PubMed Health⌕ Search

Biomedical subjects

N Anderson

Publications and source records attributed to N Anderson.

At least 19 recordsLinked to original sources

Mucor rouxii ultrastructure: cyclic AMP and actin cytoskeleton.

A comparative analysis of the effect of two compounds, dibutyryl-cyclic-AMP (dbcAMP) and latrunculin B, on the morphology and ultrastructure of the dimorphic fungus Mucor rouxii under aerobic growth conditions is presented. dbcAMP acts through the sustained activation of protein kinase A, and latrunculin B through the disruption of the actin cytoskeleton. Upon addition of these compounds to the growth medium at any stage of the germination process, cells lost polarised growth and switched to isodiametric growth. The effect was reversible. The morphologies, visualised by light microscopy or scanning electron microscopy (SEM), were alike. A switch from a rough to a smooth surface was observed by SEM when cells were repolarised by removal of the added compound. Ultrastructural changes under both conditions, as observed by transmission electron microscopy, were similar, the main feature being the enlargement of the cell wall, with irregular depositions, and detachment from the cell membrane. dbcAMP-treated cells showed a decrease in the number of glycogen granules compared with control and latrunculin B-treated cells. F-actin staining with fluorescein isothiocyanate-phalloidin showed that both dbcAMP- and latrunculin B-treated cells displayed a much lower fluorescence than control cells, with only a few pale plaques. The results suggest that the sustained activation of protein kinase A, which impairs polarised growth, might exert its effect through a modification of actin cytoskeleton organisation, very probably also involving an integrinlike pathway, as judged by the cell wall detachment and loss of cell adhesiveness of the dbcAMP-treated isodiametric cells.

Actins↗

Impact of a national external quality assessment scheme for breast pathology in the UK.

BACKGROUND: This article presents the results and observed effects of the UK National Health Service Breast Screening Programme (NHSBSP) external quality assurance scheme in breast histopathology. AIMS/METHODS: The major objectives were to monitor and improve the consistency of diagnoses made by pathologists and the quality of prognostic information in pathology reports. The scheme is based on a twice yearly circulation of 12 cases to over 600 registered participants. The level of agreement was generally measured using kappa statistics. RESULTS: Four main situations were encountered with respect to diagnostic consistency, namely: (1) where consistency is naturally very high-this included diagnosing in situ and invasive carcinomas (and certain distinctive subtypes) and uncomplicated benign lesions; (2) where the level of consistency was low but could be improved by making guidelines more detailed and explicit-this included histological grading; (3) where consistency could be improved but only by changing the system of classification-this included classification of ductal carcinoma in situ; and (4) where no improvement in consistency could be achieved-this included diagnosing atypical hyperplasia and reporting vascular invasion. Size measurements were more consistent for invasive than in situ carcinomas. Even in cases where there is a high level of agreement on tumour size, a few widely outlying measurements were encountered, for which no explanation is readily forthcoming. CONCLUSIONS: These results broadly confirm the robustness of the systems of breast disease diagnosis and classification adopted by the NHSBSP, and also identify areas where improvement or new approaches are required.

Breast Neoplasms↗

The NHS breast screening programme (pathology) EQA: experience in recent years relating to issues involved in individual performance appraisal.

BACKGROUND: The original role of the National Health Service breast screening programme (pathology) external quality assessment (EQA) scheme was educational; it aimed to raise standards, reinforce use of common terminology, and assess the consistency of pathology reporting of breast disease in the UK. AIMS/METHODS: To examine the performance (scores) of pathologists participating in the scheme in recent years. The scheme has evolved to help identify poor performers, reliant upon setting an acceptable cutpoint. Therefore, the effects of different cutpoint strategies were evaluated and implications discussed. RESULTS/CONCLUSIONS: Pathologists who joined the scheme improved over time, particularly those who did less well initially. There was no obvious association between performance and the number of breast cancer cases reported each year. This is not unexpected because the EQA does not measure expertise, but was established to demonstrate a common level of performance (conformity to consensus) for routine cases, rather than the ability to diagnose unusual/difficult cases. A new method of establishing cutpoints using interquartile ranges is proposed. The findings also suggest that EQA can alter a pathologist's practice: those who leave the scheme (for whatever reason) have, on average, marginally lower scores. Consequently, with the cutpoint methodology currently used (which is common to several EQA schemes) there is the potential for the cutpoint to drift upwards. In future, individuals previously deemed competent could subsequently be erroneously labelled as poor performers. Due consideration should be given to this issue with future development of schemes.

