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Biomedical subjects

A Webb

Publications and source records attributed to A Webb.

At least 73 records · Page 4Linked to original sources
PubMed1999

Salmonella landau as a live vaccine against Escherichia coli O157:H7 investigated in a mouse model of intestinal colonization.

The present study was performed to assess the potential of a humoral mucosal immune response directed against the O157 antigen of Escherichia coli O157:H7 to prevent intestinal colonization by the pathogen. To this end, mice were gavaged with inocula of Salmonella landau, a Salmonella strain that naturally expresses the O157 antigen. Salmonella landau was avirulent for mice. Despite this, mice exposed to S. landau developed high titres of serum and coproantibodies against the O157 antigen. These mice, compared with controls, demonstrated some ability to resist transient intestinal colonization by an oral inoculum of an isolate of E. coli O157:H7. These findings suggest that a local immune response directed against the O157 antigen might increase host resistance to this pathogen.

Administration, Oral↗
PubMed1999

Imunosuppression by a corticosteroid fails to exacerbate Helicobacter pylori infection in a mouse model of gastric colonization.

Helicobacter pylori can colonize the human stomach for prolonged periods of time, and this colonization uniformly leads to the development of chronic active gastritis. In a small percentage of individuals, gastric pathology progresses to peptic ulceration or more rarely certain gastric cancers. In addition to non-specific inflammation, specific systemic and local immunity develops in response to gastric colonization by this pathogen. However, these responses combined appear inadequate for eliminating H. pylori from the gastric mucosa. This is also the case in a mouse model of gastric colonization by H. pylori. In the present study, we attempted to determine whether the mammalian host response to infection with H. pylori exerts any overt antibacterial effects. To this end we examined H. pylori colonization in normal mice, and mice immunosuppressed by treatment with a corticosteroid. Despite obvious suppression of the immune response in the latter mice, H. pylori burdens remained similar in both groups after three months of colonization. This suggests that the murine host response, at least, exerts little obvious protection against H. pylori colonization.

Animals↗
PubMed1998

Treatment algorithm use to optimize management of symptomatic patients with a history of mania.

BACKGROUND: While monotherapy has significant limitations in bipolar disorder, few published data addressing alternatives exist. Treatment algorithms have been proposed, but none have undergone empirical evaluation. This study provides a systematic prospective, open evaluation of the effectiveness and tolerability of a treatment algorithm for patients with histories of mania. METHOD: Twenty-eight symptomatic outpatients from a public mental health facility who were diagnosed as having either bipolar I or schizoaffective illness, bipolar type, entered the study. Minimum blood levels of lithium and divalproex sodium were defined. Medications were pushed to predetermined levels (as tolerated) before proceeding to the next algorithm step. Clinical symptoms were assessed monthly using the Brief Psychiatric Rating Scale (BPRS, 27 item) and Clinical Global Impressions scale. RESULTS: Pretreatment and posttreatment clinical symptoms were compared. Over 50% of patients attained 30% improvement from baseline BPRS after 4 months. Thirty-six percent of patients (N = 10) became mood stable, 46% (N = 13) remained mood unstable, and 18% (N = 5) dropped out before completing the algorithm. Although patients who finished the algorithm were taking more medication, either dosage and/or drugs, somatic complaints did not increase. CONCLUSION: The potential benefit of a defined treatment algorithm was demonstrated for these complex and persistently ill patients. Despite long treatment histories, patients improved with more frequent visits and addition of medication(s). A randomized controlled trial comparing a similar treatment algorithm with treatment-as-usual is warranted.

Adult↗
PubMed1998

What's in a name.

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Family Planning Services↗
PubMed1997

BCL-2 antisense therapy in patients with non-Hodgkin lymphoma.

