PubMed Health⌕ Search

Biomedical subjects

A R Wilson

Publications and source records attributed to A R Wilson.

At least 19 recordsLinked to original sources
PubMed2005

Anti-bacterial activity of Lactobacillus plantarum strain SK1 against Listeria monocytogenes is due to lactic acid production.

AIMS: The aim of this research was to investigate the potential of Lactobacillus plantarum strain SK1 for use as a biological control agent against Listeria monocytogenes and determine its mechanism of anti-listerial activity. METHODS AND RESULTS: Co-growth of Lact. plantarum SK1 and L. monocytogenes UMCC98 in MRS broth showed that anti-listerial activity of Lact. plantarum SK1 occurred during late log/early stationary phase of growth. This coincided with a reduction in broth pH to 4.26. Evidence obtained from the analysis of cell-free culture filtrates of strain SK1 grown in MRS broth using thin-layer chromatography and growth of L. monocytogenes in pH-adjusted culture filtrates suggested that the anti-listerial activity was due to lactic acid production alone. Trials of Lact. plantarum SK1 on radishes stored at 5 degrees C showed that it had statistically significant (P < 0.05) anti-listerial activity. CONCLUSIONS: The anti-listerial activity of Lact. plantarum SK1 was due to lactic acid production alone. A small-scale trial on radishes stored at 5 degrees C showed it to have significant anti-listerial activity in planta. SIGNIFICANCE AND IMPACT OF THE STUDY: This organism has potential as a biological control agent for L. monocytogenes.

Antibiosis↗
PubMed2001

The effects of pH and surface composition on Pb adsorption to natural freshwater biofilms.

Two dominant variables that control the adsorption of toxic trace metals to suspended particulate materials and aquatic surface coatings are surface composition and solution pH. A model for the pH-dependent adsorption of Pbto heterogeneous particulate surface mixtures was derived from experimental evaluation of Pb adsorption to laboratory-derived surrogates. The surrogate materials were selected to represent natural reactive surface components. Pb adsorption to both the laboratory surrogates and natural biofilms was determined in chemically defined solutions under controlled laboratory conditions. Pb adsorption was measured over a pH range of 5-8, with an initial Pb concentration in solution of 2.0 microM. The surface components considered include amorphous Fe oxide, biogenic Mn oxide produced by a Mn(II) oxidizing bacterium (Leptothrix discophora SS-1), Al oxide, the common green alga Chlorella vulgaris, and Leptothrix discophora SS-1 cells. A linearization of Pb adsorption data for each adsorbent was used to quantify the relationship between Pb adsorption and pH. The parameters for individual adsorbents were incorporated into an additive model to predict the total Pb adsorption in multiple-adsorbent natural surface coatings that were collected from Cayuga Lake, NY. Pb adsorption experiments on the natural surface coatings at variable pH were utilized to verify the additive model predictions based on the pH dependent behavior of the experimental laboratory surrogates. Observed Pb adsorption is consistent with the model predictions (within 1-24%) over the range of solution pH values considered. The experimental results indicate that the combination of Fe and biogenic Mn oxides can contribute as much as 90% of Pb adsorbed on Cayuga Lake biofilms, with the dominant adsorbent switching from Mn to Fe oxide with increasing pH.

Biofilms↗
PubMed2001

Growth pattern of ductal carcinoma in situ (DCIS): a retrospective analysis based on mammographic findings.

The aim of this study was to obtain information concerning the direction and rates of growth of ductal carcinoma in situ (DCIS). The previous mammograms of 124 women diagnosed with DCIS were examined. If in retrospect calcifications were present on the previous examination, the exact size and position were recorded on both diagnostic and previous imaging. The rates of change and direction of change in extent of calcifications were calculated. 39 women with a diagnosis of DCIS in retrospect had calcifications visible on both their current and prior examinations; these formed the study group. For individual clusters of calcification, change occurred along an axis to the nipple at a mean of 5.5 mm y(-1)and along an axis at 90 degrees to the nipple at 2.6 mm y(-1). Increase in calcifications along the axis to the nipple occurred at 2.6 mm y(-1)toward and 2.8 mm y(-1)away from the nipple. Increase in the axis to the nipple occurred at 1.8 mm y(-1)for low grade, 4.2 mm y(-1)for intermediate grade and 7.1 mm y(-1)for high grade. DCIS growth along an axis to the nipple occurs at over twice the rate of growth in the other direction(s) and growth toward and away from the nipple occurred equally. Growth rates increased with increasing nuclear grade of DCIS. These results validate nuclear grading of DCIS. Additionally, the results suggest that increased importance should be placed on identifying the 'nipple' and 'anti-nipple' margins of DCIS represented by calcifications for both surgical excision and pathological scrutiny.