Breast Neoplasms↗

Corticosteroids for aneurysmal subarachnoid haemorrhage and primary intracerebral haemorrhage.

BACKGROUND: Corticosteroids, particularly dexamethasone, are commonly used for treatments in patients with subarachnoid haemorrhage (SAH) and primary intracerebral haemorrhage (PICH) despite the lack of evidence. OBJECTIVES: This review aimed: (1) to determine whether corticosteroid therapy reduces the proportion of patients who die or have a poor outcome at one to six months after the onset of SAH or PICH; (2) to determine whether corticosteroid therapy reduces the frequency of delayed cerebral ischaemia (DCI) in patients with SAH; (3) to determine the frequency of adverse effects of corticosteroid therapy in patients with SAH or PICH within six months of the onset of the event. SEARCH STRATEGY: We searched the Cochrane Stroke Group Trials Register (last searched November 2003). In addition, we searched MEDLINE (1966 to March 2004) and EMBASE (1980 to March 2004), and searched reference lists of relevant studies identified. We also made an attempt to identify any relevant ongoing and published or unpublished studies by contacting trialists and pharmaceutical companies. SELECTION CRITERIA: We sought to identify all randomised or quasi-randomised clinical trials of corticosteroid therapy, in patients with SAH or PICH, that have a placebo or standard strategy arm as control. Patients of any age and either gender with clinically (bed-side) diagnosed PICH and cerebrospinal fluid documented SAH were included in the analysis. The data were analysed both separately and combined for computed tomography (CT)/magnetic resonance imaging (MRI)/autopsy/angiography verified patients. DATA COLLECTION AND ANALYSIS: Data extracted from eligible clinical trials included: (1) death and poor outcome (death, severe disability, or vegetative state) within the first one to six months of the event onset (primary outcomes); (2) development of delayed cerebral ischaemia (as defined by the trialists) in patients with SAH; and (3) adverse effects of the treatment during the scheduled treatment or follow-up period (secondary outcomes). A pooled estimate of the effect size was computed, and the test for heterogeneity between trial results was carried out using The Cochrane Collaboration's Review Manager software, RevMan 4.2. Intention-to-treat analysis was carried out whenever possible. MAIN RESULTS: Eight trials that fulfilled the eligibility criteria were identified, with a total of 256 randomised patients in three SAH trials, and 206 patients in five PICH trials. The studies differed substantially with regard to the study populations and drugs, and methodological quality. The number of patients allocated to either hydrocortisone or fludrocortisone acetate treatment in patients with SAH, or to dexamethasone treatment in patients with PICH, was too small to make any definitive conclusions (confidence intervals were wide for any of the outcome estimates). AUTHORS' CONCLUSIONS: Overall, there is no evidence of a beneficial or adverse effect of corticosteroids in patients with either SAH or PICH. Confidence intervals are wide and include clinically significant effects in both directions.

Adrenal Cortex Hormones↗

Diagnosis and management of simple ovarian cysts: an audit.

Simple ovarian cysts are common. The aim of clinical management is to optimize the treatment of malignant and premalignant cysts while minimizing intervention for cysts likely to resolve spontaneously. In this retrospective study, ovarian cysts over 30 mm in diameter were detected in 90 women. Of this population, 75 were premenopausal, 13 postmenopausal, and two had undergone a hysterectomy. Thirteen women presented acutely. Family history of breast, ovary or colon cancer was not ascertained in any of the women. None had CA125 levels performed. In 22 cases, the cyst was aspirated; only 10 of these had follow-up ultrasound. Laparotomy was performed in 25 premenopausal women, the two perimenopausal women and eight postmenopausal women. Average cyst size was 71 mm (range 40-80 mm) in the laparoscopy group, and 72 mm (range 36-180 mm) in the laparotomy group. After initial diagnosis at ultrasound, a follow-up scan was performed 4-16 weeks later. The final diagnosis was ovarian neoplasm in 13 and hydrosalpinx in two. None had a malignancy. Documentation at ultrasound was often inadequate, and management of the women with an ovarian cyst was haphazard. Guidelines on management of simple ovarian cysts are likely to improve clinical practice.

