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Biomedical subjects

I Brown

Publications and source records attributed to I Brown.

At least 19 recordsLinked to original sources

Improved prognosis of patients with intermediate- and poor-risk nonseminomatous germ cell tumours by optimizing combined treatment.

OBJECTIVE: To assess whether the optimal use of combined treatment with chemotherapy and appropriately timed surgical intervention by a specialized team might improve the outcome for patients with poor- and intermediate-prognosis (International Germ Cell Consensus Classification, IGCCC) nonseminomatous germ cell tumours (NSGCTs). PATIENTS AND METHODS: Between 1984 and 1998, 47 patients with intermediate (16) and poor prognosis (31) NSGCT were treated; 43 had a testicular and four a retroperitoneal primary. RESULTS: Of the 47 patients only seven (15%) had a complete radiological response after primary chemotherapy; 36 (77%) required surgery after chemotherapy (29 para-aortic lymphadenectomy, 13 resection of pulmonary metastases, two each excision of supraclavicular and retrocrural lymph nodes and one resection of brain metastases; 13 required surgery at more than one site). There was no surgical mortality, with postoperative wound pain the commonest morbidity. On pathology, the resected masses were mature teratoma in 13, necrosis in 12 and malignant disease in 11 patients, the resection being complete in 30. There were microscopically positive margins in the other six patients, all but one having viable residual cancer. Of the 47 patients, 18 needed treatment for relapse, with four having surgery for growing mature teratoma, six chemotherapy plus surgery and eight salvage chemotherapy alone. Of 31 patients, 22 (71%) with a poor and 13 of 16 with an intermediate prognosis were alive at a median (range) follow-up of 94 (41-171) months; of all 47, 34 (72%) remain in complete remission. Ten patients died from disease progression. The presence of residual malignant disease at the resection margin was significantly associated with poorer survival (hazard ratio 7.21, P = 0.0016). Prognostic factors, e.g. number of involved sites, IGCCC group and viable tumour in resected masses, were not significant. The 5-year overall and relapse-free survival (95% confidence interval) was 81 (69-93)% and 57 (43-71)%, respectively. CONCLUSION: The optimal delivery and timing of chemotherapy and surgical resection by a specialist team of oncologists, urological and cardiothoracic surgeons is critical in treating poor-risk NSGCT and might be responsible for improving the outcome of these patients. The detection of residual malignant disease after chemotherapy by positron emission tomography should be investigated to identify those who might benefit from further systemic treatment before complete surgical resection.

Adult↗

Measurement of thyroglobulin mRNA in peripheral blood as an adjunctive test for monitoring thyroid cancer.

AIMS: Monitoring treated patients with thyroid cancer for recurrent or metastatic disease is currently based upon the serial measurement of circulating plasma thyroglobulin (Tg) concentrations. However, the clinical usefulness of Tg immunoassays is limited by poor sensitivity and interference from anti-Tg antibodies. This study investigated whether the detection of Tg mRNA in peripheral blood, using reverse transcriptase polymerase chain reaction (RT-PCR), is of value in the biochemical surveillance of patients with thyroid cancer. METHODS: RNA was extracted from peripheral blood of five normal controls, six patients with abnormal thyroid function tests, and 28 patients who had undergone thyroidectomy for well differentiated thyroid cancer. From each, an 87 bp product from base pair 262 to 348 in the cDNA sequence of the thyroglobulin gene was amplified by RT-PCR. RESULTS: Tg mRNA was detected in normal individuals and patients with thyroid cancer. In the group of patients studied, identification of metastatic thyroid tissue by radioiodine scanning correlated better with Tg mRNA assay results than with serum Tg concentrations (accuracy 84% v 75%). No interference from circulating Tg antibodies was apparent. In patients studied prospectively over a 12 month period, there was a significant correlation between detectable Tg mRNA in peripheral blood and the presence or absence of metastatic disease, as demonstrated by radioiodine scanning. CONCLUSIONS: These results suggest that detection of Tg mRNA in blood is a more sensitive marker for metastatic thyroid disease than Tg immunoassay, and appears to be unaffected by the presence of circulating anti-Tg antibodies.

Adenocarcinoma, Follicular↗

Making the links between community structure and individual well-being: community quality of life in Riverdale, Toronto, Canada.

An inquiry into community quality of life was carried out within a framework that recognizes the complex relationship between community structures and individual well-being. Through use of focus groups and key informant interviews, community members, service providers, and elected representatives in a Toronto community considered aspects of their community that affected quality of life. Community members identified strengths of access to amenities, caring and concerned people, community agencies, low-cost housing, and public transportation. Service providers and elected representatives recognized diversity, community agencies and resources, and presence of culturally relevant food stores and services as strengths. At one level, findings were consistent with emerging concepts of social capital. At another level, threats to the community were considered in relation to the hypothesized role neo-liberalism plays in weakening the welfare state.

