Delivery of multipotent adult progenitor cells via a functionalized plasma polymerized surface accelerates healing of murine diabetic wounds

Introduction: Stem cell therapies have been investigated as potential treatment modalities for chronic wounds however there has been limited success to date. Multipotent Adult Progenitor Cells (MAPCs©) have been identified as having potential as an allogenic stem cell product due to their high population doubling number and their characteristic dampening of T-cell proliferation. This helps to prevent autoimmunity and graft/cell rejection. Methods: We have developed a dressing, consisting of medical grade silicone coated with a heptylamine plasma polymer, which supports the growth and transfer of MAPCs to skin. To determine if the dressing can deliver functional stem cells into diabetic wounds, they were loaded with MAPCs and then placed over excisional wounds in both normal and diabetic mice. Results and discussion: Accelerated healing was observed in both the normal and diabetic wounds with wound gape being significantly smaller at day 3 when compared to controls. Wound analysis showed that treatment with the MAPC dressings dampened the inflammatory response with reduced numbers of neutrophils and macrophages observed. Additionally, an increase in pro-angiogenic VEGF and CD31 positive endothelial cells was observed indicating improved new blood vessel formation. The MAPC dressings had no effect on fibrosis with collagen I and III being equally affected in both control and treated wounds. Overall, the functionalized MAPC dressings improve healing responses particularly in diabetic mice with impaired healing responses and therefore, show potential for development as an advanced therapeutic approach for the treatment of chronic diabetic wounds.

Colorectal cancer care in the COVID-19 era: outcomes from a 'mixed site' model

INTRODUCTION

The COVID-19 pandemic has presented many challenges to colorectal cancer (CRC) care. Many organisations opted to perform CRC resections in 'cold' sites. Infrastructure in Northumbria Healthcare NHS Foundation Trust (NHCT) necessitated co-locating CRC care with 'hot' COVID streams but with additional precautions. This study aimed to evaluate that approach for a consecutive series of CRC cases, diagnosed before and during the COVID-19 pandemic.

METHODS

A prospectively populated data set of CRC patients diagnosed between 1 April 2019 and 30 September 2020 was used. Patients presenting before 1 April 2020 were considered 'pre-COVID' and those presenting subsequently as 'COVID era'.

RESULTS

Some 344 cases were diagnosed in the 12 months 'pre-COVID' and 166 in the 6 months of the 'COVID era'. The median numbers of days from referral to diagnosis (21 vs 20, p=0.373) and operation (63 vs 61, p=0.208) were unchanged. The 'COVID era' saw an increase in the proportion of radiological diagnoses (39.5% vs 53.0%, p=0.004) with an associated decrease in endoscopic diagnoses (56.7% vs 45.8%, p=0.021). Rates of inoperable (1.5% vs 1.2%, p=0.821), obstructing (11.0% vs 16.2%, p=0.272) and perforated tumours (0.6% vs 1.5%, p=0.492) remained the same. One patient developed COVID-19 perioperatively. Rates of laparoscopic operation (59.5% vs 61.8%, p=0.751), anastomotic leak (6.4% vs 5.9%, p=0.891), re-operative surgery (10.4% vs 4.4%, p=0.138), primary stoma (40.5% vs 32.4%, p=0.244) and 90-day mortality (0.6% vs 1.5%, p=0.492) did not change.

CONCLUSIONS

With appropriate infection control measures, it may be safe to continue providing standard elective and urgent CRC care without access to a 'COVID clean' site.

OS09.7.A Quality of life outcomes in patients with incidental and operated meningiomas: the QUALMS study

BACKGROUND

Long-term Health-Related Quality of Life (HRQoL) is an important measure of patient wellbeing. There is a paucity of studies evaluating HRQoL in meningioma patients.

MATERIAL AND METHODS

Cross-sectional study of adult patients with an incidental or symptomatic intracranial meningioma. Patients with less than 5 years of follow-up, a history of craniospinal radiation or neurofibromatosis type 2 were excluded. HRQoL was evaluated with SF-36, EORTC QLQ-C30 and EORTC QLQ-BN20 questionnaires. Outcome determinants were evaluated using a multi-variable linear regression analysis, adjusted for patient, tumour and treatment characteristics, and duration of follow-up.

RESULTS

699 patients were invited to participate and 246 responded: 118 (48%) had an incidental meningioma. Mean age at diagnosis was 56.8 years (SD=13) and 81% were female. Median time from diagnosis to completion of questionnaire was 8.5 years (IQR 6.8–11.5). During follow-up, 158 patients (64.2%) had at least one operation for their meningioma and 47 patients (19.1%) had radiotherapy. Of those operated, 126 (79.7%) had WHO grade 1 and 24 (15.2%) had grade 2 meningiomas. Compared to normative population values, meningioma patients reported a worse SF-36 general health score (mean 61.9 vs 56.5, P=0.003) but a similar QLQ-C30 global health score (mean 62.3 vs 65.8, P=0.039), worse SF-36 and QLQ-C30 physical functioning scores (mean 74.1 vs 64.6, P<0.001 and mean 81.8 vs 76.5, P=0.007) and similar SF-36 and QLQ-C30 emotional health scores (mean 72.2 vs 70.9, P=0.367 and mean 71.0 vs 71.9, P=0.960). QLQ-C30 cognitive functioning was worse (mean 80.5 vs 71.4, P<0.001). Compared to the meningioma literature, QLQ-BN20 seizure burden was similar (mean 2.0 vs 1.6, P=0.760). A worse performance status at diagnosis was associated with an inferior QLQ-C30 global health score (β-coefficient=-4.9 [95% CI -9.1-(-)0.6] P=0.024). Number of surgeries was significantly associated with a worse QLQ-C30 cognitive functioning score (β-coefficient=-7.0 [95% CI -13.2-(-)0.9], P=0.025). Anti-epileptic drug use was associated with a significantly worse QLQ-C30 emotional health score (β-coefficient=-10.9 [95% CI -21.7-(-)0.01], P=0.050).

