Biomedical subjects
Publications and source records attributed to N Wilkinson.
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We report the results of interlaboratory collaborative trials of methods to detect oocysts of the protozoan parasite Cryptosporidium parvum on lettuce and raspberries. The trials involved eight expert laboratories in the United Kingdom. Samples comprised 30 g lettuce, and 60 g raspberries. Lettuce samples were artificially contaminated at three levels: low (8.5-14.2 oocysts), medium (53.5-62.6 oocysts), and high (111.3-135.0 oocysts). Non-contaminated lettuce samples were also tested. The method had an overall sensitivity (correct identification of all artificially contaminated lettuce samples) of 89.6%, and a specificity (correct identification of non-contaminated samples) of 85.4%. The total median percentage recovery (from all artificially contaminated samples) produced by the method was 30.4%. The method was just as reproducible between laboratories, as repeatable within a laboratory. Raspberry samples were artificially contaminated at three levels: low (8.5-26.8 oocysts), medium (29.7-65.7 oocysts), and high (53.9-131.3 oocysts). Non-contaminated raspberry samples were also tested. The method had an overall sensitivity (correct identification of all artificially contaminated raspberry samples) of 95.8%, and a specificity (correct identification of non-contaminated samples) of 83.3%. The total median percentage recovery (from all artificially contaminated samples) produced by the method was 44.3%. The method was just as reproducible between laboratories, as repeatable within a laboratory. The results of the collaborative trial indicate that these assays can be used effectively in analytical microbiological laboratories.
No standard method is available for detecting protozoan parasites on foods such as soft fruit and salad vegetables. We report on optimizing methods for detecting Cryptosporidium parvum on lettuce and raspberries. These methods are based on four basic stages: extraction of oocysts from the foodstuffs, concentration of the extract and separation of the oocysts from food materials, staining of the oocysts to allow their visualization, and identification of oocysts by microscopy. The concentration and separation steps are performed by centrifugation, followed by immunomagnetic separation using proprietary kits. Oocyst staining is also performed using proprietary reagents. The performance parameters of the extraction steps were extensively optimized, using artificially contaminated samples. The fully developed methods were tested several times to determine their reliability. The method to detect C. parvum on lettuce recovered 59.0+/-12.0% (n=30) of artificially contaminated oocysts. The method to detect C. parvum on raspberries recovered 41.0+/-13.0% (n=30) of artificially contaminated oocysts.
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The ovary is a common site of metastatic tumour. In many cases of ovarian metastasis there is a known history of malignancy but in other cases the ovarian tumour is the first manifestation of disease. In this review metastatic colorectal, appendiceal, gastric, breast, pancreatic and biliary tract, hepatocellular, renal, transitional and cervical carcinomas and metastatic malignant melanoma involving the ovary are discussed, as is the issue of synchronous ovarian and endometrial carcinomas. Peritoneal tumours, including primary peritoneal carcinoma, mesothelioma and intra-abdominal desmoplastic small round cell tumour, involving the ovary are also discussed, together with a variety of other rare, metastatic ovarian neoplasms. Many metastatic adenocarcinomas involving the ovary, especially those exhibiting mucinous differentiation, closely mimic primary ovarian adenocarcinomas with morphologically bland areas simulating benign and borderline cystadenoma. This is referred to as a maturation phenomenon. In recent years immunohistochemistry, especially but not exclusively differential cytokeratin (CK7 and CK20) staining, has been widely used as an aid to distinguish between a primary and secondary ovarian adenocarcinoma. While immunohistochemistry undoubtedly has a valuable role to play and is paramount in diagnosis in some cases, the results must be interepreted with caution, especially in mucinous tumours, and within the relevant clinical context. We feel the significance of differential cytokeratin staining is not always understood by histopathologists and this can result in erroneous interpretation. We critically discuss the value of immunohistochemistry and associated pitfalls with each tumour type described.
Most patients with esophageal cancer present with locoregional disease, and the optimal initial management is controversial. The current National Comprehensive Cancer Network (NCCN) practice guidelines support diverse treatment options for locoregional disease, including surgical resection alone, definitive chemoradiation therapy, and preoperative combined-modality (neoadjuvant/trimodality) therapy. Many cancer centers worldwide favor a neoadjuvant approach, although the evidence supporting this practice is inconsistent. A concise review of the literature is presented. The topics discussed do not necessarily reflect each author's opinions or clinical practices.