Community Networks↗

Organizational values in general practice and public involvement: case studies in an urban district.

A multiple case study design was used to explore dimensions of organizational values in general practice with respect to developing public involvement. The study was undertaken in an urban district in England with data collected through in-depth individual and focus group interviews with service providers and service users. Four general practice organizations were randomly selected for study after sorting all in the district according to their record of developing involvement activities. The case studies provide evidence of how organizational values can differ markedly in general practice in relation to ideas of public involvement, with consequences for the quantity and quality of activities for involving local people and service users. The differences manifest themselves in the beliefs and attitudes of service providers about the purpose of the organization and the types of relationships that are appropriate with service users and local people. Service users appear to be very perceptive to the underlying ethos and purpose to their practice organization and this affects their responsiveness to initiatives for their involvement. The dimensions of the different values found in the study appear to be essentially the same as a number of established empirical findings of variations in values in general practice: an orientation to a narrow medical role and to general practice as a business are associated with a low valuation of involvement; an orientation to teamwork and to a broader social role appear more congruent with the development of involvement. Power is a critical issue in this setting with evidence in the study of the dominance of the medical practitioners in establishing organizational values and the nature of public involvement activities.

Adolescent↗

Visualization of secreted Hrp and Avr proteins along the Hrp pilus during type III secretion in Erwinia amylovora and Pseudomonas syringae.

Pili are required for protein and/or DNA transfer from bacteria to recipient plant or bacterial cells, based on genetic evidence. However, it has never been shown directly that the effector proteins or DNA are localized along or inside the pili in situ. Failure to visualize an association of effector proteins/DNA with pili is the central issue in the debate regarding the exact function of pili in protein and DNA transfer. In this study, a newly developed in situ immunogold labelling procedure enabled visualization of the specific localization of type III effector proteins of Erwinia amylovora and Pseudomonas syringae pv. tomato along the Hrp pilus, but not along the flagellum or randomly in the intercellular space. In contrast, PelE, a pectate lyase secreted via the type II protein secretion system, was not associated with the Hrp pilus. These results provide direct evidence that type III secretion occurs only at the site of Hrp pilus assembly and that the Hrp pilus guides the transfer of effector proteins outside the bacterial cell, favouring the 'conduit/guiding filament' model.

Animals↗

Decreased vaginal disease in J-chain-deficient mice following herpes simplex type 2 genital infection.

J-chain-deficient (Jch(-/-)) mice were used to study the role of polymeric IgA (pIgA) in primary disease and protective immunity following genital herpes simplex type 2 (HSV-2) infection. Vaginal IgA in the Jch(-/-) mice was composed primarily of monomeric IgA and was not associated with secretory component (SC). In contrast, vaginal IgA in wild-type (WT) mice was predominantly polymeric and bound to SC. Following HSV-2 genital infection, the Jch(-/-) mice consistently exhibited fewer vaginal symptoms (P = 0.010) and mortality (P = 0.075) than did the WT mice. The variation in disease expression could not be explained by differences in local viral replication, since titers in vaginal wash fluid were comparable. To assess the effect of J chain deficiency on protective immunity, WT and Jch(-/-) mice were immunized intravaginally with attenuated HSV-2, challenged intravaginally with wild-type virus 5 weeks later, and evaluated for vaginal infection and neurological disease. Although the Jch(-/-) mice had reduced vaginal HSV-specific IgA and IgG levels following immunization, both WT and Jch(-/-) mice were protected from symptoms following wild-type virus challenge. We conclude that pIgA is not required for protective immunity against genital HSV-2 disease and that J chain deficiency offers some protection against symptoms following primary HSV-2 genital infection.

Animals↗

Liquid media development for Heterorhabditis bacteriophora: lipid source and concentration.

Lipids are important entomopathogenic nematode nutritional components because they are energy reserves and serve as indicators of nematode quality. The composition and concentration of the media lipid component determine bacterial and nematode yields. Heterorhabditis bacteriophora and its symbiont, Photorhabdus luminescens, were cultured in media containing various lipid sources. As lipid concentration increased from 2.5% to 8.0% (w/v), the final yield and productivity [calculated from the number of infective juveniles (IJ)] increased significantly from 2.1 x 10(5) IJ ml(-1) to 2.8 x 10(5) IJ ml(-1) (P < 0.05) and from 8.9 x 10(5) IJ l(-1) day(-1) to 11.8 x 10(5) IJ l(-1) day(-1) (P < 0.05), respectively. The nematode yield coefficient (IJ per gram of media), however, decreased from 2.8 x 10(6) to 2.2 x 10(6) (P < 0.05), while recovery increased from 45.3% to 58.0% (P < 0.05). Bacterial cell mass remained constant at 4.6 mg ml(-1) with changing lipid content (P > 0.05). The largest nematode yield (2.8 x 10(5) IJ ml(-1)) was achieved within 8 days, using a medium containing an 8% (w/v) olive and canola oil (50:50 w/v) combination. Moreover, developmental synchrony was achieved in this medium with 96% infective juveniles. In short, lipid sources rich in mono-unsaturated fatty acids and poor in saturated fatty acids produced optimal nematode growth.