CONCLUSION

Meningioma patients have long-term HRQoL impairments affecting their physical and cognitive functions. An understanding that multiple surgeries affects cognitive function, and the need for anti-epileptic drugs equate to poorer emotional health, could help target appropriate therapies and support in the future.

P14.02 The Natural History of a Residual Intracranial Meningioma- Volumetric Growth and Predictors of Progression

BACKGROUND

Resection of meningioma leaves residual solid tumour in ~25% of patients. Selection for further treatment and follow-up strategy may benefit from knowledge of volumetric growth and associated prognostic factors.

MATERIAL AND METHODS

Growth rates were assessed using a linear mixed effects model, in a retrospective adult cohort that underwent subtotal resection of meningioma (2004–2018). Endpoints were re-treatment, end of follow-up or death. Cox regression analysis was used to identify prognostic factors for progression, defined using the Response Assessment in Neuro-Oncology (RANO) volumetric criteria.

RESULTS

236 patients were included. Mean age at surgery was 56.3 years (SD=13.7) and 73.7% were female. WHO grades were 1 (n=195, 82.6%), 2 (n=40, 16.9%) and 3 (n=1, 0.5%). Adjuvant fractionated radiotherapy (fRT) was administered to 34 patients (14.4%), with no propensity towards higher WHO grade or residual volume. Median pre-operative meningioma and post-operative residual volumes were 34.0cm3 (IQR 16.0–63.0) and 2.0cm3 (IQR 0.8–5.2), respectively. Median follow-up was 64 months (IQR 42–104). Median absolute growth rate (AGR) and relative growth rate (RGR) were 0.1cm3/year and 4.3%/year, respectively. According to RANO criteria, 132 (55.9%) patients progressed, of which 13 (9.8%) developed symptoms. Median progression-free survival was 56 months (95% CI 43.1–69.0). Multivariable analysis identified adjuvant fRT (HR 1.7, [95% CI 1.0–2.8], P=0.046), skull base location (HR 1.5, [95% CI 1.0–2.4], P=0.047) and Ki-67 index (HR 3.7 [95% CI 1.3–10.8], P=0.017) as prognostic factors for volumetric progression. WHO grade was not significant (HR 1.0, [95% CI 0.5–1.7], P=0.905). Forty-nine patients who progressed (37.1%) underwent further treatment: fRT (n=19), re-operation (n=15), Stereotactic radiosurgery (SRS) (n=10) and surgery+adjuvant fRT (n=5). Of those, 8 (16.3%) progressed further (after re-operation [n=6] and SRS [n=2]). Seven were treated with a 2nd re-operation (n=3), fRT (n=3), and SRS (n=1). One patient progressed after a 2nd reoperation and was treated with SRS, after which they remained stable. Median survival was not reached. 5- and 10-year overall survival (OS) was 96% and 86% respectively.

CONCLUSION

Growth rates of a residual meningioma vary with a dichotomy observed in progression rates. Half of patients with a residual meningioma showed radiological progression requiring multiple treatment to control the tumour. The other half demonstrate a more indolent course. Skull base location and higher Ki67 are important prognostic factors for progression and therefore, should be considered to stratify patients for adjuvant radiotherapy.

TM1-5 Optimising observation strategies for incidentally discovered intracranial meningiomas

Objectives

Develop a model to identify incidental meningiomas at risk of observation failure.

Design

Retrospective study (2007–2015).

Subjects

385 patients. Mean age 62.6 years.

Methods

Observation failure was defined as: new symptoms, MRI progression (absolute growth rate 2 cm3/year or absolute growth rate 1 cm3/year +relative growth rate 30%/year) or loss of treatment options. A prognostic model was developed using MRI and patient comorbidity.

Results

Over a median of 36 months, 44 (10.9%) meningiomas failed observation. Median time to failure was 33 months. Model parameters were based on statistical and clinical considerations and included: increasing tumour size (HR=2.17 [95% CI=1.53–3.09], p<0.001), peritumoural signal change (HR=1.58 [95% CI=0.65–3.85], p=0.313), FLAIR/T2 hyperintense meningiomas (HR=10.6 [95% CI=5. 39–21.0], p<0.001) and proximity to neurovascular structures (HR=1.38 [95% CI=0.74–2.56], p=0.314). Patients were stratified based on the model into low, medium and high-risk groups and rates of failed observation at 5 years were 3%, 28% and 75% respectively. Low-risk patients had small meningiomas, free of all risk factors. After 5 years of follow-up the probability of failure plateaued in all risk groups. Older patients with comorbidities were 15-times more likely to die than to receive intervention at 5 years following diagnosis, regardless of risk group.

