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Biomedical subjects

M C Bell

Publications and source records attributed to M C Bell.

At least 19 recordsLinked to original sources
PubMed2006

Pollination of greenhouse tomatoes by the Australian bluebanded bee Amegilla (Zonamegilla) holmesi (Hymenoptera: Apidae).

The pollination effectiveness of bluebanded bees of the species Amegilla (Zonamegilla) holmesi Rayment (Hymenoptera: Apidae) was evaluated in tomato plants, Lycopersicon esculentum Miller (Solanaceae), cultivated in two greenhouse chambers. Bluebanded bee pollination was compared with mechanical pollination and no supplementary pollination. Pollination effectiveness was compared between treatments by using the percentage of fruit set, fruit weight, fruit diameter, fruit roundness, and the number of seeds per fruit. Both the bluebanded bee pollination and the mechanical pollination treatments significantly increased fruit set, individual fruit weight, and diameter compared with the control treatment. Fruit were also significantly rounder and contained significantly more seeds. Positive correlations were found for fruit weight versus seed number, maximum diameter versus seed number and minimum diameter versus seed number. We conclude that the use of A. holmesi for pollinating greenhouse tomatoes in Australia may be an effective alternative to the use of mechanical pollination.

Animals↗
PubMed2004

Sustainable development of urban transport systems and human exposure to air pollution.

DAPPLE (Dispersion of Air Pollution and Penetration into the Local Environment, http://www.dapple.org.uk) is a major research project that will provide the understanding necessary to assess the sustainability of urban road transport in terms of exposure to traffic-related air pollution as an alternative to current indicators based on emissions, roadside, or far-from-road air pollution levels. The methodology is described, which combines on-street and laboratory measurement with modelling of the movement of air, vehicles, and vehicle exhaust emissions. The relationship between this kind of assessment and more realistic indicators of sustainability is discussed. The value of large-scale interdisciplinary research in this area is thus demonstrated.

Air Movements↗
PubMed2004

Characteristics and health implications of fine and coarse particulates at roadside, urban background and rural sites in UK.

Recent studies have pointed to evidence that fine particles in the air could be significant contributors to respiratory and cardiovascular diseases and mortality. Epidemiologists looking at the health effects of particulate pollution need more information from various receptor locations to improve the understanding of this problem. Detailed information on temporal, spatial and size distributions of particulate pollution in urban areas is also important for air quality modellers as well as being an aid to decision and policy makers of local authorities. This paper presents a detailed analysis of temporal and seasonal variation of PM(10) and PM(2.5) levels at one urban roadside, one urban background and one rural monitoring location. Levels of PM(10), PM(2.5) and coarse fraction of particulates are compared. In addition, particulate levels are compared with NO(2) and CO concentrations. The study concludes that PM(10) and PM(2.5) are closely related at urban locations. Diurnal variation in PM(2.5)/PM(10) ratio shows the influence of vehicular emission and movement on size distribution. This ratio is higher in winter than in summer, indicating a build-up or longer residence time of finer particulates or washout due to wet weather in winter. In the second part of this study, a disease burden analysis is carried out based on the dose-response relationships recommended by the UK Committee on the Medical Effects of Air Pollution. The disease burden analysis indicates that if Marylebone Road (MR) levels of PM(10) were prevalent all over London, it will result in around 2.5% increase in death rates due to all causes. Whereas, if Bloomsbury (BB) levels were prevalent in London, which is more likely to occur as this is more representative of the urban background environment to which people in London are likely to be exposed, the corresponding increase would be around 1.7%. Considering this, in London, at Bloomsbury levels, 973 deaths and 1515 respiratory hospital admissions (RHA) are attributable to PM(10) while 2140 RHA are attributable to NO(2). After deducting the disease burden due to background levels at Rochester (RC), PM(10) emission caused by anthropogenic activities in London equates to 273 additional deaths and 410 additional RHA, while NO(2) account for additional 1205 incidences of RHA.

Air Pollutants↗
PubMed2003

Polymorphisms in the interleukin 10 gene promoter are associated with susceptibility to aggressive non-Hodgkin's lymphoma.

