virus in poultry.

In this study, the development and validation of a real-time (ReTi) PCR assay is described using a Taqman labeled probe for the detection and quantitation of infectious larygotracheitis virus (ILTV) in chickens. The ReTi ILTV assay was highly specific with a quantitation limit of 100 viral template copies per amplification reaction. In experimentally infected, birds during early acute stages of infection, an average of 6.67 log(10) viral template copies/amplification reaction were detected, while at chronic late stages of infection an average of 2.86-3.27 log(10) viral template copies/amplification reaction were detected. A total of 246 tracheal swab samples collected from natural outbreaks of the disease were tested by virus isolation and the ReTi ILTV assay. Both assays agreed in 37% of the samples tested and the ReTi ILTV assay detected approximately 3.7 times more positives samples than virus isolation. A minimum of 5 log(10) viral template copies/amplification reaction were required from a tracheal swab to render a virus isolation positive result. In conclusion, the ReTi ILTV assay was highly specific, sensitive, reproducible, and capable of reliably quantifying viral nucleic acid directly from clinical samples.

Animals↗
PubMed2006

Isolation and characterization of UHMWPE wear particles down to ten nanometers in size from in vitro hip and knee joint simulators.

There is currently considerable interest in the wear debris and osteolytic potential of different types of bearings used in total joint replacements. The biological activity of the wear debris is dependent on the size and volume of the particles produced. Wear volume also plays an important role in the functional biological activity of a joint replacement. In vitro studies have shown that crosslinking of ultra high molecular weight polyethylene (UHMWPE) acetabular cups and tibial trays produces a reduction in wear volume, and crosslinking has now been introduced clinically for both types of prostheses. Previous studies have identified both micron and submicron-sized polyethylene wear particles. The aim of this study was to characterize the wear and wear particles generated from moderately crosslinked GUR 1,020 GVF UHMWPE acetabular cups and tibial trays in hip and knee joint wear simulators down to 10 nanometers in size. The wear rates of the two prosthesis types were very similar at 25.6 +/- 5.3 mm(3) per million cycles for the hip prostheses and 22.75 +/- 5.95 mm(3) per million cycles for the knee prostheses. Nanometer-sized wear particles were isolated and characterized from both hip and knee simulator lubricants for the first time. Significantly higher numbers (p < 0.05) of particles in the nanometer (<0.1 microm) size range were produced by the hip prostheses compared to the knee prostheses. The knee prostheses produced larger particles, with the mode of particle size in the 0.1-1.0 microm size range, compared to <0.1 microm size range for the hip prostheses. In addition, the knee prostheses produced a greater volumetric concentration of wear particles in the 1.0-10 microm size range, and consequently lower specific biological activity and functional biological activity indices. These results indicated that the knee prostheses had a lower osteolytic potential compared to the hip prostheses.

Biocompatible Materials↗
PubMed2006

Histopathological reporting of paediatric cutaneous vascular anomalies in relation to proposed multidisciplinary classification system.

BACKGROUND: The terminology applied to vascular anomalies has been variable in previously published literature making interpretation suboptimal. The International Society for the Study of Vascular Anomalies (ISSVA) has proposed a revised classification based on clinical features and histopathological findings. This classification is increasingly being accepted as clinically useful and a platform for future studies. AIMS: To examine the extent to which the ISSVA classification can be practically applied to diagnostic histopathological specimens. METHODS: Cutaneous vascular lesions received in a single paediatric pathology unit during a 2-year period (2004-5) were reviewed, including glucose transporter protein 1 (GLUT1) immunostaining where required, and lesions were reclassified according to the ISSVA classification. RESULTS: 144 specimens were identified. Appropriate full clinical information was provided in only 17% of cases at submission. Infantile haemangiomas comprised 46% of cases, 18% of which were regressive type, initially inaccurately identified as vascular malformations before GLUT1 immunostaining. 30% of lymphatic malformations and all lymphovenous malformations were previously classified as vascular malformations, not otherwise specified. CONCLUSIONS: The ISSVA classification of vascular anomalies provides a useful framework for histopathologists to classify vascular anomalies. However, meaningful and appropriate use of such a system is dependent on the adequacy of clinical information provided and routine use of immunohistochemical markers.