BACKGROUND: Overexpression of BCL-2 is common in non-Hodgkin lymphoma and leads to resistance to programmed cell death (apoptosis) and promotes tumorigenesis. Antisense oligonucleotides targeted at the open reading frame of the BCL-2 mRNA cause a specific down-regulation of BCL-2 expression which leads to increased apoptosis. Lymphoma grown in laboratory animals responds to BCL-2 antisense oligonucleotides with few toxic effects. We report the first study of BCL-2 antisense therapy in human beings. METHODS: A daily subcutaneous infusion of 18-base, fully phosporothioated antisense oligonucleotide was administered for 2 weeks to nine patients who had BCL-2-positive relapsed non-Hodgkin lymphoma. Toxicity was scored by the common toxicity criteria, and tumour response was assessed by computed tomography scan. Efficacy was also assessed by quantification of BCL-2 expression; BCL-2 protein levels were measured by flow cytometry in samples from patients. FINDINGS: During the course of the study, the daily dose of BCL-2 antisense was increased incrementally from 4.6 mg/m2 to 73.6 mg/m2. No treatment-related toxic effects occurred, apart from local inflammation at the infusion site. In two patients, computed tomography scans showed a reduction in tumour size (one minor, one complete response). In two patients, the number of circulating lymphoma cells decreased during treatment. In four patients, serum concentrations of lactate dehydrogenase fell, and in two of these patients symptoms improved. We were able to measure BCL-2 levels by flow cytometry in the samples of five patients, two of whom had reduced levels of BCL-2 protein. INTERPRETATION: In patients with relapsing non-Hodgkin lymphoma, BCL-2 antisense therapy led to an improvement in symptoms, objective biochemical and radiological evidence of tumour response, and down-regulation of the BCL-2 protein in some patients. Our findings are encouraging and warrant further investigations of BCL-2 antisense therapy in cancer treatment.

Adult↗
PubMed1997

Concentrations of mercury in otters (Lutra lutra L.) in Scotland in relation to rainfall.

Concentrations of mercury (Hg) were measured in 112 livers of otters from various areas in Scotland during 1986-1992. Mercury concentration varied from 0.3-44.7 ppm (dry). There was a significant positive correlation between Hg in otters and annual rainfall, consistent with an atmospheric origin of mercury pollution. Mercury concentration was higher in animals with lower body condition. Concentrations were shown to increase with the age of the animal, but not everywhere, and the correlation was weak. It appeared unlikely that during the study period otter numbers were affected by mercury.

Journal Article↗
PubMed1997

A prospective analysis of 949 long-term central venous access catheters for ambulatory chemotherapy in patients with gastrointestinal malignancy.

We present a prospective analysis of the insertion complications and longevity of 949 cuffed, tunnelled central venous catheters used for ambulatory chemotherapy. Mean catheter life span was 121.8 days, 13.4% had complications at insertion, 17.7% had complications not necessitating removal and 18.6% had complications requiring removal. The more experienced operators had fewer complications inserting catheters (P < 0.0001). Late-onset shoulder pain occurred in 4.8% and was associated with an increased incidence of venous thrombosis (P < 0.0001) and infection (P = 0.06). Complications necessitating removal were not predicted by patient' age, site of insertion or malignancy, chemotherapy regimen, insertion platelet and fibrinogen counts, insertion complications, leucocyte count or cuff distance from the exist site. Catheters inserted with their tip in the superior vena cava were more at risk of removal (2.57 times) than those in the right atrium (P = 0.003).

Adolescent↗
PubMed1997

A prospective randomised trial of protracted venous infusion 5-fluorouracil with or without mitomycin C in advanced colorectal cancer.

BACKGROUND: To compare protracted venous infusion (PVI) 5-fluorouracil (5-FU) with and without mitomycin C (MMC) in a prospectively randomised study and analyse for tumour response, survival, toxicity and quality of life (QL). PATIENTS AND METHODS: Two hundred patients with advanced colorectal cancer received PVI 5-FU 300 mg/m2/day for a maximum of 24 weeks and were randomised to PVI 5-FU alone or PVI 5-FU + MMC 10 mg/m2 (7 mg/m2 from June 1995) 6 weekly for 4 courses. RESULTS: Overall response was 54% (95% confidence interval [CI] 44.1%-63.9%) with PVI 5-FU + MMC compared to 38% (95% CI: 28.3%-47.7%) for PVI 5-FU alone (P = 0.024). The median failure free survival was 7.9 months in PVI 5-FU plus MMC and 5.4 months with PVI 5-FU alone (P = 0.033) and at one year 31.9% for the combination compared to 17.7% for PVI 5-FU alone. Median survival was 14 months with MMC and 15 months in 5-FU alone; one-year survival 51.7% vs. 57.2%. PVI 5-FU + MMC caused more overall haematological toxicity but CTC grades 3/4 was increased only for thrombocytopaenia. Two patients treated with a cumulative dose of MMC of 40 mg/m2 developed haemolytic uraemic syndrome warranting the reduction in cumulative MMC dose to 28 mg/m2. The global QL scores were better for PVI 5-FU + MMC arm at 24 weeks, but the remaining QL data showed no differences. CONCLUSIONS: PVI 5-FU + MMC results in failure-free survival and response advantage, tolerable toxicity and better QL when compared to PVI 5-FU alone but no overall survival advantage. There is no irreversible toxicity with MMC at a cumulative dose of 28 mg/m2.