Adolescent↗

Measurement error in computed tomography pelvimetry.

Computed tomography pelvimetry is still used in clinical practice. We wished to quantify observer error in order to assess the level of confidence with which pelvic measurements can be described as adequate or inadequate. Anteroposterior inlet, anteroposterior outlet, transverse inlet and interspinous distances were measured from 11 CT pelvimetry examinations by five observers at one institution. Three CT pelvimetries were measured by five observers at a second institution. Intraobserver and interobserver variation was assessed using analysis of variance. Reliability of measurements was assessed using intraclass correlation coefficient. Combined error was calculated to determine 95% confidence limits for published minimum recommended pelvic measurements. The standard error of measurement, combining all sources, for measurement of the bony dimensions of the pelvis were: for anteroposterior inlet, 2.0 mm; anteroposterior outlet, 6.9 mm; transverse inlet, 1.3 mm; and interspinous distance, 2.1 mm. The 95% confidence interval around the recommended anteroposterior outlet of 100 mm was 88.5-111.3 mm. Observer variation in measurement of anteroposterior outlet is so large as to make the measurement of doubtful clinical utility.

Analysis of Variance↗

Tie-stall design and its relationship to lameness, injury, and cleanliness on 317 Ontario dairy farms.

The objective of this study was to identify relationships between tie-stall design and selected cow-based injury, lameness, and cleanliness measurements. All lactating dairy cows (n = 17,893) from 317 Ontario tie-stall dairy farms were evaluated once between March and September 2003. Stall dimensions were recorded and cows were scored for neck and hock lesions, broken tails, back arch, hind claw rotation, and udder and hind limb cleanliness. Neck lesions were significantly associated with tie-rail height. Hock lesions were positively associated with presence of an electric trainer and hind limb and udder cleanliness and negatively associated with tie-chain length. A negative association was found between broken tails and tie-rail height and a positive association between broken tails and udder and hind limb cleanliness. As mean stall length increased, fewer cows had hind-claw rotation. Having more dirty cows was associated negatively with stall length and chain length, and positively associated with the presence of an electric trainer. Proportion of cows with clean udders increased with the percentage of cows with clean hind limbs and with tie-rail height. As the prevalence of clean udders increased the prevalence of broken tails decreased. This study provides insight into how tie-stall dimensions may influence aspects of dairy cow welfare. Application of these principles could improve tie-stall design.

Animal Welfare↗

Differences in diabetic co-morbidity between Aboriginal and non-Aboriginal people living in Bella Coola, Canada.

INTRODUCTION OBJECTIVES: (1) To identify which medical disorders are significantly associated with being a diabetic in the setting of an isolated, rural community; and (2) to determine if there are differences between Aboriginal and non-Aboriginal diabetics. METHODS DESIGN: population based retrospective chart review. STUDY POPULATION: people living in the Bella Coola Valley, Canada, and having a chart at the Bella Coola Medical Clinic as at September 2001. MAIN OUTCOME MEASURES: known diabetes related co-morbidity (retinopathy, nephropathy, coronary artery disease, peripheral vascular disease, neuropathy). RESULTS: There were 126 adult (>18 years old) diabetics living in the Bella Coola Valley. Prevalence rates for history of alcohol issues, retinopathy, coronary artery disease, cerebrovascular disease, peripheral vascular disease, peripheral neuropathy, hypertension, hypercholesterolemia, and nephropathy were 44%, 14%, 19%, 8%, 7%, 10%, 54%, 47%, and 7% respectively. For the 1597 non-diabetics living in the Bella Coola Valley, respective prevalence rates for these same co-morbidities were 20%, 0.3%, 2%, 1.5%, 1%, 1%, 10%, 6%, and 0.6%. The study did not demonstrate that Aboriginal people living in the Bella Coola Valley have an increased prevalence of diabetes associated co-morbidities over and above that found in the non-Aboriginal diabetic population. This was despite the fact the smoking rate was higher in the Aboriginal population. CONCLUSIONS: The development of diabetes in both Aboriginal and non-Aboriginal people living in the Bella Coola Valley was clearly associated with the presence of multiple co-morbidities, including hypertension, hypercholesterolemia, coronary artery disease, cerebrovascular disease, and neuropathy. Rates of diabetes associated co-morbidities were similar for both Aboriginal and non-Aboriginal diabetic populations. The authors speculate that a diet rich in fish oils (omega-3 fatty acids) accounted for the lower than expected rates of cardiovascular disease among this Aboriginal population.