Breast Neoplasms↗
PubMed2001

False-negative breast screening assessment: what lessons can we learn?

AIM: To review women who have had breast cancer diagnosed following previous assessment of a screen-detected mammographic abnormality in order to ascertain the frequency and characteristics of false-negative assessment. MATERIALS AND METHODS: The assessment process was reviewed in the study population of 28 women. This included the nature of the lesion recalled for assessment, additional mammography, clinical and ultrasound findings, and the results of fine needle aspiration cytology and needle histology. RESULTS: The frequency of false-negative assessment was approximately 0.56%. The median time between false-negative assessment and diagnosis of breast cancer was 33 months. The most common mammographic lesion resulting in false-negative assessment was micro-calcification seen in 12 cases (43%). Only five of these 12 cases had image-guided biopsy, the remainder were thought to be benign on magnification views. Other mammographic abnormalities were nine masses (32%), five architectural distortions (18%) and two asymmetric densities (7%). Of the 16 women with mammographic lesions other than micro-calcifications 10 had a normal ultrasound. CONCLUSION: Radiological interpretation of indeterminate micro-calcifications as benign or malignant is unreliable. An isolated cluster of micro-calcification requires image-guided core biopsy with representative micro-calcification obtained on specimen radiography. Further mammography done at assessment, particularly paddle compression views, should be carefully analysed to ensure areas of architectural distortion have truly resolved. If one imaging modality shows a significant abnormality and another does not the cases must be managed on the basis of the abnormal finding. Burrell, H.C.et al. (2001). Clinical Radiology56, 385-388.

Adult↗
PubMed2001

Predicting invasion in mammographically detected microcalcification.

AIM: To identify pre-operative factors which predict presence of invasive disease within mammographically detected malignant microcalcification. MATERIALS AND METHODS: A retrospective analysis was undertaken of 116 serial stereotactic core needle biopsies (SCNBs) performed on malignant mammographic calcification. Final surgical pathology was correlated with pre-operative features (clinical, radiological and core histology) in an attempt to predict the presence of an invasive component. RESULTS: Thirty-eight clusters contained invasive carcinoma. The sensitivity of SCNB for invasion was 55%. Clinical features, calcium morphology and cluster size were not shown to be predictive of invasive disease. Ductal carcinoma in situ (DCIS) of high grade on core histology and increasing number of calcifications were predictive of increased risk of invasion (high grade core biopsy DCIS and > 40 calcifications 48% invasive at surgical histology; high grade core biopsy DCIS and < 40 calcifications 15% invasive; non-high grade core biopsy DCIS 0% invasive). CONCLUSIONS: Identification of those clusters diagnosed as DCIS by percutaneous biopsy which are likely to harbour an invasive component is possible. It would seem reasonable to consider staging the axilla at therapeutic surgery in these patients.

Adult↗
PubMed2001

Detecting which invasive cancers at mammographic screening saves lives?