Conclusions

Most meningiomas remain clinically and radiologically stable. Stratifying follow-up according to risk-group has the potential to reduce the cost to healthcare.

WP1-14 A systematic review to evaluate different management strategies for incidental intracranial meningiomas

Objectives

Evaluate the outcomes of differing management strategies for incidental intracranial meningiomas.

Design

Systematic review.

Subjects

Studies with ≥10 patients≥16 years of age diagnosed radiologically with an incidental intracranial meningioma.

Methods

PRISMA compliant methods were used to scan 6 databases up to September 2017. PROSPERO ID: CRD42017077928.

Results

Twenty retrospective studies (n=2130 patients) were included. Initial management strategies at diagnosis were: 27% (n=560) surgery, 22% (n=450) SRS and 51% (n=1040) active monitroing with a mean follow-up of 49.5 months (SD=29.3). 21% (n=220) of patients in the active monitoring cohort eventually had or were recommended an intervention due to: radiological progression (n=153), development of symptoms (n=66) and patient preference (n=1). Mean time-to-intervention was 24.8 months (SD=18.2). 94% (n=207) of interventions were within 5 years. The definition of ‘growth’ and the radiological surveillance regimens varied widely. Morbidity rates following surgery and SRS, accounting for cross over, were 15% and 22% respectively. Surgery revealed benign histology in 94% of the cases. Quality of life is improperly examined.

Conclusions

The management of patients with incidental intracranial meningiomas varies widely. Most patients who develop clinical or radiological progression will do so within 5 years of diagnosis. Intervention at diagnosis may result in unnecessary overtreatment. Prospective data is needed to develop a risk calculator for managing incidental meningioma.

The crystal structure of cesbronite, Cu3TeO4(OH)4: a novel sheet tellurate topology

The crystal structure of cesbronite has been determined using single-crystal X-ray diffraction and supported by electron-microprobe analysis, powder diffraction and Raman spectroscopy. Cesbronite is orthorhombic, space group Cmcm, with a = 2.93172 (16), b = 11.8414 (6), c = 8.6047 (4) Å and V = 298.72 (3) Å3. The chemical formula of cesbronite has been revised to CuII 3TeVIO4(OH)4 from CuII 5(TeIVO3)2(OH)6·2H2O. This change has been accepted by the Commission on New Minerals, Nomenclature and Classification of the International Mineralogical Association, Proposal 17-C. The previously reported oxidation state of tellurium has been shown to be incorrect; the crystal structure, bond valence studies and charge balance clearly show tellurium to be hexavalent. The crystal structure of cesbronite is formed from corrugated sheets of edge-sharing CuO6 and (Cu0.5Te0.5)O6 octahedra. The structure determined here is an average structure that has underlying ordering of Cu and Te at one of the two metal sites, designated as M, which has an occupancy Cu0.5Te0.5. This averaging probably arises from an absence of correlation between adjacent polyhedral sheets, as there are two different hydrogen-bonding configurations linking sheets that are related by a ½a offset. Randomised stacking of these two configurations results in the superposition of Cu and Te and leads to the Cu0.5Te0.5 occupancy of the M site in the average structure. Bond-valence analysis is used to choose the most probable Cu/Te ordering scheme and also to identify protonation sites (OH). The chosen ordering scheme and its associated OH sites are shown to be consistent with the revised chemical formula.

Mitotic Activity in Glioblastoma Correlates with Estimated Extravascular Extracellular Space Derived from Dynamic Contrast-Enhanced MR Imaging

BACKGROUND AND PURPOSE

A number of parameters derived from dynamic contrast-enhanced MR imaging and separate histologic features have been identified as potential prognosticators in high-grade glioma. This study evaluated the relationships between dynamic contrast-enhanced MRI-derived parameters and histologic features in glioblastoma multiforme.

MATERIALS AND METHODS

Twenty-eight patients with newly presenting glioblastoma multiforme underwent preoperative imaging (conventional imaging and T1 dynamic contrast-enhanced MRI). Parametric maps of the initial area under the contrast agent concentration curve, contrast transfer coefficient, estimate of volume of the extravascular extracellular space, and estimate of blood plasma volume were generated, and the enhancing fraction was calculated. Surgical specimens were used to assess subtype and were graded (World Health Organization classification system) and were assessed for necrosis, cell density, cellular atypia, mitotic activity, and overall vascularity scores. Quantitative assessment of endothelial surface area, vascular surface area, and a vascular profile count were made by using CD34 immunostaining. The relationships between MR imaging parameters and histopathologic features were examined.

RESULTS

High values of contrast transfer coefficient were associated with the presence of frank necrosis (P = .005). High values of the estimate of volume of the extravascular extracellular space were associated with a fibrillary histologic pattern (P < .01) and with increased mitotic activity (P < .05). No relationship was found between mitotic activity and histologic pattern, suggesting that the correlation between the estimate of volume of the extravascular extracellular space and mitotic activity was independent of the histologic pattern.

CONCLUSIONS

A correlation between the estimate of volume of the extravascular extracellular space and mitotic activity is reported. Further work is warranted to establish how dynamic contrast-enhanced MRI parameters relate to more quantitative histologic measurements, including markers of proliferation and measures of vascular endothelial growth factor expression.