Animals↗

Tumour necrosis factor-alpha (TNF-alpha) enhances lymphocyte migration into rheumatoid synovial tissue transplanted into severe combined immunodeficient (SCID) mice.

Adhesion mechanisms play a major role in the recruitment of peripheral blood lymphocytes (PBL) which characteristically infiltrate rheumatoid arthritis (RA) synovium and other chronically inflamed tissues. Through a sequential series of complex integrated adhesion and signalling events, 'multistep model of migration', specific subsets of PBL are recruited into inflamed tissues. In this process both leucocyte receptors and microvascular endothelial (MVE) counter-receptors play a critical role. The MVE in particular, during an inflammatory state, is the target of various inflammatory mediators that cause the up-regulation of several cell adhesion molecules (CAM). One of the most important factors known to be a powerful inducer of MVE CAM is TNF-alpha. Conversely, blocking TNF-alpha causes a down-modulation of CAM expression. To test directly the capacity of TNF-alpha to induce cell migration into RA synovium we adapted a model in which synovial grafts were implanted into SCID mice subcutaneously. Using this model we demonstrate that: (i) transplants remain viable and become vascularized and fed by mouse subdermal vessels; (ii) the mouse vasculature connects to the transplant vasculature which maintains the ability to express human CAM; (iii) intragraft injections of TNF-alpha up-regulate the expression of human CAM, following the down-regulation which occurred 4 weeks post-transplantation; and (iv) the up-regulation of graft CAM is associated with increased human PBL migration into the transplants. This study provides direct evidence in vivo of the capacity of TNF-alpha to induce cell migration. In addition, it provides the experimental background for the optimal use of this model.

Animals↗

The RPM1 plant disease resistance gene facilitates a rapid and sustained increase in cytosolic calcium that is necessary for the oxidative burst and hypersensitive cell death.

Early events occurring during the hypersensitive resistance response (HR) were examined using the avrRpm1/RPM1 gene-for-gene interaction in Arabidopsis challenged by Pseudomonas syringae pv. tomato. Increases in cytosolic Ca2+ were measured in whole leaves using aequorin-mediated bioluminescence. During the HR a sustained increase in Ca2+ was observed which was dependent on the presence of both a functional RPM1 gene product and delivery of the cognate avirulence gene product AvrRpm1. The sequence-unrelated avirulence gene avrB, which also interacts with RPM1, generated a significantly later but similarly prolonged increase in cytosolic Ca2+. Accumulation of H2O2 at reaction sites, as revealed by electron microscopy, occurred within the same time frame as the changes in cytosolic Ca2+. The NADPH oxidase inhibitor diphenylene iodonium chloride did not affect the calcium signature, but did block H2O2 accumulation and the HR. By contrast, the calcium-channel blocker LaCl3 suppressed the increase in cytosolic Ca2+ as well as H2O2 accumulation and the HR, placing calcium elevation upstream of the oxidative burst.

Aequorin↗

An inspiring case.

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Bronchial Fistula↗

211At-alpha-dose dependence of poly-ADP-ribosylation of human glioblastoma cells in vitro. Suitability in cancer therapy?

AIM: It was intended to test the biological response (poly-ADP-ribosylation of cellular proteins) of alpha-particles from extracellular 211At for enhanced damage to human glioblastoma cells in vitro and to discuss its suitability for potential application in therapy of high-grade gliomas. MATERIALS AND METHODS: Confluent cultures of human glioblastoma cells were exposed to different doses of alpha-radiations from homogeneously distributed extracellular 211At. Cellular poly-ADP-ribosylation of all proteins including histones was monitored since it is an indirect but sensitive indicator of chromatin damage and putative repair in both normal and malignant mammalian cells. RESULTS: A significant diminution (average 85.6%) in poly-ADP-ribosylation of total cellular proteins relative to that for non-irradiated glioblastoma cells was observed following 0.025 to 1.0 Gy alpha-radiations. In the dose range of 0.0025 to 0.01 Gy there was an increase with a maximum value of approximately 119.0% at 0.0025 Gy. Below 0.0025 Gy no change in poly-ADP-ribosylation was observed. CONCLUSIONS: Level of cellular poly-ADP-ribosylation of proteins at 0.025 to 1.0 Gy of alpha-radiation dose from 211At appears to cause enhanced damage by creating molecular conditions which are not conducive to repair of DNA damages in human glioblastoma cells in vitro. Therefore, it is assumed that clinical application of 211At at least in this dose range might enhance clinical efficacy in radiotherapy of cancer.