OBJECTIVES: Assessment of the features of primary operable breast carcinomas arising in women known to subsequently develop metastatic disease, to show for which invasive breast cancers earlier detection by mammographic screening is potentially beneficial. These data were applied to a separate series of screen detected cancers. METHODS: Features associated with the development of metastatic disease after a previous operable breast cancer were ascertained from examination of histological sections of the initial primary carcinoma and in particular the incidence of nodal positivity and definite vascular invasion. Trends in the frequency of nodal involvement and vascular invasion according to histological grade, invasive size, and tumour type were then examined in a further group of 573 screen detected invasive cancers to predict the likelihood of development of systemic disease in these women. RESULTS: Of 173 women who developed metastatic disease after a previous operable breast cancer, 79 (72%) had nodal metastases and 62 (59%) had definite vascular invasion. A high proportion (84%) had either lymph node metastases or vascular invasion or both. The absence of vascular invasion and nodal involvement in invasive breast cancer indicated a low risk of subsequent development of metastatic disease. In the screen detected group, grade 1 invasive cancers <20 mm in size and grade 2 and 3 cancers <10 mm in size had low rates of nodal involvement and vascular invasion. There was a gradual trend to small size, lymph node negativity, and less vascular invasion when comparing screen detected ductal carcinoma of no special type, tubular mixed carcinoma, and tubular carcinoma. Cancers with a lobular component tended to be larger and more often lymph node positive than ductal and no specific type carcinomas. CONCLUSIONS: These data suggest that identification of grade 1 cancers less than 20 mm in size and grade 2 and 3 cancers less than 10 mm in size at screening is likely to be beneficial, with a lower likelihood of developing metastatic disease from these lesions. The detection of tubular mixed carcinomas and ductal carcinomas of no specific type also appears beneficial. However the detection of tumours with lobular features at breast screening does not seem to significantly benefit the patient.

Breast Neoplasms↗
PubMed2001

Screen detected ductal carcinoma in situ (DCIS): overdiagnosis or an obligate precursor of invasive disease?

OBJECTIVES: Ductal carcinoma in situ (DCIS) represents 20%-25% of malignancy detected at mammographic screening. This study aims to clarify the value of detecting DCIS at mammographic screening by assessing its biological characteristics and by comparing screen detected DCIS with a series of symptomatic DCIS lesions. METHODS: 222 Screen detected and 151 symptomatic cases of pure DCIS were identified. Their histological grade and the prevalence of necrosis were ascertained and compared. RESULTS: Of the screen detected lesions 28 (13%) were low grade, 40 (18%) intermediate grade, and 153 (69%) high grade. Of screen detected lesions 186 (87%) were necrotic and 29 (13%) were not. Of the 151 symptomatic lesions 24 (16%) were low grade, 34 (23%) intermediate grade, and 89 (61%) high grade. Of symptomatic lesions 112 (75%) were necrotic and 36 (24%) were not necrotic. Screen detected DCIS was more often necrotic (p=0.008) than symptomatic DCIS. CONCLUSIONS: As most DCIS detected at screening is high grade and necrotic, aggressive investigation of suspicious microcalcification at mammographic screening is advocated. Given the biological features of screen detected DCIS, the existence of an upper limit for the detection of DCIS by the NHS breast screening programme seems to be inappropriate.

Adult↗
PubMed2000

Value of contralateral surveillance mammography for primary breast cancer follow-up.

Mammographic screening of the contralateral breast is often advocated during follow-up of women previously treated for primary operable breast cancer. The purpose of this study was to determine the value of this investigation. Between 1987 and 1995 a total of 5102 contralateral screening mammograms were performed biennially on 2511 women aged </= 70 years following treatment for primary operable breast cancer. Sixty-five metachronous contralateral breast cancers were identified: 21 (32%) at routine clinical examination, 24 (37%) at mammography, and 20 (31%) by patients between routine follow-up appointments. The prognostic features of metachronous cancers were better or similar to those of the first cancer in 59 of 65 (91%) cases. Because of the favorable prognostic characteristics of the contralateral cancer, mammographic screening may have contributed to the long-term survival of 16 of 26 women in whom the histologic characteristics of the first cancer predicted a good prognosis. The cancer detection rate with mammography for these women was 6.5 per 1000 contralateral mammogram investigations at a cost of pound3852 per cancer detected. The results of this study suggest that surveillance mammography of the contralateral breast is of value in women whose first cancer predicted a favorable prognosis.

Adult↗
PubMed2000

Letter 2

Explore the source record for details and available documents.

Biopsy, Needle↗
PubMed2000

When have mammographic calcifications been adequately sampled at needle core biopsy?