Interleukin-10 (IL-10) is mainly an anti-inflammatory cytokine produced by a number of cells including normal and neoplastic B cells. It has been implicated in autoimmunity, transplantation tolerance and tumourigenesis. Polymorphisms in the IL-10 gene promoter genetically determine inter-individual differences in IL-10 production. The aim of this study was to determine whether polymorphisms in the IL-10 gene promoter play a role in predisposing an individual to lymphoma. We analysed the frequencies of three single base substitutions in the IL-10 promoter in patients with aggressive lymphoma (B-cell DLCL n = 46, other aggressive histologies n = 17), Hodgkin's disease (n = 44) or low/intermediate grade lymphoma (n = 46), compared to healthy controls. The frequency of the low-IL-10 producing AA allele (at position -1082) was significantly higher in patients with aggressive lymphoma compared to controls (p = 0.0344, Odds ratio 1.974, 95% C.I 1.066-3.655). Similarly, the frequency of the low IL-10 producing ATA or the intermediate-IL-10- producing ACC haplotype was significantly higher in patients with aggressive disease compared to controls (p = 0.0255, Odds ratio 1.647, 95% C.I 1.077-2.518). No association was found between IL-10 genotypes and Hodgkin's disease or less aggressive forms of lymphoma. Thus, polymorphisms in the IL-10 gene promoter which are associated with a low IL-10 producing phenotype may influence susceptibility to aggressive forms of lymphoma or may contribute to the pathogenesis of this disease.

Case-Control Studies↗
PubMed2001

Topotecan concomitant with primary brachytherapy radiation in patients with cervical carcinoma: a phase I trial.

OBJECTIVE: The aim of this study was to assess the toxicity of concomitant topotecan and radiation therapy in a Phase I study. Primary treatment for cervical carcinoma usually consists of surgery or radiation, with chemotherapy used in a neoadjuvant or concomitant fashion. There are in vitro data to suggest that topotecan is a radiosensitizing agent. METHODS: Six patients with cervical cancer were recruited to this study. All patients had completed whole pelvic radiation therapy and were scheduled for low-dose brachytherapy. The patients were administered topotecan IV during their low-dose brachytherapy. The initial dose of topotecan was 0.5 mg/m2/day for 5 days concomitant with low-dose brachytherapy for two brachytherapy applications. RESULTS: Three patients were accrued to the initial dose level. No major toxicity was noted at this dose level. Three patients were treated at the 1.0 mg/m2/day dose level; however, significant toxicity was noted at this level. (Two patients experienced grade 4 and one a grade 3 hematologic toxicity). CONCLUSION: Significant marrow toxicity was noted with concomitant topotecan and intracavitary radiation at 1.0 mg/m2/day. The maximum tolerated dose in this trial was 0.5 mg/m2/day for 5 days of topotecan concomitant with low-dose brachytherapy.

Adenocarcinoma↗
PubMed2000

HIV+ patients have increased lymphocyte infiltrates in CIN lesions.

OBJECTIVE: The objective of our study was to analyze immunocyte infiltrates in CIN lesions from HIV+ patients to assess whether local immunosuppression, defined as a decrease in T cell infiltrates, could explain the aggressive nature of CIN in HIV-infected patients. MATERIALS AND METHODS: Cervical tissue was obtained from 6 HIV+ CIN patients, 6 HIV- CIN patients, who underwent LLETZ (large loop excision of the transformation zone) for CIN, and 17 normal patients who underwent hysterectomy for benign indications. The following cell surface markers were analyzed: CD20 (B cells), CD4 (T helper cells), and CD8 (T suppressor/cytotoxic cells). Each tissue section was visualized with a Leica microscope at 400x and the image was captured for analysis by Harmony Group image analysis software. RESULTS: A significantly higher number of lymphocytes (both B and T cells) was detected in the stroma of HIV+/CIN tissue compared to either HIV-/CIN or normal tissue. There was also a significant increase in CD8+ cells in the HIV+/CIN group compared to HIV-/CIN or normal tissue. There was a trend toward a decreased CD4+/CD8+ ratio in the HIV+/CIN compared to the other two groups; however, this did not reach statistical significance. CONCLUSIONS: This study indicates that HIV+/CIN cervical tissue has a greater number of tissue lymphocytes recruited to the neoplastic site compared to HIV- individuals. In addition, HIV+ patients may have a decreased CD4/CD8 ratio in locally infiltrating immunocytes in CIN lesions. The local immunomodulatory effects of HIV may be detectable early in infection and therefore may explain the aggressive nature of CIN in the HIV+ patient.

CD4-CD8 Ratio↗
PubMed2000

Placebo-controlled trial of indole-3-carbinol in the treatment of CIN.