Biomarkers, Tumor↗
PubMed2006

Building an anonymized catalogued radiology museum in PACS: a feasibility study.

The aim of this study was to test the feasibility of a software application that would allow the anonymization and cataloguing of whole DICOM datasets in order to build searchable radiology museums within PACS. The application was developed on a dedicated networked PC, using C# and HL7 coding. Whole DICOM datasets were pushed from PACS to a networked PC on which the application, Museum Builder, was developed. Museum Builder works by replacing the patient specific data (the forename, surname and hospital number) within each header of each DICOM file with terms from anatomical and surgical sieve menus. The date of birth is anonymized to 1 January of the same year. Whole DICOM datasets comprising hundreds of images can be anonymized and catalogued in a single episode. Museum Builder primes PACS with an HL7 script to receive a "new" patient. DICOM datasets are then pushed back to PACS where they are added to the database as "new" cases. The museum cases can then be searched for, on PACS, by any combination of terms that correspond to appropriate anatomical units, surgical sieve headings or radiological specialty. New radiology reports containing clinical histories, radiological descriptions, differential diagnoses and discussion can be added through the report window. Our institution has developed and used this tool to generate a PACS based radiology museum containing not only full DICOM datasets, but also relevant histological and clinical photographs. In conclusion, this technique offers a mechanism for generating anonymized catalogued radiology museums in PACS. Museum Builder represents a working prototype that demonstrates some of the archiving functions that are expected by teaching institutions from PACS.

Cataloging↗
PubMed2006

Matrix metalloproteinase-13 influences ERK signalling in articular rabbit chondrocytes.

OBJECTIVE: Matrix metalloproteinase-13 (MMP-13) is an extracellular MMP that cleaves type II collagen, the major protein component of cartilage, with high specificity and has been implicated in the pathology of osteoarthritis. The present study aimed to characterize the binding and internalization kinetics of MMP-13 in normal rabbit chondrocytes and whether MMP-13 affected cell signalling. METHODS: Rabbit chondrocytes were used in [125I]-MMP-13 binding assays to investigate the MMP-13 binding kinetics and Western analysis allowed for the assessment of intracellular signalling cascades. RESULTS: Rabbit chondrocytes were found to express the cartilage-specific genes aggrecan and type II collagen throughout their in vitro culture period. Appreciable specific cell-association of [125I]-MMP-13 was detected after 10 min of exposure to the ligand and equilibrium was obtained after 2 h. Binding of [125I]-MMP-13 to chondrocytes was specific and approached saturation at 75 nM. Internalization of MMP-13 was evident after 20 min, reached a maximum at 30 min and had returned to baseline by 90 min. Addition of receptor-associated protein (RAP) inhibited the internalization of MMP-13 indicating a likely role for low-density lipoprotein receptor-related protein-1 (LRP1) in this process. Interestingly the presence of MMP-13 induced phosphorylation of the extracellular signal-regulated kinase 1/2 (ERK1/2) protein showing that there is initiation of a signalling process in response to MMP-13 being bound and internalized by rabbit chondrocytes. However, this activation does not involve the MMP-13 internalization receptor LRP1. CONCLUSION: These studies demonstrate and characterize the MMP-13 binding and internalization system in rabbit chondrocytes and indicate that MMP-13 may regulate the phenotype of the chondrocytes through this receptor system.

Aggrecans↗
PubMed2006

The effectiveness of treatment for depression/depressive symptoms in adults with cancer: a systematic review.

