Search PubMed⌕ Search

Biomedical subjects

N W Clarke

Publications and source records attributed to N W Clarke.

At least 37 records · Page 2Linked to original sources
PubMed2001

Interactions of human prostatic epithelial cells with bone marrow endothelium: binding and invasion.

Prostate cancer shows a propensity to form secondary tumours within the bone marrow. Such tumours are the major cause of mortality in this disease. We have developed an in vitro system to study the binding of prostate epithelial cells to bone marrow endothelium (BME) and stroma (BMS). The metastatic prostate cancer cell line, PC3 (derived from a bone metastasis), was seeded onto confluent layers of BME and its binding characteristics compared to human umbilical vein endothelial cells (HUVEC), lung endothelium (Hs888Lu) and BMS. The PC3 cell line showed significantly increased binding to BME (P< 0.05) compared to endothelium derived from HUVEC and lung or BMS with maximal binding occurring at 1 h. Following pre-incubation with a beta1 integrin antibody PC3 binding to BME was inhibited by 64% (P< 0.001). Antibodies directed against the integrins beta4, alpha2, alpha4, alpha5 and the cellular adhesion molecules P-selectin, CD31, VCAM-1 and sialy Lewis X showed no effect on blocking PC3 binding. Primary prostatic epithelial cells from both malignant (n = 11) and non-malignant tissue (n = 11) also demonstrated equivalent levels of increased adhesion to BME and BMS compared to HUVEC, peaking at 24 h. Further studies examined the invasive ability of prostate epithelial cells in response to bone marrow endothelium using Matrigel invasion chamber assays. In contrast to the previous results, malignant cells showed an increase (1000 fold) in invasive ability, whilst non-malignant prostate epithelia did not respond. We have shown that both malignant and non-malignant prostate epithelial cells can bind at equivalent levels and preferentially to primary human bone marrow endothelium in comparison to controls. However, only malignant prostate epithelia show increased invasive ability in response to BME.

Adenocarcinoma↗
PubMed2001

Molecular prediction of progression in patients with conservatively managed prostate cancer.

OBJECTIVES: To report our results with the use of reverse transcriptase-polymerase chain reaction (RT-PCR) as a potential predictor of prostate cancer (CaP) progression in patients managed with watchful waiting. There has been much recent debate about the safety of treating older patients with localized CaP with watchful waiting. The RT-PCR is an assay that can detect small numbers of prostate cells in circulating blood. METHODS: Blood samples were taken from male and female control patients and from patients with advanced, hormone-treated and untreated localized (watchful-waiting) CaP. Sensitive nested RT-PCR assays were carried out on these samples using primers for both prostate-specific antigen (PSA) and prostate-specific membrane antigen mRNA. RESULTS: Fifty-one blood samples were taken from patients managed with watchful waiting. Fourteen of these had positive RT-PCR results. These patients had a significantly higher PSA velocity than did the patients with negative RT-PCR results. Circulating prostate cells were detected in 18 of 24 patients with advanced CaP, 2 of 34 patients with stable, hormone-treated CaP, and in none of the negative controls. The assay was able to detect 20 LNCaP cells reliably when added to a 5-mL volunteer blood sample. CONCLUSIONS: A significant minority (27%) of patients with untreated localized CaP had detectable circulating prostate cells, and these patients tended to have a progressively rising serum PSA level. Despite low-grade disease and sometimes low serum PSA values, these patients may be at risk of early metastatic progression. RT-PCR, in conjunction with existing prognostic tests, may be of use in predicting which "watchful-waiting" patients are at risk of early progression.

Aged↗
PubMed2001

Ki-67 index in metastatic prostate cancer.

OBJECTIVE: Prostate cancer in bone is generally thought to progress more rapidly than in its primary site, a supposition that is supported by studies of prostate-specific antigen velocity. However, descriptions of proliferative rates in metastases have relied on inferred data from in vitro studies of cell lines derived from metastases. The aim of this study was to determine directly the proliferative rate within bone metastases arising from prostate cancer. PATIENTS AND METHODS: 10 bone biopsies containing metastatic deposits of untreated prostatic cancer were obtained. These were immunohistochemically stained for the Ki-67 protein with the monoclonal antibody MIB-1, using the streptavidin-biotin complex technique. Benign prostatic tissue was used as the control. Using an image analyser, the Ki-67 index (% of cells staining positively) in each specimen was determined. RESULTS: In the 10 specimens the Ki-67 index ranged from 0.15 to 7.82%. Wide overlap was seen between groups of differing tumour differentiation. CONCLUSION: The proliferative rate as determined by the Ki-67 index in bone metastases of prostate cancer is similar to that reported in primary tumours. There does not appear to be a relationship between tumour grade and proliferative index in these specimens.