Screen-detected colorectal cancers are associated with an improved outcome compared with stage-matched interval cancers

Background:

Colorectal cancers (CRCs) detected through the NHS Bowel Cancer Screening Programme (BCSP) have been shown to have a more favourable outcome compared to non-screen-detected cancers. The aim was to identify whether this was solely due to the earlier stage shift of these cancers, or whether other factors were involved.

Methods:

A combination of a regional CRC registry (Northern Colorectal Cancer Audit Group) and the BCSP database were used to identify screen-detected and interval cancers (diagnosed after a negative faecal occult blood test, before the next screening round), diagnosed between April 2007 and March 2010, within the North East of England. For each Dukes' stage, patient demographics, tumour characteristics, and survival rates were compared between these two groups.

Results:

Overall, 322 screen-detected cancers were compared against 192 interval cancers. Screen-detected Dukes' C and D CRCs had a superior survival rate compared with interval cancers (P=0.014 and P=0.04, respectively). Cox proportional hazards regression showed that Dukes' stage, tumour location, and diagnostic group (HR 0.45, 95% CI 0.29–0.69, P<0.001 for screen-detected CRCs) were all found to have a significant impact on the survival of patients.

Conclusions:

The improved survival of screen-detected over interval cancers for stages C and D suggest that there may be a biological difference in the cancers in each group. Although lead-time bias may have a role, this may be related to a tumour's propensity to bleed and therefore may reflect detection through current screening tests.

Topical photodynamic therapy following excisional wounding of human skin increases production of transforming growth factor-β3 and matrix metalloproteinases 1 and 9, with associated improvement in dermal matrix organization

BACKGROUND

Animal studies report photodynamic therapy (PDT) to improve healing of excisional wounds; the mechanism is uncertain and equivalent human studies are lacking.

OBJECTIVES

To explore the impact of methyl aminolaevulinate (MAL)-PDT on clinical and microscopic parameters of human cutaneous excisional wound healing, examining potential modulation through production of transforming growth factor (TGF)-β isoforms.

METHODS

In 27 healthy older men (60-77 years), a 4-mm punch biopsy wound was created in skin of the upper inner arm and treated with MAL-PDT three times over 5 days. An identical control wound to the contralateral arm was untreated and both wounds left to heal by secondary intention. Wounds were re-excised during the inflammatory phase (7 days, n = 10), matrix remodelling (3 weeks, n = 8) and cosmetic outcome/dermal structure (9 months, n = 9). Production of TGF-β1, TGF-β3 and matrix metalloproteinases (MMPs) was assessed by immunohistochemistry alongside microscopic measurement of wound size/area and clinical assessment of wound appearance.

RESULTS

MAL-PDT delayed re-epithelialization at 7 days, associated with increased inflammation. However, 3 weeks postwounding, treated wounds were smaller with higher production of MMP-1 (P = 0·01), MMP-9 (P = 0·04) and TGF-β3 (P = 0·03). TGF-β1 was lower than control at 7 days and higher at 3 weeks (both P = 0·03). At 9 months, MAL-PDT-treated wounds showed greater, more ordered deposition of collagen I, collagen III and elastin (all P < 0·05).

CONCLUSIONS

MAL-PDT increases MMP-1, MMP-9 and TGF-β3 production during matrix remodelling, ultimately producing scars with improved dermal matrix architecture.

Imaging biomarkers of angiogenesis and the microvascular environment in cerebral tumours

Conventional contrast-enhanced CT and MRI are now in routine clinical use for the diagnosis, treatment and monitoring of diseases in the brain. The presence of contrast enhancement is a proxy for the pathological changes that occur in the normally highly regulated brain vasculature and blood-brain barrier. With recognition of the limitations of these techniques, and a greater appreciation for the nuanced mechanisms of microvascular change in a variety of pathological processes, novel techniques are under investigation for their utility in further interrogating the microvasculature of the brain. This is particularly important in tumours, where the reliance on angiogenesis (new vessel formation) is crucial for tumour growth, and the resulting microvascular configuration and derangement has profound implications for diagnosis, treatment and monitoring. In addition, novel therapeutic approaches that seek to directly modify the microvasculature require more sensitive and specific biological markers of baseline tumour behaviour and response. The currently used imaging biomarkers of angiogenesis and brain tumour microvascular environment are reviewed.

Advanced magnetic resonance imaging biomarkers of cerebral metastases

There are a number of magnetic resonance imaging techniques available for use in the diagnosis and management of patients with cerebral metastases. This article reviews these techniques, in particular, the advanced imaging methodologies from which quantitative parameters can be derived, the role of these imaging biomarkers have in distinguishing metastases from primary central nervous system tumours and tumour mimics, and metrics that may be of value in predicting the origin of the primary tumour.

Comparison of screen-detected and interval colorectal cancers in the Bowel Cancer Screening Programme

Background:

The NHS Bowel Cancer Screening Programme (BCSP) offers biennial faecal occult blood testing (FOBt) followed by colonoscopy after positive results. Colorectal cancers (CRCs) registered with the Northern Colorectal Cancer Audit Group database were cross-referenced with the BCSP database to analyse their screening history.

Methods:

The CRCs in the screening population between April 2007 and March 2010 were identified and classified into four groups: control (diagnosed before first screening invite), screen-detected, interval (diagnosed between screening rounds after a negative FOBt), and non-uptake (declined screening). Patient demographics, tumour characteristics and survival were compared between groups.