BACKGROUND: Immunological therapies have shown promising results in the treatment of endometriosis. Mycobacteria are one of the most common immune therapies used in other diseases. We have assessed the effects of mycobacteria in altering the ability of peripheral blood mononuclear cells (PBMCs) and natural killer (NK) cells to kill endometrial stromal cells using an in vitro model. This may have implications in the immunotherapy of endometriosis. METHODS: Primary cultures of endometrial stromal cells were grown from female patients and PBMCs were extracted from healthy female volunteers. Effector cells (PBMCs or NK cells) were exposed to varying concentrations of mycobacteria before their ability to kill cultured endometrial cells was tested using a 51Cr-release assay. RESULTS: Treatment of effector cells with the Connaught Substrain Bacillus of Calmette and Guérin (BCG) led to increased killing of target cells by PBMCs and NK cells. The optimal concentration for treatment of effector cells with Connaught BCG was approximately 0.1 multiplicities of infection (m.o.i.). There was a trend towards increased killing after treatment with Pasteur BCG. CD56+ (NK) cells treated with BCG at 0.1 m.o.i. showed increased killing of target cells compared with untreated effector cells. CONCLUSIONS: Endometrial stromal cells are susceptible to killer cells activated by mycobacteria. This in vitro work suggests a possible role for mycobacteria in the immunotherapy of endometriosis.
PROBLEM: To assess the effects of mycobacteria and inflammatory cytokines on proliferation of endometrial stromal cells. An effect on endometrial stromal cell proliferation in vitro may suggest a similar effect on endometriotic cells in vivo. METHOD OF STUDY: Primary cultures of endometrial stromal cells were grown from female volunteers. Proliferation of cells was assessed by cell counting and incorporation of tritiated thymidine after exposure to mycobacteria or inflammatory cytokines. RESULTS: When assessed by cell counting, stromal cell growth was reduced following treatment with Connaught Bacillus of Calmette and Guérin (BCG) and Pasteur BCG: Mycobacterium smegmatis demonstrated a cytotoxic effect. Addition of the cytokines interferon (IFN)-gamma or tumour necrosis factor (TNF)-alpha at high concentrations led to a reduction in cell growth by 24 hr in two of three cell lines. A reduction in proliferation was also found when assessed by tritiated thymidine incorporation, which was statistically significant for Connaught BCG and M. smegmatis. CONCLUSIONS: Endometrial stromal cells are susceptible to the anti-proliferative effects of mycobacteria. The BCG and other mycobacteria are known immunomodulators in other disease conditions. Further work is required to assess whether these in vitro effects might translate into a useful therapy for endometriosis.
Chemoradiation therapy is used widely for locoregional esophageal cancer. Patients with persistent disease may benefit from surgery. Preoperative esophagoscopy can identify persistent tumor but its accuracy is uncertain. The primary objective of this study is to assess the extent of agreement between esophagoscopy and surgical pathology in patients treated with neoadjuvant chemoradiation. A retrospective chart review of patients who underwent chemoradiation, preoperative endoscopy and surgery from January 1996 to December 2002 was performed. Cohen's kappa statistic was used to measure the degree of agreement between findings at endoscopic biopsy and surgical pathology. Thirty cases were identified. All patients received chemoradiation followed by surgical resection. There was insufficient agreement between tumor size (kappa 0.25, standard error 0.17, P = 0.07) and appearance (kappa 0.19, standard error 0.18, P = 0.14). Preoperative endoscopy revealed atypia/inflammation in 15 cases and dysplasia in eight. Of these 23 cases, 11 were adenocarcinomas at surgery. Only nine patients had concurrence between surgical pathology and endoscopy. The positive and negative predictive values of esophagoscopy for identifying residual tumor were 100% and 11%, respectively. Our data suggests that after chemoradiation, esophagoscopy is unreliable for excluding residual disease. The roles of other modalities need to be explored.