AIMS: To determine if the number of flecks of calcification retrieved at stereotaxic core needle biopsy or the number of core samples obtained containing calcification are related to biopsy sensitivity, and to determine how many calcifications or cores containing calcification the radiologist should aim to retrieve when sampling mammographic microcalcification. MATERIALS AND METHODS: A retrospective review was performed of core specimen radiographs from 57 consecutive patients who had stereotaxic core needle biopsies of impalpable malignant microcalcifications without an associated mammographic mass. The total number of calcifications retrieved and the numbers of cores containing calcification were correlated with findings at core and surgical histology. RESULTS: Increasing retrieval of calcification elements visible on specimen radiography was associated with increasing sensitivity of the biopsy. Five or more flecks of calcium gave an absolute sensitivity of 100%. Increasing numbers of core samples obtained containing radiographically demonstrable calcification was also associated with increasing sensitivity. Three or more cores containing calcium resulted in a 100% absolute sensitivity for malignancy. CONCLUSION: To ensure adequate sampling of calcification at core biopsy, an optimum of either three or more cores containing calcium or five or more flecks of calcium in total is required. Achieving this target ensures a high pre-operative diagnosis rate for malignant microcalcifications.Bagnall, M. J. C. (2000). Clinical Radiology 55, 548-553.

Aged↗
PubMed2000

Ultrasound guided core biopsy of suspicious mammographic calcifications using high frequency and power Doppler ultrasound.

AIM: The pre-operative diagnosis of suspicious mammographic microcalcifications usually requires stereotactic needle biopsy. The aim of this study was to evaluate if high frequency 13 MHz ultrasound (HFUS) and power Doppler (PD) can aid visualization and biopsy of microcalcifications. MATERIALS AND METHODS: Forty-four consecutive patients presenting with microcalcifications without associated mammographic or palpable masses were examined with HFUS and PD. Ultrasound-guided core biopsy (USCB) was performed where possible. Stereotactic biopsy was carried out when US-guided biopsy was unsuccessful. Surgery was performed if a diagnosis of malignancy was made on core biopsy or if the repeat core biopsy was non-diagnostic. RESULTS: Forty-one patients (93%) had ultrasound abnormalities corresponding to mammographic calcification. USCB was performed on 37 patients. In 29/37, USCB obtained a definitive result (78.4%). USCB was non-diagnostic in 4/9 benign (44.4%) and 4/28 (14.3%) malignant lesions biopsied. The complete and absolute sensitivities for malignancy using USCB were 85.7% (24/28) and 81% (23/28), respectively. USCB correctly identified invasive disease in 12/23 (52.2%) cases. There was no significant difference in the presence of abnormal flow on PD between benign and malignant lesions. However, abnormal PD vascularity was present in 43.5% of invasive cancer and was useful in directing successful biopsy in eight cases. CONCLUSION: The combination of high frequency US with PD is useful in the detection and guidance of successful needle biopsy of microcalcifications particularly where there is an invasive focus within larger areas of DCIS.

Biopsy, Needle↗
PubMed2000

Digital imaging improves upright stereotactic core biopsy of mammographic microcalcifications.

AIM: This comparative study was carried out to assess the effect of using digital images compared to conventional film-screen mammography on the accuracy of core biopsy of microcalcifications using upright stereotactic equipment. MATERIALS AND METHODS: The biopsy results from a consecutive series of 104 upright stereotactic 14-gauge core biopsies performed with conventional X-ray (Group A) were compared with 40 biopsies carried out using stereotaxis with digital imaging (Group B). In all cases specimen radiography was performed and analysed for the presence of calcifications. Pathological correlation was then carried out with needle and surgical histology. RESULTS: The use of digital add-on equipment increased the radiographic calcification retrieval rate from 55 to 85% (P < 0.005). The absolute sensitivity of core biopsy in pure ductal carcinoma in situ (DCIS) cases rose from 34 to 69% (P < 0.03), with the complete sensitivity increasing from 52 to 94% (P < 0.005). For DCIS with or without an invasive component the absolute sensitivity rose from 41 to 67% (P = 0.052), while the complete sensitivity was 59% before and 86% after the introduction of digital imaging (P < 0.04). CONCLUSION: Digital equipment improves the performance of upright stereotactic core biopsy of microcalcifications, giving a significantly increased success rate in accurately obtaining calcifications. This leads to an improvement in absolute and complete sensitivity of core biopsy when diagnosing DCIS.

Adult↗
PubMed2000

An investigation into why two-view mammography is better than one-view in breast cancer screening.