Alpha Particles↗

Extraosseous osteogenic sarcoma--a rare pediatric malignancy: case report and review of the literature.

BACKGROUND: Osteogenic sarcoma rarely occurs in soft tissues and generally affects individuals beyond the second decade of life. METHODS: The authors report a rare case of an extra osseous osteogenic sarcoma arising in the retroperitoneum of an adolescent, review the literature, and outline the diagnostic and therapeutic dilemmas. The role of adjuvant chemotherapy, using drugs used in managing bony osteosarcomas, is discussed. CONCLUSIONS: Retroperitoneal sarcomas may simulate ovarian teratomas. Careful consideration of the differential diagnosis of large cystic abdominal masses in adolescent females when size precludes adequate assessment of tumor mobility and imaging fails to demonstrate the ovaries is essential if these rare tumors are to be managed effectively.

Abdominal Neoplasms↗

A protective role for common p21WAF1/Cip1 polymorphisms in human ovarian cancer.

The objective of this study was to compare the frequency of two common p21WAF1/Cip1 gene polymorphisms in ovarian cancer patients with that in age-matched controls, from a population originating from Eastern Scotland. Both polymorphisms were found significantly less frequently in both the constitutive and tumour tissue DNA of ovarian cancer patients (3/65; 4.6%), than in that from geographically and age-matched controls (25/186; 13.4%) (p=0.0495, chi2). Furthermore, we found no p21WAF1/Cip1 gene mutations in any of the tumours, reflected by a relatively low degree of loss of heterozygosity (LOH) at the chromosomal region where the gene maps, providing further evidence that the p21WAF1/Cip1 gene is not mutated in ovarian cancer. The data suggest however, that there may potentially be a protective function for the two p21WAF1/Cip1 gene polymorphisms in the population under study.

Alleles↗

The development of a [211AT]-astatinated endoradiotherapeutic drug: part IV--late radiation effects.

PURPOSE: 6-[211At]-astato-MNDP is a high-LET endoradiotherapeutic drug that selectively targets to an oncogenically associated alkaline phosphatase isoenzyme expressed by certain tumors. A detailed histopathological study of the late tissue effects of its endogenous alpha-particle emissions has been carried out in a murine tumor model. MATERIALS AND METHODS: Thyroid-blocked male C57BI/10 mice bearing a s.c. transplanted rectal adenocarcinoma were treated with a single i.p. injection of 10-750 kBq 6-[211At]-astato-MNDP. Cured mice (131) were studied. Detailed autopsies and histological examinations were performed on all mice. The study was concluded after 756 days. RESULTS: Lymphoma, plasmacytoma, and intercurrent infections secondary to chronic pulmonary fibrosis were the most commonly found late manifestations of alpha-radiation exposure. Low grade B-cell non-Hodgkin's lymphoma occurred in 19 (24.7%) of 77 mice, 13-17 months after receiving 3.5-185 kBq 6-[211At]-astato-MNDP. The incidence of lymphoma alone and its latency was similar to that of the control population (23.3%). Treatment doses exceeding 200 kBq 6-[211At]-astato-MNDP, were associated with the development of soft tissue plasmacytoma in 7 (13%) of 54 mice, after 17-22 months. Generalized debilitation and nonspecific infections supervening pulmonary fibrosis significantly contributed to the late morbidity and mortality observed in mice treated with 300-750 kBq 6-[211At]-astato-MNDP. Dosimetry has afforded LD50/360 and LD50/420 estimates of 12-14 and 10-12 Cobalt-Gray equivalent (CGyE), respectively, for chronic lung damage. There was no histological evidence of chronic radiation damage to other critical healthy tissues. Normal thyroid morphology was preserved. CONCLUSIONS: Dose activities of 6-[211At]-astato-MNDP exceeding 300 kBq, were associated an increased risk of tumor induction and development of varying degrees of chronic pulmonary fibrosis implicated in the onset of terminal intercurrent infections. Within the therapeutic dose range 55-300 kBq 6-[211At]-astato-MNDP, mortality associated with the incidence of significant late radiation damage in critical normal tissues and latent carcinogenesis was less than 15%. Data from this murine model suggest that clinically relevant activities of 6-[211At]-astato-MNDP may be given without unacceptable toxicity.

Animals↗