Adenocarcinoma↗
PubMed1997

Glial lineages and myelination in the central nervous system.

Oligodendrocytes, derived from stem cell precursors which arise in subventricular zones of the developing central nervous system, have as their specialist role the synthesis and maintenance of myelin. Astrocytes contribute to the cellular architecture of the central nervous system and act as a source of growth factors and cytokines; microglia are bone-marrow derived macrophages which function as primary immunocompetent cells in the central nervous system. Myelination depends on the establishment of stable relationships between each differentiated oligodendrocyte and short segments of several neighbouring axons. There is growing evidence, especially from studies of glial cell implantation, that oligodendrocyte precursors persist in the adult nervous system and provide a limited capacity for the restoration of structure and function in myelinated pathways damaged by injury or disease.

Adult↗
PubMed1997

Randomized trial comparing epirubicin, cisplatin, and fluorouracil versus fluorouracil, doxorubicin, and methotrexate in advanced esophagogastric cancer.

PURPOSE: We report the results of a prospectively randomized study that compared the combination of epirubicin, cisplatin, and protracted venous infusion fluorouracil (5-FU) (ECF regimen) with the standard combination of 5-FU, doxorubicin, and methotrexate (FAMTX) in previously untreated patients with advanced esophagogastric cancer. PATIENTS AND METHODS: Two hundred seventy-four patients with adenocarcinoma or undifferentiated carcinoma were randomized and analyzed for survival, tumor response, toxicity, and quality of life (QL). RESULTS: The overall response rate was 45% (95% confidence interval [CI], 36% to 54%) with ECF and 21% (95% CI, 13% to 29%) with FAMTX (P = .0002). Toxicity was tolerable and there were only three toxic deaths. The FAMTX regimen caused more hematologic toxicity and serious infections, but ECF caused more emesis and alopecia. The median survival duration was 8.9 months with ECF and 5.7 months with FAMTX (P = .0009); at 1 year, 36% (95% CI, 27% to 45%) of ECF and 21% (95% CI, 14% to 29%) of FAMTX patients were alive. The median failure-free survival duration was 7.4 months with ECF and 3.4 months with FAMTX (P = .00006). The global QL scores were better for ECF at 24 weeks, but the remaining QL data showed no differences between either arm of the study. Hospital-based cost analysis on a subset of patients was similar for each arm and translated into an increment cost of $975 per life-year gained. CONCLUSION: The ECF regimen results in a survival and response advantage, tolerable toxicity, better QL and cost-effectiveness compared with FAMTX chemotherapy. This regimen should now be considered the standard treatment for advanced esophagogastric cancer.

Adenocarcinoma↗
PubMed1996

Is postictal electrical silence a predictor of response to electroconvulsive therapy?

Electroconvulsive therapy (ECT) is an established effective treatment modality for patients with severe depression. Recent studies have focused on developing predictors of response. In this prospective study, using percent decrease in Hamilton Depression Scale (21 items) as the outcome measure, we blindly evaluated 33 inpatients with major depression to determine whether postictal suppression, the electrical silence following induced seizure, would predict treatment response to ECT. A significant relationship was observed between degree of postictal suppression and likelihood of clinical improvement. Postictal suppression should be explored in more controlled studies as a predictor of ECT response.

Brain↗
PubMed1996

Epirubicin, cisplatin, and protracted venous infusion of 5-fluorouracil for esophagogastric adenocarcinoma: response, toxicity, quality of life, and survival.