AIM: To determine why two-view mammography in screening for breast cancer is more effective than using a single medio-lateral oblique view. MATERIALS AND METHODS: In the United Kingdom Coordinating Committee on Cancer Research randomized trial of one- vs two-view mammography in breast cancer screening the oblique view was assessed by one radiologist and two views (oblique and cranio-caudal) assessed by another. For the present study the mammographic films were retrieved from the screening centres and assessed by three consultant radiologists. Mammographic films were available from 110 women; 87 had their breast cancer detected by both one and two views and in 23 it was missed by one view but detected using two views. Outcome measures were breast size, location and size of the cancer, mammographic features, presence of microcalcification and overall radiological assessment. RESULTS: Although 23 cancers were missed in the original trial when one view was used, only two were not visible on the oblique view. Cancers missed using a single oblique view (and only detected if the cranio-caudal view was available with the oblique) tended to be smaller by about 4 mm (P = 0.05), centrally located in the breast (P = 0.16), not spiculated or round, (P </= 0. 001) and lacked microcalcification (P = 0.15). Breast size and breast radiographic density were not significantly associated with breast cancer detection. CONCLUSIONS: The results provide the basis for the observation that two-view mammographic screening is more effective than one-view mammographic screening.Hackshaw, A. (2000). Clinical Radiology55, 454-458.

Breast Neoplasms↗
PubMed1999

Bilateral breast carcinomas: do they have similar mammographic features?

AIMS: This study compared the mammographic appearance, site and histological features of synchronous and metachronous bilateral breast carcinomas. METHODS: Site, type of abnormality and background pattern seen on the diagnostic mammograms of 63 women with bilateral breast carcinoma were compared. The histological type and grade of all the carcinomas were verified by histological review. RESULTS: There was a tendency for the contralateral tumour to have similar mammographic features to those of the initial tumour. In patients in whom the first carcinoma was visible purely as a mass, the contralateral carcinoma had a similar appearance in 82% (P < 0.001). When the original tumour showed mammographic calcification the contralateral tumour did so in 65% (P< 0.001). Normal mammography or calcification alone were seen almost exclusively in women with a dense background pattern (100% and 92% respectively) while masses and calcification with masses were seen in women with dense and fatty patterns (58% and 35% dense respectively). When the mammographic site of the contralateral tumour was compared with that of the first tumour no significant correlation could be demonstrated. There was a significant trend for contralateral carcinomas to be of the same histological grade (P < 0.005) but not histological type. CONCLUSIONS: Contralateral carcinomas often have a similar mammographic appearance to the first tumours. Two factors may be responsible: (i) the tendency for contralateral carcinomas to be of the same histological grade and (ii) the influence of mammographic background pattern on the radiological appearance of breast carcinoma. This knowledge may assist in the interpretation of follow-up mammography in patients with a previous breast carcinoma.

Adult↗
PubMed1999

Mammographic features of ductal carcinoma in situ (DCIS) present on previous mammography.

AIM: To review previous mammograms of women found later to have DCIS and identify features which may have been missed or misinterpreted as benign. METHODS: The previous mammograms of 50 women who developed DCIS were analysed. The mammographic features at diagnosis and on the prior mammograms were compared. RESULTS: 11 (22%) of the previous mammograms were in retrospect abnormal; 5 (45%) of these had previously been assessed for the abnormality. All showed microcalcification. The following features were commoner at diagnosis than on previous films; rod shaped calcification (64 vs. 27%, P = 0.03) and a ductal distribution of calcification (76 vs. 45%, P = 0.05). Predominantly punctate calcification (64 vs. 12%, P = 0.001) and less than 10 calcifications in the cluster (54 vs. 24%, P = 0.05) were more common on the previous films. No difference was found in the frequency of granular calcification, branching calcification, irregularity in density, size or shape of calcification between the two groups. CONCLUSION: Features of DCIS missed on previous mammography include small cluster size, less than 10 calcifications in the cluster, the absence of rod shaped calcifications, the absence of a ductal distribution and the presence of predominantly punctate calcification. Features frequently seen both at diagnosis and on previous films which might have allowed earlier diagnosis were granular calcifications which vary in size, density and shape in an irregularly shaped cluster. Focal clustered calcification deserves aggressive investigation.

Adult↗