OBJECTIVE: Most precancerous lesions of the cervix are treated with surgery or ablative therapy. Chemoprevention, using natural and synthetic compounds, may intervene in the early precancerous stages of carcinogenesis and prevent the development of invasive disease. Our trial used indole-3-carbinol (I-3-C) administered orally to treat women with CIN as a therapeutic for cervical CIN. METHODS: Thirty patients with biopsy proven CIN II-III were randomized to receive placebo or 200, or 400 mg/day I-3-C administered orally for 12 weeks. If persistent CIN was diagnosed by cervical biopsy at the end of the trial, loop electrocautery excision procedure of the transformation zone was performed. HPV status was assessed in all patients. RESULTS: None (0 of 10) of the patients in the placebo group had complete regression of CIN. In contrast 4 of 8 patients in the 200 mg/day arm and 4 of 9 patients in the 400 mg/day arm had complete regression based on their 12-week biopsy. This protective effect of I-3-C is shown by a relative risk (RR) of 0.50 ((95% CI, 0. 25 to 0.99) P = 0.023) for the 200 mg/day group and a RR of 0.55 ((95% CI, 0.31 to 0.99) P = 0.032) for the 400 mg/day group. HPV was detected in 7 of 10 placebo patients, in 7 of 8 in the 200 mg/day group, and in 8 of 9 in the 400 mg/day group. CONCLUSIONS: There was a statistically significant regression of CIN in patients treated with I-3-C orally compared with placebo. The 2/16 alpha-hydroxyestrone ratio changed in a dose-dependent fashion.

Administration, Oral↗
PubMed2000

Rheumatoid synovial fluid contains bioactive leukemia inhibitory factor with cartilage degrading activity--another target for chondroprotective intervention.

OBJECTIVE: To determine if the procatabolic activity of inflammatory synovial fluids (SF) from patients with rheumatoid arthritis (RA) could be attenuated by the cytokine antagonists murine leukemia inhibitory factor (LIF) binding protein (mLBP) and interleukin 1 receptor antagonist (IL-1ra). METHODS: Pig articular cartilage explants were cultured in the presence of either 20% v/v rheumatoid (RA) or osteoarthritic (OA) SF and varying concentrations of either mLBP and/or IL-1ra. The catabolic activity of the SF and the relative effects of mLBP and/or IL-1ra were assessed by determining the percentage release of sulfated glycosaminoglycans from cartilage explants. LIF concentrations were measured by ELISA. RESULTS: RA SF but not OA SF stimulated release of proteoglycans from pig cartilage explants in vitro (47.3 +/- 2.2% vs 24.6 +/- 2.0%; p < 0.0001). Murine LBP at 100 ng/ml and recombinant human (rh) IL-1ra at 5000 ng/ml produced a dose dependent inhibition of this proteoglycan release (p < 0.0067 and p < 0.0111, respectively). The RA SF stimulated proteoglycan release was attenuated by mLBP and rhIL-1ra independently. No additive effect of this attenuation was observed when maximal inhibitory doses were used in combination. The decrease in proteoglycan release produced by mLBP correlated significantly with LIF concentrations in RA SF. CONCLUSION: These findings are consistent with the concept that IL-1 stimulates cartilage proteoglycan resorption in RA. They also support the hypothesis that LIF, too, contributes to cartilage proteoglycan resorption in RA. The residual stimulation not accounted for by IL-1 or LIF suggests other cytokines may contribute. The role of LIF and related or unrelated cytokines may need to be taken into account to optimize chondroprotection in RA and other rheumatic diseases.

Animals↗
PubMed1999

Oncostatin M induces leukocyte infiltration and cartilage proteoglycan degradation in vivo in goat joints.