BACKGROUND: The results of chemotherapy for patients with esophagogastric carcinoma have generally been modest but regimens developed more recently have produced higher response rates, and rekindled interest in neoadjuvant chemotherapy. One such regimen is epirubicin, cisplatin, and 5-fluorouracil (ECF). This study evaluates its efficacy, toxicity, impact on quality of life (QL), and impact on survival in a large consecutive series of patients with metastatic and locally advanced disease (LAD). METHODS: Patients with histologically confirmed esophagogastric carcinoma were treated with ECF (epirubicin 50 mg/m2 and cisplatin 60 mg/m2 every 3 weeks with continuous infusion of 5-fluorouracil (5-FU) 200 mg/m2/d). Responses were evaluated with computed tomography (CT) scan and endoscopy. QL was assessed using the European Organization for Research and Treatment of Cancer QLQ-C30 questionnaire. RESULTS: A total of 235 patients were treated, 173 with metastatic disease and 62 with LAD. The mean number of cycles delivered was 6 (range: 1-11) and patients were followed-up for a median of 8 months. Response was observed in 135 of 220 (61%) evaluable patients, with a complete response (C(R)), 11% of the patients and a partial response in 50% of the patients. Patients with moderately differentiated adenocarcinomas and LAD responded most favorably. Symptomatic improvement was achieved in the majority of cases (63-78% depending on the symptom). Toxicity was generally only mild to moderate, with severe non hematologic toxicity in less than 12% of the patients and only 6 (2.5%) treatment related deaths. QL assessment showed no significant negative impact on emotional functioning and good symptomatic control. Surgery following response to ECF was performed in 29 of the LAD patients, and in 19 cases (66%) a potentially curative resection was possible, with histologic CR in 32% of the patients. CONCLUSIONS: ECF is a highly active regimen with acceptable toxicity in patients with esophagogastric adenocarcinoma. In a proportion of patients with LAD, chemotherapy enabled potentially curative surgery to be performed. The results justify further investigation of this regimen in a neoadjuvant setting.

Adenocarcinoma↗
PubMed1996

The prognostic value of serum and immunohistochemical tumour markers in advanced gastric cancer.

Using a prospectively acquired database of 290 patients with advanced gastric adenocarcinoma, the prognostic significance of serum levels of carcinoembryonic antigen (CEA) (237 patients), alphafeto protein (AFP) (164 patients), beta-human chorionic gonadotrophin (beta HCG) (165 patients), CA19-9 (64 patients) and CA125 (104 patients) and tissue staining for C-erb B-2 (160 patients) and beta HCG (160 patients) was investigated. Serum was taken prior to 5-fluorouracil (5FU)-based chemotherapy and immunohistochemistry was performed on diagnostic specimens. In the univariate analysis, tumour markers of poor prognosis were CEA > or = 5 micrograms/l (P = 0.01; median survival (MS) 42 versus 35 weeks), serum beta HCG > or = 4 U/l (P = 0.02; MS 42 versus 25 weeks), CA125 > or = 35 U/ml (P = 0.03; MS 43 versus 31 weeks) and CA125 > or = 350 U/ml (P = 0.001; MS 42 versus 17 weeks). Other significant factors were poor performance status, the presence of metastases and poorly differentiated tumour histology. Tumours markers of poor prognosis in the multivariate analysis were serum beta HCG > or = 4 IU/l [hazard ratio (HR) 1.7; 95% confidence interval (CI) 2.8-1.1] and CA125 > or = 350 U/ml (HR 2.2; CI 4.2-1.2). There was a degree of subgroup variability in this model but, in general, other factors correlating with a poor survival were poor performance status, metastases and poorly differentiated tumour histology. This is the largest prognostic study of each tumour marker in advanced disease and demonstrates that serum beta HCG and CA125 in gastric cancer prior to chemotherapy do convey an independent poor prognosis which may reflect not just tumour burden but aggressive biology.

Adenocarcinoma↗
PubMed1996

Unknown primary carcinoma: randomised studies are needed to identify optimal treatments and their benefits.

This is a retrospective review of 101 patients with unknown primary carcinoma (UPC) treated between 1989 and 1994, on whom data were collected prospectively. 92 patients received platinum-based chemotherapy and 9 had single agent 5-fluorouracil (5-FU). In the platinum group, an objective response rate of 37.2% was seen, with a median duration of 4.5 months (range 1.9-17.5). There were no responses with 5-FU alone, while median survival was 6.4 months and was not different from the platinum group (P = 0.09). Considerable symptomatic resolution was noted, although the contribution of chemotherapy alone to this is difficult to define. The impact of tumour response on quality of life and survival in UPC requires further elucidation in prospective studies with a "best supportive care' arm. The superiority of platinum-based treatments reported in selected subgroups cannot be applied to the whole spectrum of UPC.

Adenocarcinoma↗