Adenocarcinoma↗
PubMed2001

Photodynamic therapy for superficial bladder cancer.

In photodynamic therapy, a photosensitizing drug is activated by visible light and in the presence of oxygen, results in local cell death. This evolving modality is now being used to treat and palliate a very wide variety of human solid tumors and carcinoma-in-situ lesions. With regard to bladder cancer, advances in drug development and modern light delivery techniques mean that photodynamic therapy shows promise in the treatment of superficial bladder cancer resistant to conventional treatments.

Aminolevulinic Acid↗
PubMed2000

The staged management of complex entero-urinary fistulae.

OBJECTIVE: To present the results of the staged management of complex entero-urinary fistulae. PATIENTS AND METHODS: Ten patients with complex entero-urinary fistulae were reviewed; all patients were referred to a national intestinal failure unit after failed treatment in other centres. Each patient was treated in three stages. The acute stage involved proximal defunctioning and distal drainage of both the gastrointestinal and urinary tracts to isolate the fistula, together with the eradication of sepsis. The recovery stage involved total parenteral nutrition, organ support, radiological planning of surgical reconstruction and intensive nursing. The reconstructive stage followed when the patient was stable, nutritionally replenished and intra-abdominal sepsis was controlled. Surgery was undertaken jointly by urological and gastrointestinal surgeons. RESULTS: The fistulae were treated successfully in all patients, with functional restoration in four, and/or diversion of the gastrointestinal and urological tracts in six. The mean (range) time to reconstruction was 5 (1-20) months. There were no postoperative deaths. CONCLUSION: A staged multidisciplinary approach with delayed reconstruction can achieve a successful outcome in the management of complex entero-urinary fistulae.

Adult↗
PubMed2000

Light penetration in bladder tissue: implications for the intravesical photodynamic therapy of bladder tumours.

OBJECTIVES: To assess (i) the optical properties and depth of penetration of varying wavelengths of light in ex-vivo human bladder tissue, using specimens of normal bladder wall, transitional cell carcinoma (TCC) and bladder tissue after exposure to ionizing radiation; and (ii) to estimate the depth of bladder wall containing cancer that could potentially be treated with intravesical photodynamic therapy (PDT), assuming satisfactory tissue levels of photosensitizer. Materials and methods The study included 11 cystectomy specimens containing invasive TCC (five from patients who had previously received external-beam bladder radiotherapy, but with recurrent TCC) and three 'normal' bladders removed from patients treated by exenteration surgery for extravesical pelvic cancer. Full-thickness bladder wall and tumour samples were taken from these specimens and using an 'intravesical' and a previously validated interstitial model, the optical penetration depths (i.e. the tissue depth at which the light fluence is 37% of incident) were calculated at wavelengths of 633, 673 and 693 nm. RESULTS: There were no significant differences in light penetration between normal and tumour-affected bladder tissue at each wavelength. There were significant differences in light penetration among wavelengths; light at 693 nm penetrated approximately 40% further than light at 633 nm (P < 0.002). The light currently used in bladder PDT (633 nm) has a mean (SEM) optical penetration depth of 4.0 (0.1) mm within TCC. In addition, at this wavelength, there was 29% greater light penetration in previously irradiated than in unirradiated bladder wall (P = 0.001). This did not occur in the tumour-affected bladder. CONCLUSIONS: Bladder tissue is relatively more translucent than other human tissues and there is therefore great potential for PDT in the treatment of bladder cancer. As there is no difference in light penetration between TCC and normal bladder tissue, a tumour-specific response with diffuse illumination of the bladder will depend on drug localization within the tumour. The currently used wavelength of 633 nm can be expected to exert a PDT effect within bladder tumour up to a depth of 20 mm. Increasing the wavelength will allow deeper pathology to be treated.

Humans↗
PubMed2000

The post-cystectomy pseudotumour sign: MRI appearances of a modified chronic pelvic haematoma due to retained haemostatic gauze.

The magnetic resonance imaging (MRI) findings of five men who had incidental similar pelvic masses identified after radical cystectomy are presented. In all patients the haemostatic agent Kaltostat had been used. In one patient, surgical resection of the mass was performed and histological evaluation showed a foreign body inflammatory reaction within a chronic haematoma. The differentiation between this lesion and other post-operative collections or tumours is discussed.

Aged↗
PubMed2000

Optimization of the reverse transcriptase polymerase chain reaction for the detection of circulating prostate cells.