Results:

In all, 511 out of 1336 (38.2%) CRCs were controls; 825 (61.8%) were in individuals invited for screening of which 322 (39.0%) were screen detected, 311 (37.7%) were in the non-uptake group, and 192 (23.3%) were interval cancers. Compared with the control and interval cancer group, the screen-detected group had a higher proportion of men (P=0.002, P=0.003 respectively), left colon tumours (P=0.007, P=0.003), and superior survival (both P<0.001). There was no difference in demographics, tumour location/stage, or survival between control and interval groups.

Conclusion:

The FOBt is better at detecting cancers in the left colon and in men. The significant numbers of interval cancers weren’t found to have an improved outcome compared with the non-screened population.

Impact of deprivation on short- and long-term outcomes after colorectal cancer surgery

Background

The aim of the study was to determine the association between short- and long-term outcomes and deprivation for patients undergoing operative treatment for colorectal cancer in the Northern Region of England.

Methods

This was a retrospective analytical study based on the Northern Region Colorectal Cancer Audit Group database for the period 1998–2002. The Index of Multiple Deprivation 2004, an area-based measure, was recalibrated and used to quantify deprivation. Patients were ranked based on their postcode of residence and grouped into five categories.

Results

Of 8159 patients in total, 7352 (90·1 per cent) had surgery; 6953 (94·6 per cent) of the 7352 patients underwent tumour resection and 4935 (67·7 per cent) of 7294 had a margin-negative (R0) resection. Deprivation was not associated with age, sex, tumour site, stage or other tumour-related factors. Compared with the most affluent group, the most deprived patients had fewer elective operations (72·9 versus 76·4 per cent; P = 0·014), more adverse co-morbidity (P &lt; 0·001) and fewer curative resections (65·5 versus 71·2 per cent; P &lt; 0·001). In multivariable analysis, deprivation was not an independent predictor of postoperative death (odds ratio (OR) 0·72, 95 per cent confidence interval 0·48 to 1·06; P = 0·101) but it was a predictor of curative resection (OR 1·24, 1·01 to 1·52; P = 0·042), overall survival (HR 0·83, 0·73 to 0·95; P = 0·006) and relative survival (HR 0·74, 0·58 to 0·95; P = 0·023).

Conclusion

Deprivation, both independently and by influencing other surgical predictors, impacts on short- and long-term outcomes of patients with colorectal cancer.

Effect of the circumferential resection margin on survival following rectal cancer surgery

BACKGROUND

The aim was to determine the effect of the circumferential resection margin (CRM) on overall survival following surgical excision of rectal cancer.

METHODS

The effect of CRM on survival was examined by case mix-adjusted analysis of patients undergoing potentially curative excision of a rectal cancer between 1998 and 2002.

RESULTS

Of 1896 patients, 1561 (82.3 per cent) had recorded data on the CRM. In 232 patients (14.9 per cent) tumour was found 1 mm or less from the CRM. In 370 patients (23.7 per cent) it was over 1 mm but no more than 5 mm from the CRM, and in 288 (18.4 per cent) it was over 5 mm but no more than 10 mm from the CRM. The remaining 671 patients (43.0 per cent) had a CRM exceeding 10 mm. Overall 5-year survival rates for these groups were 43.2, 51.7, 66.6 and 66.0 per cent respectively. Compared with patients with a CRM exceeding 10 mm, the adjusted risk of death was significantly increased for patients with a CRM of 1 mm or less (hazard ratio (HR) 1.61, P < 0.001) and those with a margin greater than 1 mm but no larger than 5 mm (HR 1.35, P = 0.005). There was no added risk for patients with tumour more than 5 mm but 10 mm or less from the CRM (HR 1.02, P = 0.873). The adverse effect of a CRM greater than 1 mm but no larger than 5 mm was found particularly in mid-rectal cancers.

CONCLUSION

A predicted CRM of 5 mm or less on preoperative staging should be considered for neoadjuvant treatment.

Volume-outcome analysis of colorectal cancer-related outcomes

BACKGROUND

Significant associations between caseload and surgical outcomes highlight the conflict between local cancer care and the need for centralization. This study examined the effect of hospital volume on short-term outcomes and survival, adjusting for the effect of surgeon caseload.

METHODS

Between 1998 and 2002, 8219 patients with colorectal cancer were identified in a regional population-based audit. Outcomes were assessed using univariable and multivariable analysis to allow case mix adjustment. Surgeons were categorized as low (26 or fewer operations annually), medium (27-40) or high (more than 40) volume. Hospitals were categorized as low (86 or fewer), medium (87-109) or high (more than 109) volume.

RESULTS

Some 7411 (90.2 per cent) of 8219 patients underwent surgery with an anastomotic leak rate of 2.9 per cent (162 of 5581), perioperative mortality rate of 8.0 per cent (591 of 7411) and 5-year survival rate of 46.8 per cent. Medium- and high-volume surgeons were associated with significantly better operative mortality (odds ratio (OR) 0.74, P = 0.010 and OR 0.66, P = 0.002 respectively) and survival (hazard ratio (HR) 0.88, P = 0.003 and HR 0.93, P = 0.090 respectively) than low-volume surgeons. Rectal cancer survival was significantly better in high-volume versus low-volume hospitals (HR 0.85, P = 0.036), with no difference between medium- and low-volume hospitals (HR 0.96, P = 0.505).