Depression is common in cancer patients, and this often remains undetected and untreated. Depression has been associated with poorer quality of life, in addition to increased impairment of immune response and poorer survival in cancer patients. Previous systematic reviews and meta-analyses of the efficacy of interventions for cancer patients with depression have failed to distinguish between caseness for depression and depressive symptoms. The findings from this systematic review show that there is limited trial data on the efficacy of prescribed antidepressants in reducing the incidence of major depression and depressive symptoms in cancer patients. Contrary to previous reviews that failed to distinguish between depressive symptoms and depression, this review found very little data from clinical trials (without the possibility of confounding factors) to demonstrate that psychotherapeutic interventions are effective in reducing depression in cancer patients. A number of small-scale, single-centre trials indicated that psychotherapeutic interventions (especially cognitive behavioural therapy) can have effects on depressive symptoms in cancer patients. However, given the methodological limitations of studies to date, lack of evidence should not be interpreted as implying lack of efficacy. In conclusion, there is a need for adequately powered studies of pharmacological and psychotherapeutic studies, which are targeted at cancer patients with a diagnosis of depression and include monitoring of the use of other pharmacological/psychotherapeutic and complementary and alternative medicine interventions.

Antidepressive Agents↗
PubMed2006

[Effect of urea nail lacquer on nail quality. Clinical evaluation and biophysical measurements].

BACKGROUND: Urea is a well-known humectant. The aim of our study was to evaluate the in vivo effect of 10% urea lacquer on nail quality. METHODS: 60 healthy probands with brittle nails were included in a randomized, controlled study. The nail lacquer was applied once (n=30) or twice daily (n=30) on one hand for 28 days, while the other hand served as untreated control. Assessments included clinical evaluations and bioengineering measurements. RESULTS: Application of the nail lacquer was well-tolerated and led to a significant clinical improvement of nail surface morphology, nail plate consistency, reflection of the nail plate surface, appearance of the cuticle and the nail fold. Sonographic nail density was slightly increased. No relevant changes were found in nail thickness and transonychial water loss. CONCLUSIONS: Nail lacquer containing urea improves the cosmetic appearance of fingernails.

Adult↗
PubMed2006

Evaluation of multiple immune parameters after vaccination with modified live or killed bovine viral diarrhea virus vaccines.

The development of immunity to vaccine antigen was examined using three prime/boost strategies and the progression of immune activities was evaluated over the course of 8 weeks. Calves were vaccinated and multiple immune parameters were evaluated using several methods to assess humoral or cellular immunity from the same samples in parallel. The three vaccination protocols used were a killed vaccine followed by a killed boost (killed/killed), MLV vaccine and boost (MLV/MLV), or a MLV vaccine and killed boost (MLV/killed). All the vaccines used included modified live IBR/PI3 viruses to make the bystander context as similar as possible. The Singer strain of BVDV was used as the source antigen in the killed vaccine, and the NADL strain of BVDV was used in the MLV vaccine. Controls received a vaccine containing only MLV IBR/PI3. The assessment panel measured SN titers, as well as lymphocyte proliferation, cytokine mRNA expression, intracellular cytokine production, and released IFN-gamma after in vitro stimulation with three strains of BVDV virus. MLV/MLV and MLV/killed groups developed significant SN titers to the type 1 BVDV virus strains, Singer and NADL, and low crossover titers were also seen to the type 2 strain, 890 over the evaluation period. These two groups showed significant proliferation in response to the NADL virus as compared to controls. Multiple immune assessments were conducted simultaneously to attempt to provide a broader, more in depth evaluation of immune response to these BVDV vaccination protocols. We observed that the correlation among most of the assays conducted were weak; the correlation between SN titers and cellular proliferation assays demonstrated a moderate correlation.

Animals↗
PubMed2006

Condom use with steady and casual partners in inner city African-American communities.

OBJECTIVES: This study examined rates of and factors associated with consistent condom use with steady partner and with casual partners in inner city African-American communities with high sexually transmitted infection (STI) prevalence. METHODS: Structured interviews were conducted using street intercept methods and venue based sampling with 997 African-American residents of inner city neighbourhoods in Houston and Dallas, Texas; of which data were analysed for the 736 that reported having sex in past 2 months. Condom use was measured as a proportion of use in last five sex acts with steady and casual partners. RESULTS: Reported rates of consistent condom use were high-31.4% with steady partner and 29.5% with casual partner. Multivariate logistic models differed by type of partner. Married people and those with history of STI were less likely to use condoms with the main partner, while older people were less likely and males, and those visiting a doctor more likely to use condoms with casual partners. CONCLUSIONS: The proportion of condom use with both partner types was relatively high reflecting a general trend towards increased condom use in the United States. The finding of lower reported rates with casual partners has been discussed. Factors associated with condom use differ according to type of partner. Precise measurement of actual condom use continues to be an elusive task but is required for the design of appropriate messages and evaluation of STI programmes.