Journal Article↗

Radial scar, complex sclerosing lesion and risk of breast cancer. Analysis of 175 cases in Northern Ireland.

BACKGROUND: Controversy exists over the nomenclature and clinical significance of radial scar/complex sclerosing lesion (RS/CSL) of the breast. A retrospective analysis of cases diagnosed from 1988 to 2001 in Northern Ireland was performed to determine if any clinical difference exists between the diagnoses of radial scar and complex sclerosing lesion, and establish if lesions suggestive of RS/CSL require excision and/or follow-up. PATIENTS: Patients with a diagnosis of RS/CSL from 1988 to 2001 were identified from the databases of the pathology laboratories serving specialist breast surgical units and the Northern Ireland Breast Screening Programme. RESULTS: True RS/CSL was confirmed in 175 of 230 cases. There was no difference between RS and CSL regarding associated pathology in the specimen. 16.9% of cases identified at symptomatic clinics were associated with carcinoma in situ, and 15.7% with invasive breast carcinoma, compared to 4.7 and 2.3%, respectively in the screen detected group. One later carcinoma was found. CONCLUSIONS: There is no clinical difference between the entities radial scar and complex sclerosing lesion. RS/CSL require excision due to their association with malignancy. In the absence of any independent risk factor for carcinoma no further follow-up of patients with RS/CSL is required.

Adult↗

NOD2/CARD15, TLR4 and CD14 mutations in Scottish and Irish Crohn's disease patients: evidence for genetic heterogeneity within Europe?

NOD2/caspase recruitment domain (CARD)15 variants are identified in up to 50% of Crohn's disease (CD) patients. Functional variants of toll-like receptor-4 (TLR4) and CD14 genes may also be relevant to disease pathophysiology. We aimed to assess the contribution of NOD2/CARD15, TLR4 and CD14 variants in Scottish and Irish CD patients. In all, 612 patients with well-characterised inflammatory bowel disease (252 Scottish CD, 247 Scottish UC, 113 Irish CD) and 304 controls were genotyped for variants of NOD2/CARD15 (1007fsinsC, G908R, R702W, P268S), TLR4 (A299G) and CD14 (T-159C). Genotype-phenotype analyses were performed. Variant 1007fsinsC (P=0.003) and G908R (P=0.008) but not R702W (P=0.269) alleles were more prevalent in Scottish CD (4.7, 1.8 and 7.1%, respectively) than Scottish control (2.3, 0.3 and 5.4%). CD allelic frequencies were lower than the series from Europe (P<0.00001) and North America (P<0.00001) but not Scandinavia (P<0.7). Associations were identified with age at diagnosis (P=0.002), ileal disease (P<0.02), penetrating disease (P=0.04) and inflammatory joint disease (P<0.02). TLR4 and CD14 variants did not differ between CD and controls. In conclusion, we present compelling evidence for genetic heterogeneity within Europe. These NOD2/CARD15 variants have a minor contribution in Scottish and Irish CD patients, consistent with an emerging pattern from Northern Europe.

Adult↗

CT-guided fine-needle aspiration of lung nodules: effect on outcome of using coaxial technique and immediate cytological evaluation.