CONCLUSION

This study has confirmed the relevance of minimum volume standards for individual surgeons. Organization of services in high-volume units may improve survival in patients with rectal cancer.

Enhancing fraction in glioma and its relationship to the tumoral vascular microenvironment: A dynamic contrast-enhanced MR imaging study

BACKGROUND AND PURPOSE

EnF is a newly described measure of proportional tumor enhancement derived from DCE-MR imaging. The aim of this study was to assess the relationship between EnF and the more established DCE-MR imaging parameters: K(trans), v(e), and v(p).

MATERIALS AND METHODS

Forty-two patients with 43 gliomas (16 grade II, 3 grade III, and 24 grade IV) were studied. Imaging included pre- and postcontrast T1-weighted sequences through the lesion and T1-weighted DCE-MR imaging. Parametric maps of EnF, K(trans), v(e), and v(p) were generated. Voxels were classified as enhancing if the IAUC was positive (EnF(IAUC)(60>0)). A threshold of IAUC > 2.5 mmol.s was used to generate EnF(IAUC)(60>2.5). Both measures of EnF were compared with the DCE-MR imaging parameters (K(trans), v(e), and v(p)).

RESULTS

In grade II gliomas, EnF(IAUC60>0) and EnF(IAUC60>2.5) correlated with v(p) (R(2) = 0.6245, P < .0005; and R(2) = 0.4727, P = .003) but not with K(trans) or v(e). In grade IV tumors, both EnF(IAUC60>0) and EnF(IAUC60>2.5) correlated with K(trans) (R(2) = 0.3501, P = .001; and R(2) = 0.4699, P < .0005) and v(p) (R(2) = 0.1564, P = .01; and R(2) = 0.2429, P = .007), but not with v(e). Multiple regression analysis showed K(trans) as the only independent correlate of both EnF(IAUC60>0) and EnF(IAUC60>2.5) for grade IV tumors.

CONCLUSIONS

This study suggests that in grade II tumors, EnF reflects v(p) and varies due to changes in vascular density. In grade IV gliomas, EnF is affected by K(trans) with secondary associated changes in v(p).

Candidate biomarkers of extravascular extracellular space: a direct comparison of apparent diffusion coefficient and dynamic contrast-enhanced MR imaging--derived measurement of the volume of the extravascular extracellular space in glioblastoma multiforme

BACKGROUND AND PURPOSE

ADC measurements have been shown to have an inverse relationship with tumor cell density. DCE-MR imaging modeling techniques can produce a measurement of the v(e), which would also be expected to have an inverse relationship with cell density. The objective of this study was to test the hypothesis that areas of increased cellularity, and therefore low ADC, would be expected to have a small EES (low v(e)).

MATERIALS AND METHODS

Nineteen patients with GBM were recruited. All imaging was performed before surgery on a 3T MR imaging scanner. Imaging included diffusion tensor imaging, T1-weighted DCE-MR imaging, and anatomic sequences. Tumor VOIs were defined on the anatomic images and modified to contain only enhancing voxels. Parametric maps of ADC and v(e) were generated. Statistical analysis of ADC and v(e) was performed on both a voxel-by-voxel basis and comparison of median values.

RESULTS

No correlation was demonstrated between ADC and v(e) in either a voxel-by-voxel analysis or comparison of median values (P = .124).

CONCLUSIONS

This study failed to demonstrate a correlation between ADC and v(e). This is important because it suggests that though the mechanisms underlying these parameters are theoretically similar, they actually reflect different aspects of tumor microenvironment. Consequently ADC and v(e) should be considered to provide independent information about the properties of the EES.

Involvement of surgical trainees in surgery for colorectal cancer and their effect on outcome

OBJECTIVE

Surgical training in the UK is undergoing substantial changes. This study assessed: 1) the training opportunities available to trainees in operations for colorectal cancer, 2) the effect of colorectal specialization on training, and 3) the effect of consultant supervision on anastomotic complications, postoperative stay, operative mortality and 5-year survival.

METHOD

Unadjusted and adjusted comparisons of outcomes were made for unsupervised trainees, supervised trainees and consultants as the primary surgeon in 7411 operated patients included in the Northern Region Colorectal Cancer Audit between 1998 and 2002.

RESULTS

Surgery was performed in 656 (8.8%) patients by unsupervised trainees and in 1578 (21.3%) patients by supervised trainees. Unsupervised operations reduced from 182 (12.4%) in 1998 to 82 (6.1%) in 2002 (P < 0.001). Consultants with a colorectal specialist interest were more likely than nonspecialists to be present at surgical resections (OR 1.35, 1.12-1.63, P = 0.001) and to provide supervised training (OR 1.34, 1.17-1.53, P < 0.001). Patients operated on by unsupervised trainees were more often high-risk patients, however, consultant presence was not significantly associated with operative mortality (OR 0.83, 0.63-1.09, P = 0.186) or survival (HR 1.02, 0.92-1.13, P = 0.735) in risk-adjusted analysis. Supervised trainees had a case-mix similar to consultants, with shorter length of hospital stay (11.4 vs 12.4 days, P < 0.001), but similar mortality (OR 0.90, 0.71-1.16, 0.418) and survival (HR 0.96, 0.89-1.05, P = 0.378).