OBJECTIVE: To evaluate the effect of intraarticular injections of recombinant human oncostatin M (rHuOSM) in the goat joint. METHODS: One milliliter of endotoxin-free normal saline (vehicle) containing either 40 ng, 200 ng, or 1,000 ng of rHuOSM was injected into the right radiocarpal joints (RCJs) of 12 male angora goats, while the left RCJs were injected with an equivalent volume of vehicle alone. In subsequent studies, the right and left RCJs of 8 male angora goats were injected with 200 ng of rHuOSM, and 1 hour later, the right RCJs were injected with either 5 microg of recombinant murine leukemia inhibitory factor binding protein (rMuLBP) or 1 mg of recombinant human interleukin-1 receptor antagonist (rHuIL-1Ra) in 1 ml of vehicle, while the left RCJs received 1 ml of vehicle alone. Goat joints were examined for clinical features of inflammation, and synovial fluid (SF) was aspirated on day 0 (before injection) and at days 2 and 6 postinjection. RESULTS: Injections of rHuOSM stimulated dose-dependent increases in the carpal:metacarpal ratio, SF volume, and SF leukocyte numbers, and stimulated dose-dependent decreases in the cartilage proteoglycan (PG) content ex vivo and PG synthesis. No significant changes were observed in the control joints that received saline alone, or between RCJs that were injected with 200 ng rHuOSM followed by 5 microg rMuLBP and RCJs that were injected with 200 ng of rHuOSM alone, except in respect to synovial fluid keratan sulfate concentrations, where a modest statistically significant reduction was observed in the joints injected with the combination of rHuOSM and rMuLPB. In contrast, RCJs injected with 200 ng rHuOSM followed by 1 mg of rHuIL-1Ra had significantly lower SF volumes (P<0.0001) and a significantly higher rate of ex vivo PG synthesis (P<0.0001). CONCLUSION: These results indicate that rHuOSM stimulates inflammation and modulates cartilage PG metabolism in vivo. Some of the effects of rHuOSM in vivo appear to be due, in part, to elaboration of IL-1. Even at very high doses, however, the rHuIL-1Ra did not attenuate OSM-mediated cartilage PG resorption. Thus, OSM has the potential to contribute to synovitis in vivo and can stimulate cartilage PG resorption in vivo, independent of IL-1.

Animals↗
PubMed1999

The proinflammatory and chondral activities of leukemia inhibitory factor in goat joints are partially a function of interleukin-1.

We wished to determine if the effects of injected recombinant human leukemia inhibitory factor (LIF) are a function of endogenous goat interleukin-1 (IL-1) production and, conversely, if the effects of injected recombinant human IL-1 are a function of endogenous LIF production in goat radiocarpal joints (RCJ). In preliminary experiments, murine LIF binding protein (MuLBP) and recombinant HuIL-1RA were found to independently attenuate the cartilage proteoglycan resorbing activity of goat synovial membrane-conditioned medium (GSMCM), implying activity against goat LIF and goat IL-1, respectively. The present study shows that the proinflammatory and chondral actions of rHuLIF in goat RCJ are partially attenuated by rHuIL-1RA. This implies that a small but important component of the in vivo activity of rHuLIF is a result of IL-1 production in the synovial joint. With the exception of proteoglycan synthesis, the absence of significant effects by MuLBP on the actions of rHuIL-1alpha in goat RCJ suggests that the proinflammatory and chondral effects of IL-1alpha in vivo are probably not mediated by LIF.

Animals↗
PubMed1999

Pelvic malignancy in female nonagenarians.

Reports about pelvic malignancy in female nonagenarians are scarce. Thirteen women 90 years of age and older were diagnosed with a malignant pelvic tumor between 1984 and 1996. The majority of these malignancies were gynecologic in origin. The development of a malignant pelvic tumor was, in our experience, associated with a poor prognosis. However, long-term cure after definitive treatment, as deemed feasible, is not precluded.

Adenocarcinoma↗
PubMed1998

Lymphocyte apoptosis induced by Fas ligand- expressing ovarian carcinoma cells. Implications for altered expression of T cell receptor in tumor-associated lymphocytes.

We have recently reported that tumor-associated lymphocytes obtained from ascitic fluids of women with ovarian carcinoma (OvCA) demonstrate a marked decrease in expression of cytoplasmic CD3-zeta and surface CD3-epsilon chains, which is associated with altered function of T cell receptor (TcR). We now demonstrate that OvCAs in situ and in culture express functional Fas ligand (FasL), capable of triggering an intrinsic cell death program in Fas-expressing T cells. The possibility of a relationship between cell death and altered expression of TcR was examined. The data indicate that alterations in expression of CD3-zeta and CD3-epsilon chains in T cells coincubated with OvCA are related to tumor-induced apoptosis, as the addition of pan-caspase inhibitors, DEVD-cho or YVAD-cho, prevents both the in vitro induction of T cell death by OvCA cells and the changes in the level of expression of CD3-zeta and CD3-epsilon chains. In the presence of Fas-Fc fusion protein, but not Fc-control protein, the loss in expression of CD3-zeta and CD3-epsilon chains induced in T cells by FasL+ OvCA cells was prevented. These results suggest that the loss in expression of CD3-zeta and CD3-epsilon chains in T lymphocytes interacting with OvCA cells is associated with apoptosis mediated by FasL-expressing tumor cells.