Adult↗
PubMed2006

Metal-on-metal bearings surfaces: materials, manufacture, design, optimization, and alternatives.

When first introduced, total hip replacements offered pain relief and improved mobility in elderly patients. The success of this procedure in terms of long-term durability and restoration of function has led to its use in younger, more active patients. This has resulted in a commensurate increase in patient expectation regarding longevity and the degree to which function and lifestyle is restored. The bearing surface is a key feature of the performance of replacement joints. It is generally accepted that excessive amounts of wear debris preclude their long-term survivorship and hence there is an ongoing requirement for bearing surfaces which minimize debris generation. The purpose of this paper is to review the factors which affect the performance of so-called metal-on-metal bearings, to compare their performance with that of the other commonly used contemporary alternatives, metal and ceramic articulating against highly cross-linked polyethylene, and ceramic-on-ceramic, and finally to consider the potential solutions offered by new developments such as ceramic-on-metal and coatings applied to metal-on-metal bearings.

Arthroplasty, Replacement, Hip↗
PubMed2005

A functional glutamatergic neurone network in the medial septum and diagonal band area.

The medial septum and diagonal band complex (MS/DB) is important for learning and memory and is known to contain cholinergic and GABAergic neurones. Glutamatergic neurones have also been recently described in this area but their function remains unknown. Here we show that local glutamatergic neurones can be activated using 4-aminopyridine (4-AP) and the GABA(A) receptor antagonist bicuculline in regular MS/DB slices, or mini-MS/DB slices. The spontaneous glutamatergic responses were mediated by AMPA receptors and, to a lesser extend, NMDA receptors, and were characterized by large, sometimes repetitive activity that elicited bursts of action potentials postsynaptically. Similar repetitive AMPA receptor-mediated bursts were generated by glutamatergic neurone activation within the MS/DB in disinhibited organotypic MS/DB slices, suggesting that the glutamatergic responses did not originate from extrinsic glutamatergic synapses. It is interesting that glutamatergic neurones were part of a synchronously active network as large repetitive AMPA receptor-mediated bursts were generated concomitantly with extracellular field potentials in intact half-septum preparations in vitro. Glutamatergic neurones appeared important to MS/DB activation as strong glutamatergic responses were present in electrophysiologically identified putative cholinergic, GABAergic and glutamatergic neurones. In agreement with this, we found immunohistochemical evidence that vesicular glutamate-2 (VGLUT2)-positive puncta were in proximity to choline acetyltransferase (ChAT)-, glutamic acid decarboxylase 67 (GAD67)- and VGLUT2-positive neurones. Finally, MS/DB glutamatergic neurones could be activated under more physiological conditions as a cholinergic agonist was found to elicit rhythmic AMPA receptor-mediated EPSPs at a theta relevant frequency of 6-10 Hz. We propose that glutamatergic neurones within the MS/DB can excite cholinergic and GABAergic neurones, and that they are part of a connected excitatory network, which upon appropriate activation, may contribute to rhythm generation.

Action Potentials↗
PubMed2005

Neuronal effects of acute citalopram detected by pharmacoMRI.

RATIONALE: Serotonin (5-hydroxytryptamine, 5-HT) is implicated in the aetiology and treatment of a variety of psychiatric disorders. A limitation of research has been the necessity to use indirect measures of 5-HT function. METHOD: We describe a method of analysing pharmacoMRI data using SPM and apply it to the direct i.v. infusion of selective 5-HT reuptake inhibitor, citalopram, in 12 healthy volunteers. Scanning took place on a 1.5-T Philips MRI scanner. RESULTS: Areas implicated in depression and its treatment were observed to have increasing signal with respect to time. These areas included the caudate, the amygdala, the hippocampus, the striatum and the thalamus. CONCLUSION: Direct pMRI using i.v. citalopram opens new ways of investigating 5-HT mechanism in depression and its treatment.