CONCLUSION

One third of patients were operated on by trainees, who were more likely to perform supervised resections in colorectal teams. There was no difference in anastomotic leaks rates, operative mortality or survival between unsupervised trainees, supervised trainees and consultants when case-mix adjustment was applied. This study would suggest that there is considerable underused training capacity available.

The use of central venous cannulae in neuroanaesthesia

A postal questionnaire was sent to all UK consultant members of the Neuroanaesthesia Society to ascertain whether there was any consensus on indications for use and route of insertion of central venous cannulae in elective neuroanaesthetic practice. Five brief clinical scenarios were presented. Of 179 respondents, 98% indicated that they would insert a central venous cannula into patients requiring excision of an acoustic neuroma in the sitting position, 76% for clipping of an intracranial aneurysm and 75% for resection of an arteriovenous malformation. The antecubital fossa was the preferred route of insertion for 43.5% of respondents with 36.5% preferring the internal jugular approach. The subclavian (17%) and femoral (3%) routes were unpopular first-choice approaches. A significant proportion of respondents (43.5%) do not routinely order a chest X-ray at any stage following pre-operative central venous cannulation. The indications for use and advantages and disadvantages of each route of insertion, with reference to neuro-anaesthetic practice, are discussed.

Do cerebral blood volume and contrast transfer coefficient predict prognosis in human glioma?

INTRODUCTION

Noninvasive measurements of cerebral blood volume (CBV) and contrast transfer coefficient (K(trans)) have potential benefits in the diagnosis and therapeutic management of adult glioma. This study examines the relationship between CBV, K(trans), and overall survival.

METHODS AND MATERIALS

Twenty-seven adult patients with glioma underwent T1-weighted dynamic contrast-enhanced MR imaging, and parametric maps of CBV and K(trans) were calculated. The relationship of histologic grade, CBV, K(trans), age, sex, surgical resection, and use of adjuvant therapy to survival were analyzed by using the logrank method and Cox regression analysis. The Kaplan-Meier method for displaying survival curves was used. The relationship of factors such as comorbidity, elevated intracranial pressure, size of nonenhancing tumor, and peritumoral edema were not considered.

RESULTS

Both CBV (P < .01) and K(trans) (P < .01) show a significant relationship to histologic grade. CBV (P = .004), K(trans) (P = .008), and histologic grade (P < .001) all demonstrate a significant association with patient survival when analyzed individually. Cox regression analysis identified only histologic grade (P < .01) and K(trans) (P < .05) as independent significant prognostic indicators. Examination of survival data from high-grade (III and IV) tumors demonstrated a linear relationship between K(trans) and patient survival (P < .01).

CONCLUSION

This study suggests a direct relationship between K(trans) and length of survival in high-grade gliomas, which could be of clinical importance. CBV relates directly to histologic grade but provides no independent prognostic information over and above that provided by grade. Further large prospective studies should be planned to test whether this observation holds true.

InsP(3)-induced Ca(2+) release in permeabilized invertebrate photoreceptors: a link between phototransduction and Ca(2+) stores

Using the low-affinity fluorescent Ca(2+) indicators, Mag-Fura-2 and Mag-Fura Red, we studied light- and InsP(3)-induced Ca(2+) release in permeabilized microvillar photoreceptors of the medicinal leech, Hirudo medicinalis. Two major components of the phosphoinositide signaling pathway, phospholipase-C and the InsP(3) receptor, were characterized immunologically and appropriately localized in photoreceptors. Whereas phospholipase-C was abudantly expressed in photoreceptive microvilli, InsP(3) receptors were found mostly in submicrovillar endoplasmic reticulum (SER). Permeabilization of the peripheral plasma membrane with saponin allowed direct measurements of luminal free Ca(2+) concentration (Ca(L)) changes. Confocal Ca(2+) imaging using Mag-Fura Red demonstrated that Ins(1,4,5)P(3) mobilizes Ca(2+) from SER. As detected with Mag-Fura-2, a brief 50ms light flash activated rapid Ca(2+) depletion of SER, followed by an effective refilling within 1min of dark adaptation after the light flash. Sensitivity to Ins(1,4,5)P(3) of the Ca(2+) release from SER in leech photoreceptors was accompanied by irreversible uncoupling of phototransduction from Ca(2+) release. Depletion of Ca(2+) stores was induced by Ins(1,4,5)P(3)(EC(50)= 4.75 microM) and the hyper-potent agonist adenophostin A (EC(50)/40nM) while the stereoisomer L-myo Ins(1,4,5)P(3) was totally inactive. Ins(1,4,5)P(3)- or adenophostin A-induced Ca(2+) release was inhibited by 0.1-1mg/ml heparin. The Ca(2+) pump inhibitors, cyclopiazonic acid and thapsigargin, in the presence of Ins(1,4,5)P(3), completely depleted Ca(2+) stores in leech photoreceptors.

Colonic crypt cell proliferation state assessed by whole crypt microdissection in sporadic neoplasia and familial adenomatous polyposis

BACKGROUND

It has yet to be established whether proliferative activity in the macroscopically normal colonic mucosa is causally correlated with neoplastic risk. Measurement of proliferative activity in human subjects is of necessity usually undertaken using indirect methods with inherent limitations, and relatively little has been published on the effect of normal biological variables on such indices.

