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S J Hawkyard

Publications and source records attributed to S J Hawkyard.

10 recordsLinked to original sources
PubMed2000

Mechanisms of action of intravesical bacille Calmette-Guérin: local immune mechanisms.

The local immune response to mycobacteria is complex, but mycobacterial antigen presentation by phagocytes to T helper cells is the pivotal interaction. Bacille Calmette-Guérin (BCG) vaccination is associated with the development of antituberculosis immunity but not necessarily with antitumor immunity. Animal studies have shown that an intact host immune system is required for the antitumor activity of BCG. Immunosuppressed and, particularly, T cell-depleted individuals fail to respond to BCG immunotherapy. Clinical and laboratory evidence suggest that the antitumor activity is concentrated at the site of BCG administration, which reinforces the view that local immune mechanisms are responsible for this phenomenon.

Administration, Intravesical↗
PubMed1995

The effect of extracorporeal piezoelectric lithotripsy on the contractility of the human pelvicalyceal system.

OBJECTIVE: To assess the effect of extracorporeal piezoelectric lithotripsy (EPL) on the contractility of the human pelvicalyceal system. PATIENTS AND METHODS: Contractions of the pelvicalyceal system were measured in 12 patients (mean age 55 years) before and after EPL. Pelvicalyceal pressure was measured via a Cope nephrostomy tube which had remained in situ following stone debulking procedures days or weeks earlier. All patients were treated using a Wolf Piezolith 2300 lithotripter. RESULTS: The pelvicalyceal systems of two patients were acontractile before and after treatment. Immediately after treatment, contractions were completely abolished in eight of the remaining 10 systems, and reduced in frequency in the other two. All 10 systems regained contractions 24 h after treatment. CONCLUSION: Piezoelectric lithotripsy temporarily abolishes upper urinary tract motility.

Female↗
PubMed1993

The immunomodulatory effects of urine from patients with superficial bladder cancer receiving intravesical evans BCG therapy.

Bladder cancer cells were stimulated with urine obtained from patients with superficial bladder cancer who had received treatment using intravesical bacillus Calmette-Guérin (BCG). The urine from the first 12 h following each of six BCG instillations was collected and examined for its biological effect. We evaluated effects that had previously been attributed to cytokines detected in the urine of such patients. The modulation of MHC class II antigen and intercellular adhesion molecule-1 (ICAM-1) expression were studied. Using neutralizing polyclonal antibodies to interferon gamma and tumour factor alpha the relative contribution of these molecules to the effects investigated were determined. When cells were stimulated for up to 48 h with first-instillation urine, little effect was seen in any of the parameters investigated. Urine from the sixth instillation, however, proved to be a potent immunomodulatory agent, inducing MHC class II molecule and ICAM-1 expression. Urine from instillations two to five mediated increasing immunomodulatory effects. When sixth-instillation urine samples were treated with neutralizing antibodies to interferon gamma prior to their addition to the bladder cancer cells, a marked and significant decrease in their potency was observed. Only in urine from one patient did any immunomodulatory capability remain after antibody treatment. Neutralizing antibodies to tumour necrosis factor alpha, however, failed to reduce the ability of any patient's urine to induce ICAM-1 expression. When both antibodies were used simultaneously no further decrease in potency was observed. These studies demonstrate for the first time the potential immunomodulatory and cytotoxic effects of urine produced by patients receiving intravesical BCG. Furthermore, in all samples tested, the major immunomodulatory component was shown to be interferon gamma. Although tumour necrosis factor alpha is produced as a result of BCG therapy, this cytokine did not appear to contribute to the parameters investigated, namely the induction of HLA class II antigens, and cell-surface ICAM-1.

BCG Vaccine↗
PubMed1993

The effect of recombinant cytokines on bladder cancer cells in vitro.

We have studied the Major Histocompatibility Class II-modulating and antiproliferative actions of recombinant interferon-gamma, tumor necrosis factor-alpha, interleukin-1 alpha, interleukin-2 and granulocyte macrophage-colony stimulating factor on bladder cancer cells in vitro. Indirect immunofluorescent staining employing monoclonal antibody probes in conjunction with flow cytometric analysis and tritiated thymidine incorporation assays were used. Interferon-gamma was a strong inducer and enhancer of class II antigens. Tumor necrosis factor-alpha could not induce the expression of class II antigens on tumor cells, which were initially class II-negative, but enhanced the expression on cells which already demonstrated low levels of the antigen. Interleukin-1, interleukin-2 and granulocyte macrophage-colony stimulating factor did not affect the major histocompatibility class II expression. Interferon-gamma and tumor necrosis factor-alpha both demonstrated powerful anti-proliferative effects on the bladder cancer cells, particularly those derived from low grade tumors (G1 and G2). Interleukin-1 alpha had no effect on tumor cell proliferation. In contrast interleukin-2 and granulocyte macrophage-colony stimulating factor had significant stimulatory effects on the proliferation of the low grade tumor cells (G1).

Antigens, Neoplasm↗
PubMed1992

Expression of interferon-gamma receptors on bladder cancer cells: does it correlate with biological response?