Adult↗
PubMed2005

In search of candidate genes critically expressed in the human endometrium during the window of implantation.

BACKGROUND: In this prospective randomized blinded clinical trial, we examined gene expression profiles of the human endometrium during the early and mid-luteal phases of the natural cycle. METHODS: An endometrial biopsy was performed on day 16 (LH +3) or on day 21 (LH +8), followed by RNA extraction and microarray analysis using an Affymetrix HG-U95A microchip. Data analysis was carried out using pairwise multiple group comparison with the significance analysis of microarrays (SAM) software. RESULTS: With a false discovery rate of 0, the analysis revealed that 107 genes were significantly and differently expressed (> or =2-fold) during the early versus the mid-luteal phase of the cycle. Forty-five of these genes have not been previously linked to endometrial receptivity. Validation of the microarray data was accomplished using semiquantitative RT-PCR. We demonstrated the presence of estrogen and progesterone response elements (ERE and PRE) by analysis of the 5'-flanking regions of a subset of differentially regulated genes. CONCLUSIONS: Using a strict bioinformatics approach of microarray data, we demonstrated significant changes in candidate genes during the transition of the early to the mid-luteal phase of the human endometrium that may have functional significance for the opening and maintenance of the window of implantation.

Adult↗
PubMed2005

Cholesterol lowering effects of nuts compared with a Canola oil enriched cereal of similar fat composition.

BACKGROUND AND AIM: Small quantities of nuts protect against subsequent cardiovascular risk. There is speculation that the cholesterol lowering effect associated with nut consumption arises primarily from the fatty acid composition of nuts but may be caused by some other component. To evaluate this possibility we compared the effect of various nuts, against a Canola oil based cereal with a comparable fatty acid profile, on lipids, lipoproteins and fatty acids to determine whether the fatty acid profile of nuts explains their cholesterol lowering effects. METHODS AND RESULTS: Twenty-eight men and women with mean (s.d.) levels of total and low density lipoprotein cholesterol of 6.0 (1.1) mmol/L, and 4.1 (1.0) mmol/L, respectively and a mean body mass index (BMI) of 26.9 (3.2) kg/m2 took part in a randomised cross over trial. For two periods of six weeks, separated by a four-week washout, participants were asked to consume a low saturated fat diet, which included either 30 g/d nuts (nut diet) or one serving of a cereal containing Canola oil (cereal diet). There were no significant differences in the lipids, lipoproteins, plasma fatty acids or other variables between the two diets at the end of the study. Total cholesterol (TC) and low density lipoprotein cholesterol (LDL-C) were lower on both experimental diets than at baseline, 0.51 mmol/L and 0.40 mmol/L (p<0.001, p<0.01), respectively on the nut diet and 0.42 mmol/L and 0.37 mmol/L (p<0.001, p<0.01), respectively on the cereal diet. CONCLUSION: A 30 g serving of nuts, or a serving of a Canola oil enriched cereal with a similar fatty acid composition reduced total and LDL cholesterol to a similar extent when consumed as part of a lipid lowering diet. Results suggest that foods with a similar fatty acid composition to nuts can produce comparable decreases in lipoprotein mediated cardiovascular risk.

Cholesterol↗
PubMed2005

Use of recombinant factor VIIa in pediatric patients with liver failure and severe coagulopathy.