Adult↗
PubMed1998

Modulation of cartilage proteoglycan metabolism by LIF binding protein.

Leukaemia inhibitory factor (LIF) and oncostatin M (OSM) exhibit pleiotropic biological activities, share many structural and genetic features and bind with high affinity to the same receptor (LIF/OSM receptor). A soluble form of the LIF-R alpha, called LIF binding protein (LBP) has been isolated from mouse serum. LIF and OSM stimulate proteoglycan (PG) release and inhibit PG synthesis in cultured pig articular cartilage explants. The aim of this study was to determine whether LBP can block PG resorption and or reverse the inhibition of PG synthesis induced by LIF and OSM. In cultured pig cartilage explants LBP was found to dose dependently inhibit LIF stimulated release of PGs and reverse the suppression of PG synthesis. LBP was found to substantially attenuate the effects of LIF. In contrast only partial inhibition of the stimulatory effect of OSM was observed at the highest concentration of LBP available. At maximal concentrations, LBP produced minimal reversal of OSM mediated inhibition of PG synthesis. When tested in combination LIF and OSM had no additive effects on PG metabolism, but the combination of LIF and IL-1 and also OSM and IL-1 did show additive effects in respect to stimulation of PG catabolism and inhibition of PG synthesis. These effects were significantly greater than those observed for LIF, OSM and IL-1 alone. The results suggest that pig articular chondrocytes possess the LIF/OSM receptor, but possibly not an independent OSM receptor. The actions of mLBP indicate that rhLBP could be a clinically useful antagonist for LIF and perhaps OSM.

Animals↗
PubMed1998

Spinal epidural compression complicating cancer of the cervix: review of seven cases.

Records of women with newly diagnosed cancer of the cervix during a 16-year period were reviewed retrospectively for the development of spinal epidural compression by metastatic tumor (SECMT). Of the 361 cases studied, seven patients (2%) experienced SECMT. Epidural compression often involved the lumbar segment, tended to occur in the nonelderly population, and was relatively protracted in onset following the diagnosis of cervical cancer in cases of metachronous presentations. Although the prognosis was generally poor, the application of therapy may have promoted a better quality of remaining life by relieving pain or restoring the ability to walk.

Adult↗
PubMed1998

Brachytherapy in the presence of pyuria after pelvic irradiation for cervical cancer.

Little is known about the effects of intracavitary brachytherapy (ICB) performed in the presence of pyuria resulting from external beam pelvic irradiation for cervical cancer (CC). A retrospective study of one decade of ICB for CC showed that brachytherapy was performed in the presence of pyuria in 26 women. Twelve women without pyuria during ICB served as a control group. Antibiotic therapy was routinely administered during intracavitary application. The crude survival rate at 5 years was 39% in patients with pyuria and 42% in women without pyuria; the corresponding local recurrence rates were 23% and 17%; the serious complication rates were 12% and 0% respectively. Intracavitary brachytherapy in the presence of pyuria may have a limited adverse effect on the outcome of women with cancer of the cervix.

Adult↗
PubMed1997

Rectal immunization for induction of specific antibody in the genital tract of women.

The purpose of the current study was to examine potential routes of vaccine administration for the induction of antigen-specific responses in the genital tract of women. Sixteen women were enrolled in this study, and the level of influenza-specific antibodies induced in the genital tract was measured after rectal or intramuscular immunizations. Both methods of administration induced significant increases in the concentration of flu-specific IgA found in cervical secretions within 28 days after vaccination. Initially flu-specific IgG antibodies were not induced in the genital tract by either route. As expected both IgA and IgG flu-specific antibodies were dramatically increased in serum after intramuscular vaccination. In contrast, rectal administration did not induce significant IgA responses, and only small flu-specific IgG increases in serum. Six months after administration, IgA flu-specific antibody concentrations were significantly higher than baseline levels in vaginal secretions and saliva isolated from both subject groups and flu-specific IgG concentrations in cervical secretions were high in the rectal immunization group. The long-term presence of both IgG and IgA antibody in genital secretions suggests that rectal immunization may be an effective method for induction of immune protection in the genital tract of women.

Administration, Rectal↗