Ovarian clear cell carcinoma (OCCC) accounts for a small but significant proportion of all ovarian cancers and is a distinct clinical and pathological entity. It tends to be associated with poorer response rates to chemotherapy and with a worse prognosis. Little is known about possible underlying genetic changes. DNA extracted from paraffin-embedded samples of 18 pure OCCC cases was analysed for genetic imbalances using comparative genomic hybridisation (CGH). All of the 18 cases showed genomic alterations. The mean number of alterations detected by CGH was 6 (range 1-15) indicating a moderate level of genetic instability. Chromosome deletions were more common than amplifications. The most prominent change involved chromosome 9 deletions in 10 cases (55%). This correlates with changes seen in other epithelial ovarian cancers. This deletion was confirmed using microsatellite markers to assess loss of heterozygosity (LOH) at four separate loci on chromosome 9. The most distinct region of loss detected was around the IFNA marker at 9p21 with 41% (11 out of 27 cases) LOH. Other frequent deletions involved 1p (five out of 18; 28%); 11q (four out of 18; 22%) and 16 (five out of 18; 28%). Amplification was most common at chromosome 3 (six out of 18; 33%); 13q (four out of 18; 22%) and 15 (three out of 18; 17%). No high-level amplifications were identified. These features may serve as useful prognostic indicators in the management of OCCC.
A group of therapies with exciting potential has emerged for children and young people with severe juvenile idiopathic arthritis (JIA) uncontrolled by conventional disease modifying drugs. Theoretical understanding from molecular biologic research has identified specific targets within pathophysiological pathways that control rheumatoid arthritis (RA) and JIA. This review identifies the pathways of autoimmunity to begin to show how biologic agents have been produced to replicate, mimic, or block culpable molecules and so promote or inhibit cellular activity or proliferation. Of these agents, cytokine antagonists have shown greatest promise, and early clinical studies of tumour necrosis factor (TNF) blockade have identified dramatic clinical benefit in many children with JIA. However, as will also be discussed, overlap of pathways within a complex immune system makes clinical response unpredictable and raises additional ethical and administrative concerns.
Smooth muscle tumours of the uterus are common and the majority are benign leiomyomas. However, there are some tumours which exhibit unusual morphological features or growth patterns that cause difficulty in their distinction from malignant neoplasms and those with endometrial stromal differentiation. Such lesions are reviewed in this article with detailed descriptions of their morphology, differential diagnosis and correlation with biological behaviour.
OBJECTIVES: The primary objective was to investigate the safety of recombinant human granulocyte colony stimulating factor (rhG-CSF) for the treatment of very low birthweight infants (VLBW) with sepsis and relative neutropenia, specifically with regard to worsening of respiratory distress and thrombocytopenia and all cause mortality. Secondary objectives were to evaluate duration of ventilation, intensive care, and antibiotic use as markers of efficacy. DESIGN: Neonates (< or = 28 days) in intensive care, with birth weights of 500-1500 g, absolute neutrophil count (ANC) of < or = 5 x 10(9)/l, and clinical evidence of sepsis, were randomly assigned to receive either rhG-CSF (10 microg/kg/day) administered intravenously (n = 13), or placebo (n = 15) for a maximum of 14 days, in addition to standard treatment and antibiotics. All adverse events, oxygenation index, incidence of thrombocytopenia, all cause mortality, duration of ventilation, intensive care and antibiotic treatment, and ANC recovery were compared between the two groups. RESULTS: Adverse events and oxygenation index were not increased by, and thrombocytopenia was not attributable to, treatment with rhG-CSF. At 6 and 12 months postmenstrual age, there were significantly fewer deaths in the group receiving rhG-CSF (1/13 v 7/15; p < or = 0.038). There was a non-significant trend towards a reduction in duration of ventilation, intensive care, and antibiotic use in the rhG-CSF group. There was a significantly more rapid increase in ANC in the rhG-CSF treated babies (p < 0.001). CONCLUSIONS: In a small randomised placebo controlled trial in a highly selected group of neonates, adjuvant treatment with rhG-CSF increased ANC rapidly, and no treatment related adverse events were identified. Mortality at 6 and 12 months postmenstrual age was significantly lower in the treatment group. A large trial investigating efficacy in a similar group of neonates is warranted.