BACKGROUND: Several reports have suggested a benefit for recombinant Factor VIIa (rFVIIa) in nonhematological conditions, including liver disease and transplantation. However, there are few reports of its use in children with liver failure. Recently, we used rFVIIa in four patients with liver failure and severe coagulopathy with bleeding who demonstrated significant laboratory and clinical improvement following its use with no side effects. PATIENTS AND METHODS: All four patients were hospitalized with liver failure, coagulopathy, and bleeding that was controlled with fresh frozen plasma, platelets, and other therapies, as indicated. Their international normalization ratios (INR) ranged from 1.7 to 5.8 (normal 0.9-1.1). All four patients received rFVIIa for bleeding episodes that were not responding to their usual therapy, for procedures with a high risk of bleeding, or both. The dose of rFVIIa ranged from 0.067 to 0.3 mg/kg. The INR improved to normal or near normal in all four patients. In all cases, bleeding stopped within 10 minutes of receiving the rFVIIa, and there were no complications observed. CONCLUSIONS: rFVIIa provided significant benefit in these children with liver failure and severe coagulopathy, in terms of clinical and laboratory improvement in their bleeding and coagulation profiles. There were no obvious side effects from the rFVIIa. This drug may be an important tool in the treatment of children with liver failure and more study is needed to define the optimal dosing for children.

Blood Coagulation Disorders↗
PubMed2005

Can the stem cell mobilization technique influence CD34+ cell collection efficiency of leukapheresis procedures in patients with hematologic malignancies?

A total of 415 leukaphereses in 201 patients stimulated with growth factor (GF; n = 119) or chemotherapy-GF (n = 296) were studied to determine CD34+ cell collection efficiency (CE). The pre-apheresis leukocyte count was 1-93 x 10(9)/l (median 20), and peripheral blood CD34 count (PBCD34) was 1-1104/microl (median 19). The total number of CD34+ cells collected was 4-6531 x 10(6) (median 151); corresponding to 0.1-111.4 x 10(6) (median 2.3) per kg. There was strong correlation between PBCD34 and the number of CD34+ cells collected (r = 0.9; P < 0.0001). CE was 7-145% (median 46). On multiple regression analysis, a higher leukocyte count (P < 0.0001) was the most important predictor of lower CE. CE with leukocytes < 20 was 7-145% (median 53%) compared to 10-132% (median 40%) with leukocyte > or = 20 (P < 0.0001). In all, 61% of the apheresis procedures performed after chemotherapy-GF occurred when leukocytes were < 20 compared to 21% of those performed after GF alone (P < 0.0001). We conclude that mobilizing patients with the combination of chemotherapy and GF rather than GF alone leads to leukapheresis being performed when the leukocyte count is low -- in a range that results in optimum CD34+ cell CE. Autologous stem cells should be mobilized with chemotherapy-GF rather than GF alone whenever possible.

Adult↗
PubMed2005

Use of total leukocyte and platelet counts to guide stem cell apheresis in healthy allogeneic donors treated with G-CSF.

Healthy stem cell donors start leukapheresis 4-5 days after starting G-CSF based on the peripheral blood CD34+ cell count (PBCD34). Data from 137 harvests (68 donors) were analyzed to determine correlation between pre-apheresis leukocytes (11.0-94.8x10(9)/l; median 38.8) and platelets (49-374x10(9)/l; median 180), and PBCD34 (3-276/microl; median 40). PBCD34 correlated positively with leukocytes (r=0.48; P<0.0001) and platelets (r=0.40; P<0.0001). When pre-apheresis leukocytes were >or=25 and platelets were >or=100, PBCD34 and CD34+ collection were 5-276/microl (median 57) and 0.5-27.6x10(6)/kg (median 4.7), respectively; significantly higher than PBCD34 of 3-74/microl (median 17) and CD34+ collection of 0.2-8.9 x 10(6)/kg (median 2.2) when leukocytes were <25 and/or platelets were <100. With leukocytes >or=25 and platelets >or=100, PBCD34 was low (<20/microl) 8% of the time, compared to 57% of the time with leukocytes <25 and/or platelets <100 (P<0.0001). Our data suggest that it is not always necessary to measure PBCD34 to guide leukapheresis in healthy donors because pre-apheresis leukocytes and platelets >or=25 and >or=100, respectively, are associated with excellent mobilization. When blood counts do not meet these criteria, PBCD34 should be determined prior to initiation of apheresis.

Adolescent↗