PURPOSE: To evaluate the risk of pneumothorax during CT-guided fine-needle aspiration (FNA) of lung nodules with single needle and coaxial needle techniques and to assess the effect on diagnostic accuracy of immediate cytological examination of lung FNA samples. MATERIALS AND METHODS: This prospective study analysed 53 patients undergoing transthoracic FNA biopsy of lung. 36 cases were performed by a radiologist using a coaxial technique, with 17 cases performed by a radiologist using a direct single-needle method. Effect of technique on occurrence of pneumothorax was recorded. FNA samples from all the patients in the study were examined immediately on-site by a cytologist or MLSO to determine whether sufficient aspirate had been obtained. Provisional diagnosis at immediate examination was compared to final diagnosis following full pathological evaluation. RESULTS: Coaxial and non-coaxial groups were comparable for age and gender. Number of pleural passes was significantly lower in coaxial group (P < 0.01). Pneumothorax occurred in six (17%) of the 36 patients biopsied by coaxial technique, compared to four (24%) of the 17 patients by non-coaxial method (P = 0.55). Chest tube placement was required in four patients (11%) in the coaxial group, and two patients (12%) in the non-coaxial group (P = 0.85). A provisional cytological diagnosis was recorded for 74% of the patients in the study. 83% of the provisional reports were accurate on comparison with full pathology report. Specimen size was sufficient in 81% of cases. CONCLUSIONS: The use of coaxial technique for CT-guided lung FNA biopsy reduced the number of pleural passes but did not significantly reduce the occurrence of pneumothorax. Immediate cytological examination of FNA specimens provided an accurate provisional diagnosis in the majority of cases, and should be routinely employed.

Aged↗

Relationship of isolated fetal intracardiac echogenic focus to trisomy 21 at the mid-trimester sonogram in women younger than 35 years.

OBJECTIVE: To determine whether an isolated echogenic intracardiac focus in the fetal heart in the mid-trimester (16-24 weeks) in women aged 18-34 years of age is associated with trisomy 21. METHOD: This was a prospective population-based observational study. A search of all obstetric sonograms performed in our region from January 1997 to December 1999 was carried out. From 12,373 pregnancies we identified 267 cases of echogenic foci in the fetal heart. Trisomy 21 was detected in 38 deliveries (0.31%). An echogenic focus was seen in 193 of the 9167 women < 35 years of age who had an obstetric sonogram at 16-24 weeks' gestation, and an echogenic focus was seen in 67 of the 1968 women > 35 years. The study group comprised the 149 women aged 18-34 years who had an echogenic focus in the fetal heart as the only abnormality at an obstetric sonogram performed at 16-24 weeks' gestation. RESULTS: There were no abnormal outcomes or cases of trisomy 21 among the 149 pregnancies with an echogenic focus as an isolated finding in women aged 18-34 years (0% (95% confidence interval, 0.00-2.43)). The prevalence of isolated echogenic focus was 1.6% for women < 35 and 1.8% for women >or= 35 years old. Of the 25 fetuses with trisomy 21 undergoing an obstetric sonogram at any gestational age, five (20%) had an echogenic focus. An isolated echogenic focus was present in one fetus with trisomy 21 seen at 26 weeks' gestation in a 17-year-old mother. Echogenic foci were single and in the left ventricle in 84.7% of cases. CONCLUSION: An isolated echogenic focus in the fetal heart at mid-trimester ultrasound in women aged 18-34 years is not associated with increased risk for trisomy 21.

Adolescent↗

Near-field Raman spectroscopy using a sharp metal tip.

Near-field Raman spectroscopy with a spatial resolution of 20 nm is demonstrated by raster scanning a sharp metal tip over the sample surface. The method is used to image vibrational modes of single-walled carbon nanotubes. By combining optical and topographical signals rendered by the single-walled carbon nanotubes, we can separate near-field and far-field contributions and quantify the observed Raman enhancement factors.

Journal Article↗

Ultrasonic treatment of Cryptosporidium oocysts.