PURPOSE: To assess image-guided peritoneal core biopsy for the diagnosis of tumor type and treatment of patients with peritoneal carcinomatosis. MATERIALS AND METHODS: Thirty-five women (age range, 47-85 years; mean age, 69 years) prospectively identified in a gynecologic oncology center underwent 18-gauge core biopsy in omental cake (n = 25), peritoneal (n = 7), or adnexal (n = 3) sites. No complications of biopsy occurred. Standard hematoxylin-eosin analysis of the biopsy cores was supplemented by immunohistochemical markers to CA-125, carcinoembryonic antigen, cytokeratin 7, and cytokeratin 20. Diagnoses were validated with further multidisciplinary review, subsequent surgery, and response to specific chemotherapy. RESULTS: In 27 (77%) of the 35 women, a confident primary site diagnosis was obtained with standard hematoxylin-eosin analysis of core biopsy material from the following sites: ovary (n = 22), breast (n = 2), colon (n = 2), and lymphoma (n = 1). The finding at hematoxylin-eosin analysis in another seven (20%) women was poorly differentiated adenocarcinoma with no definite primary site but with an immunohistochemical profile suggesting ovarian cancer (CA-125 positive, carcinoembryonic antigen negative, cytokeratin 7 positive, cytokeratin 20 negative). There was one false-negative biopsy result. CONCLUSION: Image-guided peritoneal core biopsy with hematoxylin-eosin analysis supplemented with immunohistochemical analysis is a simple, safe, and accurate technique for providing site-specific diagnoses in women with undiagnosed peritoneal carcinomatosis.
A series of studies were performed, using poliovirus, to ascertain the potential for enteric pathogenic viruses to survive on various foodstuffs. The extraction protocols, which could be performed in just a few hours, were developed for use with quantities of food that would normally constitute a portion for consumption. The protocols were based on elution of viruses from food surfaces, followed by differential centrifugation to remove food debris and concentrate viruses. The studies were mostly performed using fresh produce stored at refrigeration temperature for 2 weeks or so, which was considered to represent the maximum time elapsing between purchase and consumption. Each food sample was inoculated with a viral suspension, and samples were analyzed immediately and at intervals throughout the experiment. Statistical analyses were performed on the results, and the decimal reduction times (D-values), or number of days after which the initial virus numbers had declined by 90%, were calculated. In summary, the resulting D-values were as follows: lettuce, 11.6 days; green onion, no decline; white cabbage, 14.2 days; fresh raspberries, no decline; and frozen strawberries, 8.4 days. The results showed that enteric viruses may persist on fresh fruit and vegetables for several days under conditions commonly used for storage in households. Therefore, if contamination has occurred before purchase, there will always be a risk of infection from consumption of the food.
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We studied the predictive performance of a dynamic modelling approach, combined with predictions from the Food MicroModel software, applied to the growth of Listeria monocytogenes and Salmonella in pasteurised milk, chicken liver pâté and minced chicken, under constant as well as fluctuating temperatures. We found that, in general, the accuracy of a prediction under fluctuation temperature was similar to that under constant temperature. Generally, there was a good agreement between predictions and observations. However, the growth of Listeria monocytogenes in pasteurised milk was inhibited largely by the natural flora present.
AIM: To illustrate unusual patterns of isolated supradiaphragmatic presentation and relapse of papillary serous adenocarcinoma of the ovary. METHODS: Retrospective study of five women (26-57 years) managed by a specialist gynaecological oncology unit. RESULTS: Three women relapsed in the neck, mediastinal or axillary nodes 3 to 5 years after complete abdomino-pelvic remission. Two women presented with pleural or cervical lymph node metastases respectively 2 and 13 years before the primary pelvic tumour was discovered. Clinical presentations in these five women mimicked metastatic thyroid and breast cancer and mesothelioma. In four of the five woman supradiaphragmatic nodal disease was heavily calcified. CONCLUSION: Women with papillary serous ovarian cancer may develop supradiaphragmatic disease without evidence of peritoneal metastasis or primary pelvic tumours. Isolated supradiaphragmatic relapse may occur many years after complete remission of abdomino-pelvic disease. Calcification in supradiaphragmatic lymph nodes should not be assumed to be due to old granulomatous disease as this may be the only clue to relapsing disease. Review of prior histology and use of immunohistochemical stains were valuable in diagnosis of these cases.