The reverse transcriptase polymerase chain reaction (RT-PCR) is a sensitive technique that can detect prostate-specific messenger RNA in circulating blood. Many authors have studied the potential of RT-PCR as a staging technique in prostate cancer (PC). Clinical sensitivity and in some cases specificity has been disappointing. Few authors have been able to correlate RT-PCR result with patient stage. We have compared the results of using two different RT-PCR protocols with different sensitivities on blood samples from prostate cancer patients. An 80-amplification-cycle nested primer RT-PCR assay had a detection limit of 10 prostate cells and a 50-cycle RT-PCR could detect 20 cells in 5 ml blood. The 80-cycle assay detected prostate mRNA in four of 10 female samples, whereas the 50-cycle assay detected it in none. There was little difference in the assays' ability to detect prostate mRNA in advanced PC patients. The 50-cycle assay could differentiate between hormone-escaped, stable hormone-treated and untreated localized PC patients, whereas the 80-cycle assay could not. Each blood sample must be assayed several times with RT-PCR to avoid false-negative results and, if this is done, assay specificity can be increased with little effect on clinical sensitivity.

False Negative Reactions↗
PubMed1999

Scatter factor influences the formation of prostate epithelial cell colonies on bone marrow stroma in vitro.

Prostate cancer metastases form selectively in the bone marrow. Previously we demonstrated motility was important for the formation of primary prostatic epithelial cell colonies in bone marrow stroma (BMS) co-culture. In this study we looked at the influence of motility factors on the colony formation of epithelial cells derived from benign (bPEC) or malignant (mPEC) prostate tissue. After 7 days co-culture we found that anti-scatter factor consistently inhibited prostate epithelial cell colony formation on BMS (7/7 mPEC and 4/7 bPEC samples showed significant inhibition). Antibodies against bFGF and 5T4 did not significantly affect colony formation. Addition of fibroblast conditioned media (derived from benign prostates) to co-cultures stimulated the colony formation of bPEC (170%) and mPEC (252%). This stimulation was eliminated by depletion of SF from the conditioned media. Immunohistochemical staining found c-Met expression in 5/6 bPEC cultures and 7/9 mPEC cultures. When grown in BMS co-culture expression of c-Met was positive in 3/6 bPEC and 2/7 mPEC samples. In conclusion, scatter factor influences the in vitro formation of prostate epithelial cell colonies on BMS co-culture.

Bone Marrow Cells↗
PubMed1999

Paradoxical expression of E-cadherin in prostatic bone metastases.

OBJECTIVE: To determine whether the calcium-dependent cell adhesion molecule E-cadherin is expressed in metastatic deposits of prostate cancer in bone. PATIENTS AND METHODS: Ten bone biopsies containing metastatic deposits of untreated prostatic cancer were obtained and immunohistochemically stained for E-cadherin with the monoclonal antibody HECD-1, using the streptavidin-biotin complex technique. Benign prostatic tissue was used as the control. RESULTS: Of the 10 specimens, nine showed positive expression of E-cadherin, graded as strong in four. E-cadherin expression was strongest in well-differentiated metastases and decreased with increasing tumour grade. In some specimens there were mixed patterns of expression. CONCLUSION: E-cadherin is strongly expressed in prostatic bone metastases and the degree of expression appears to reflect local tumour grade. This suggests that loss of E-cadherin expression may not be critically linked to metastatic potential.

Biopsy↗
PubMed1998

Interaction of prostate epithelial cells from benign and malignant tumor tissue with bone-marrow stroma.

BACKGROUND: Metastases of prostate cancer form selectively within the skeleton. To understand this metastatic spread, we studied the ability of prostate epithelial cells to grow and proliferate within the bone marrow, using primary coculture. METHODS: Prostate epithelia and fibroblasts were prepared from men with benign prostatic hyperplasia (n = 13) and cancer of the prostate (n = 10). Confluent cultures of bone-marrow stroma or fibroblast controls were prepared in 96-well plates, and identical plates were treated with detergent to expose the extracellular matrix of the cells. Epithelial cells were seeded onto either cells or matrix, and their growth characteristics were determined by counting increases in colony size and number over time. Further experiments evaluated the effects on epithelial growth when cells were exposed to media conditioned by these stroma, using an MTT assay. RESULTS: Results showed that for epithelial cells derived from malignant (or benign) tissue, the median value of the total area of colonies formed on bone-marrow stroma was 2.1 (benign, 2.6) mm2, in contrast to 0.3 (benign, 0.4) mm2 or 0.25 (benign, 0) mm2 when these cells were cocultured with fibroblasts from benign or malignant prostates, respectively. Statistics indicated that growth was significantly greater on bone-marrow stroma than on control stroma (P < 0.005). However, no significant stimulation of epithelial cell growth was seen when these epithelial cells were cultured on extracellular matrix from bone-marrow stroma or when exposed to bone-marrow stroma-conditioned media in comparison to fibroblast controls. No statistical differences were found between the formation of colonies from malignant tissue in comparison to benign. CONCLUSIONS: This system allows the investigation of bone-marrow stroma colonization by primary prostate epithelial cells, and could be developed for the study of metastasis.