The effect of 20 kHz ultrasound on the viability of Cryptosporidium oocysts was investigated. More than 90% of the dispersed Cryptosporidium oocysts could be deactivated in about 1.5 min of continuous sonication. In order to apply this technique to large quantities of contaminated water, quantitative filtration and redispersion of Cryptosporidium oocysts were investigated and found to be easily achievable. The estimated cost of sonication showed that the ultrasound treatment of Cryptosporidium oocysts contaminated water could be a very effective means of "deactivating" Cryptosporidium oocysts.

Animals↗

The contribution of transfusion to HCV infection in England.

The English HCV lookback programme has identified some individuals with transfusion-transmitted HCV infection. The path from the collection of donations from HCV-infected donors to the identification of infected recipients was constructed. The probability of different outcomes at each branch was derived from data collected during this programme. This path of probabilities was then used to produce a complete estimate of the number of recipients infected by blood transfusions (dead and alive at the end of 1995) by re-entry of blood components that fell out of the lookback at various steps prior to recipient testing, and entry of components from HCV-infected donations that were never identified for lookback. Less than 14,000 recipients were estimated to have been infected with HCV during the decade prior to the start of donation testing. Over 60% of these were expected to have died by the end of 1995. Transfusion has infected a large group of individuals. However, this group constitutes a very small, and declining, proportion of all HCV infections in the population.

Blood Transfusion↗

The pre-operative identification of low-risk endometrialcancer: an audit of women treated in the South Island of New Zealand 1998-2000.

OBJECTIVE: To determine whether pre-operative investigations identify a group of patients with low-risk endometrial cancer, who do not require tertiary referral for surgical staging or pelvic radiotherapy. DESIGN: Retrospective chart review. SETTING: South Island of New Zealand gynaecological oncology services. SAMPLE: One hundred and forty consecutive patients with newly diagnosed endometrial cancer from 1988 to 2000. METHODS: The results of preoperative investigations were compared with the final pathology. MAIN OUTCOME MEASURES: Correlation of preoperative investigations with low risk disease. For the purpose of the study, women with grade 1 or 2 endometrioid tumours confined to the uterine body and less than 50% myometrial invasion were considered to have low risk disease. RESULTS: In total, 50 women had low risk disease. Only 53% of patients with grade 1 tumours on initial biopsy had low risk disease. Women who had a grade 1 tumour at biopsy and, an ultrasound report with an endometrial thickness of less than 20 mm, and no evidence of myometrial invasion, cervical involvement or adnexal metastasis had a 76% chance of having low risk disease. CONCLUSION: We were unable to accurately define the low risk group from pre-operative assessment.

Curettage↗

The integration of grazing management and summer treatments for the control of trichostrongylid infections in Merino weaners.

OBJECTIVE: To compare two strategies for the preparation of pastures that have reduced trichostrongylid infections during winter and spring for Merino weaners. DESIGN: A replicated field experiment was conducted over two successive years. A 'standard' strategy, comprising set-stocked wethers given anthelmintic treatments in late October and early February, was compared with a 'new' one in which intensive grazing for 1 month after each treatment and destocking for 1 or 2 months was integrated with the anthelmintic treatments. Paddocks prepared according to these strategies were set-stocked at 15 Merino weaners/ha from April to October inclusively. RESULTS: Contamination of pastures prepared according to the new strategy was substantially reduced compared to those of the standard strategy. Worm counts showed that on new strategy paddocks the numbers of trichostrongylid larvae, except Nematodirus spp, were reduced by 50 to 95% compared to standard strategy paddocks. Worm egg counts from the set-stocked weaners were reduced by about 50% on new strategy paddocks from April to October. Weaners grazing the new strategy paddocks grew significantly more clean wool (254 g, P = 0.01) and were significantly heavier in October (3.2 kg, P = 0.01) than weaners in the standard strategy paddocks. The improved production was attributable partially to better pasture growth early in winter and partially to reduced parasitism. CONCLUSION: The new strategy is a simple, practical and widely applicable example of the integration of grazing management with strategically timed anthelmintic treatments to reliably reduce trichostrongylid infections in weaners grazing during winter and spring.

Animal Feed↗