Previously we have shown a differential biological response of three human bladder cancer cell lines (RT4, RT112 and MGH-U1) to gamma interferon (IFN-gamma). The present study examines the relationship between the biological response and the expression of the interferon-gamma receptor on the tumour cell surface. Using a competitive radioligand binding assay and Scatchard analysis, we measured the number and affinity of the IFN-gamma receptors on each of the above cell lines. Individual cells from each line expressed large numbers (29,100-41,800) of high-affinity receptors (kd = 2.4-3.9 x 10(10) M). There was no statistically significant difference in either of these parameters between the three lines. We therefore conclude that the biological response of these bladder lines to IFN-gamma does not relate to the number or affinity of its receptor on the plasma membrane of these tumour cells.

Carcinoma, Transitional Cell↗
PubMed1992

An investigation of factors influencing the in vitro induction of LAK activity against a variety of human bladder cancer cell lines.

We investigated the sensitivity of transitional cell carcinoma cells, derived from the human bladder, to lymphokine activated killer cells. Recombinant interleukin-2 activated peripheral blood mononuclear cells were studied for their ability to mediate the cytolysis of a panel of four established human bladder transitional cell carcinoma cell lines. Lymphokine activated killer activity was assessed using a standard four hour chromium release assay. All four bladder cancer cell lines proved to be susceptible to lymphokine activated killer mediated cytolysis. This was found to be dependent upon the dose of cytokine and upon the duration of the activation period. The four cell lines were differentially susceptible to lysis (specific cytotoxicity at effector to target ratio of 40:1; RT112 = 22.9%, RT4 = 49.2%, MGH-U1 = 49.1%, EJ18 = 62.3%). The varying susceptibility of lymphokine activated killer mediated cytotoxicity was found to be independent of the histological grade of the parent tumour or the donor of effector cells. Both interferon-alpha and tumour necrosis factor-alpha also elicited lymphokine activated killer cell activity, although the maximum specific cytotoxicity achieved was considerably lower than that obtained with interleukin-2 alone. Interleukin-2, at optimal concentration, and tumour necrosis factor-alpha were found to behave synergistically in the generation of lymphokine activated killer effectors. However, concentrations of tumour necrosis factor-alpha higher than 100 Uml.-1 resulted in a decrease in specific cytotoxicity. These findings suggest a possible use of adoptive immunotherapy in human bladder cancer and indicate the optimum conditions for the generation of such effector cells.

Carcinoma, Transitional Cell↗
PubMed1992

The inhibitory effects of interferon gamma on the growth of bladder cancer cells.

The inhibitory effect of interferon-gamma on the growth of three human bladder cancer cell lines, RT4, RT112 and MGH-U1, representing tumour grades 1, 2 and 3 respectively, was studied. The effects of 10, 100 and 1000 Uml.-1 of interferon-gamma on cell numbers and thymidine incorporation were measured at 24 hour intervals up to a maximum of seven days. Morphological appearances were also studied. Each line was susceptible to the growth inhibitory effects of interferon-gamma and this was both dose and time dependent. The effects of interferon-gamma, on the RT4 and RT112 cells were apparent from 24 hours, and were both cytostatic and cytotoxic in nature, whereas the effects on MGH-U1 cells were seen from 48 hours onwards and were only cytostatic. Cytological changes occurred in all three cell lines, being most pronounced in RT112. The growth of bladder cancer cells was inhibited by interferon-gamma, and in this study high grade tumour cells were least sensitive.

Carcinoma, Transitional Cell↗
PubMed1992

Attenuating the hypertensive response to laryngoscopy and endotracheal intubation using awake fibreoptic intubation.

Blood pressure and pulse rate measurements were recorded in 35 patients undergoing endotracheal intubation during general anaesthesia (Group A), and 35 patients who had an awake fibreoptic intubation under local anaesthesia (Group B). The mean arterial pressure in Group A rose by a mean of 35 mmHg immediately after intubation, compared with a mean fall of 9 mmHg in Group B. The mean pulse rate in Group A rose by 24 beats per minute (b.p.m.) immediately after intubation, compared with a rise of 3 b.p.m. in Group B. Both these differences were statistically significant (P less than 0.0001 and P less than 0.001 respectively, Mann Whitney U test). Postoperative discomfort was assessed 24 h later by means of linear analogue scales. There was a statistically higher mean score in relation to nose discomfort in Group B (P less than 0.002). Awake fibreoptic intubation successfully reduces the pressor response to endotracheal intubation in normotensive adults. It is suitable for use in those patients who are at risk from the pressor response.

Anesthesia, General↗
PubMed1990

Cholecystostomy: a safe alternative?

We have studied retrospectively 27 patients undergoing cholecystostomy for acute cholecystitis over the past decade. The mean age of the patients was 60 years, and 17 were female. 'Difficult dissection' was the reason given for cholecystostomy in 18 cases and in the remainder the patients were deemed unfit for cholecystectomy. An operative cholangiogram was performed in only two cases, and none of the patients had a primary common bile duct exploration. Post-operative cholangiograms in 14 patients revealed common bile duct stones in three (21%). Three elderly patients (mean age 79) died in hospital. At a mean follow-up of one year, 26% of patients had come to elective cholecystectomy, and there had been a further three unrelated deaths. We conclude that under difficult circumstances, cholecystostomy may be a safe alternative to cholecystectomy. These patients have a high incidence of choledocholithiasis, and thus we would recommend operative cholangiograms in all patients. However, early ERCP and sphincterotomy may be a safe alternative if this service becomes more widely available.

Acute Disease↗