Bone Marrow Cells↗
PubMed1997

Primary prostatic epithelial cell binding to human bone marrow stroma and the role of alpha2beta1 integrin.

Prostate cancer selectively metastasises to the bone. To investigate the importance of prostate epithelial cell adhesion to bone marrow cells in this process we examined the binding of human primary prostatic epithelial cells (PEC) to human bone marrow stromal cultures (BMS). We found that PEC derived from both malignant and benign tissue showed greater adhesion to BMS than to benign prostatic fibroblasts (median difference was 340% and 200% respectively), skin fibroblasts or plastic tissue culture plates. Adhesion to BMS grown from the bone marrow of patients with prostatic skeletal metastases was no different from those grown from normal bone marrow. The role of integrin molecules in these cell interactions was determined. Collagen type I and fibronectin were found to increase PEC adhesion whereas vitronectin and laminin did not. Inhibition studies demonstrated that although there was heterogeneity between samples, antibodies against the integrins alpha2 and beta1 consistently inhibited PEC binding to BMS. This result was more marked for PEC derived from malignant tissue. However studies investigating the effects of disintegrins and anti-alpha3 and anti-alpha5 integrins indicated that for a percentage of patients these integrins and RGD (arginine, glycine, aspartamine)-dependent binding pathways were also involved. In summary, the results indicate that BMS are adherent to primary PEC derived from both malignant and benign tissue. The integrin alpha2beta1 is a major contributor to this interaction.

Animals↗
PubMed1995

Urinary tract obstruction and nephrostomy drainage in pelvic malignant disease.

OBJECTIVE: To determine the survival of patients after percutaneous nephrostomy drainage (PND) for obstructive uropathy secondary to pelvic malignant disease. PATIENTS AND METHODS: The records of 77 patients undergoing PND for obstructive uropathy were reviewed. Patients were classified according to the nature of the obstructing lesion: Group I (primary untreated malignancy, 31 patients); Group II (recurrent malignancy with further treatment, 15 patients); Group III (recurrent malignancy with no further treatment, 12 patients); and Group IV (benign disease as a consequence of previous treatment, 19 patients). Outcome was assessed by survival over a mean follow-up of 20 months (range 2 days-8.3 years). RESULTS: Overall median survival was 26 weeks, with a 5-year survival of 22%. The survival in Groups I and II was not significantly different (median survival 27 and 20 weeks, respectively; 5-year survival, 10% and 20%, respectively). Group III patients had a poor prognosis (median survival 6.5 weeks) with no patient surviving beyond one year, whilst Group IV patients fared best with a 5-year survival of 64%. The commonest primary tumour type was carcinoma of the cervix (42 patients), and these patients were analysed as a subset. Benign post-radiation fibrosis was found in 16 of 27 patients (59%). Survival was related to the diagnostic group. CONCLUSION: The nature and extent of the obstructing lesion and its potential for further treatment are the major determinants of post-nephrostomy survival. Every effort should therefore be made to identify the nature of the obstruction before deciding on PND.

Adult↗
PubMed1994

Altered saccharide sequences in two groups of patients with metastatic prostatic carcinoma.

OBJECTIVE: To investigate the hypothesis that primary prostatic carcinomas with metastases to different sites (lymph nodes or bone) show varying expression of cell surface and cytoplasmic glycoconjugates. PATIENTS AND METHODS: A group of 14 patients with primary prostatic carcinoma with lymph node metastases but no bone metastases has previously been shown to have an increased survival time. This group was compared with a control group of 14 patients with lymph node-negative, bone metastasis-positive primary prostatic carcinoma using a panel of biotinylated lectins revealed by the avidin-biotin peroxidase complex method. The results were analysed semi-quantitatively and differences in binding patterns between the two groups were sought. RESULTS: No significant differences were seen using the LCA, LTA, UEA-1, WFA, VVA or SBA lectins. The group with bone metastases but no lymph node involvement showed significantly increased binding for the ECA and AHA lectins, both before and after neuraminidase pre-treatment, compared with the lymph node-positive group. CONCLUSIONS: These results suggest that tumours lacking or having a reduced affinity for binding sites for both Gal beta 1-3GalNac (Type I oligosaccharide structures--AHA) and Gal beta 1-4GlcNac (Type II oligosaccharide structures--ECA) sequences are more likely to develop lymph node metastases and less likely to develop bone metastases and thereby increasing the patient's chances of survival. This is further evidence that the metastatic potential of tumours per se and the ultimate site of distal metastases from such tumours is affected in part by the glycoconjugates expressed on their cell surfaces and indicates that metastatic phenotypes for prostatic carcinoma exists.

Aged↗