AIMS

To establish the validity of mitosis counts following whole crypt microdissection as an index of the crypt cell proliferative state (CCPS) and to examine the effect of normal biological variables (age, sex, and colonic site) and colonic neoplasia on the mitotic index in macroscopically normal human colon.

SUBJECTS

Mucosal samples were obtained at colectomy or colonoscopy from 107 individuals (24 controls, 23 sporadic adenoma patients, 31 sporadic carcinoma patients, and 29 patients with familial adenomatous polyposis (FAP)).

METHODS

Mucosal specimens were hydrated, hydrolysed, and small groups of crypts separated from the main specimen under a dissecting microscope. The total number of mitoses/crypt were counted by one observer for each of 10 complete crypts.

RESULTS

Validation work established that whole crypt mitoses counts were reliable and reproducible. There was no relation between age and mean mitoses/crypt (Pearson correlation coefficient -0.1). The CCPS count was higher for males than for females (difference in means 2.8 (95% confidence interval 0.80-4.66)) among controls but there was no gender difference in the three disease groups. For all disease groups and controls, the crypt mitotic count showed a significant linear increase (p=0.004) from the rectum to the caecum. Biopsies from within 5 cm of the macroscopic margin of a carcinoma (near) gave a mean mitosis count of 12.6 while those from more than 10 cm (far) were lower but not significantly so (p=0.12) with a count of 9.0. The mean mitoses/crypt were similar for the controls and adenomas (5.6 and 4.7, respectively) but greater for the cancers and especially for FAP (8.3 and 14.2, respectively). Statistical analysis confirmed that there were significant differences (p<0.05) between controls and all disease groups together, between sporadic disease and FAP, and between adenoma and carcinoma subjects at each of the four colonic sites. Post hoc comparison by t test showed significantly greater CCPS for FAP compared with controls (p<0.001) and for sporadic cancer versus controls (p=0.04).

CONCLUSIONS

Whole crypt microdissection and mitosis counting is a reliable, reproducible, and robust technique for assessing CCPS in the human colon. CCPS is unaffected by age but increases from the distal to the proximal colon. CCPS is increased if a sporadic cancer is present and markedly increased in FAP. However, the precise relation of an increased CCPS to the neoplastic process remains uncertain.

Operative field contamination by the sweating surgeon

BACKGROUND

There are a number of factors relating to the host, bacteria and wound that are important in the development of wound infection. The effect of the surgeon sweating has not been previously reported.

METHODS

Ten surgeons performed a mock total hip joint operation under sterile conditions while not sweating and then repeated the operation while sweating. Settle plates were used to quantify the bacterial counts in the operative field in both phases.

RESULTS

For each subject a mean of 3.3 colony forming units (c.f.u.) were present in the non-sweating phase and 6.9 c.f.u. were present in the sweating phase (P < 0.05). Organisms grown were normal skin flora.

CONCLUSION

The sweating surgeon may be more likely to contaminate the surgical field than the non-sweating surgeon. It is important for orthopaedic surgeons, especially those performing joint replacement surgery, to be aware of this and to take measures to minimize sweating in the operating theatre.

myo-inositol 1,4,6-trisphosphorothioate and myo-inositol 1,3, 6-trisphosphorothioate: partial agonists with very low intrinsic activity at the platelet myo-inositol 1,4,5-trisphosphate receptor

Racemic mixtures and enantiomerically pure D-isomers of both myo-inositol 1,3,6-trisphosphorothioate [Ins(1,3,6)PS(3)] and myo-inositol 1,4,6-trisphosphorothioate [Ins(1,4,6)PS(3)], prepared by total synthesis, were examined in Ca(2+) flux and binding assays. Both D-Ins(1,3,6)PS(3) and D-Ins(1,4,6)PS(3) were shown to be low intrinsic activity partial agonists at the platelet myo-inositol 1,4, 5-trisphosphate [Ins(1,4,5)P(3)] receptor, releasing less than 20% of the Ins(1,4,5)P(3)-sensitive Ca(2+) store. D-Ins(1,4,6)PS(3) displaced specifically bound [(3)H]Ins(1,4,5)P(3) from rat cerebellar membranes, although displacement was some 34-fold weaker than by D-Ins(1,4,5)P(3). D-Ins(1,4,6)PS(3) displaced [(3)H]Ins(1,4, 5)P(3) from cerebellar membranes with roughly twice the affinity of DL-Ins(1,4,6)PS(3) (IC(50) value = 1.4 +/- 0.35 microM compared with 2.15 +/- 0.13 microM), whereas D-Ins(1,3,6)PS(3) displaced [(3)H]Ins(1,4,5)P(3) with roughly twice the affinity of DL-Ins(1,3, 6)PS(3) (IC(50) value = 17.5 +/- 5.8 microM compared with 34 +/- 10 microM), confirming that the activity of both these phosphorothioates resides in their D-enantiomers. Increasing concentrations of either D-Ins(1,3,6)PS(3) or D-Ins(1,4,6)PS(3) were able to partially antagonize Ca(2+) release induced by submaximal concentrations of Ins(1,4,5)P(3), an inhibition that could be overcome by increasing the concentration of Ins(1,4,5)P(3), suggesting competition for binding at the Ins(1,4,5)P(3)-R. The only low-efficacy partial agonists at the Ins(1,4,5)P(3)-R discovered to date have been phosphorothioates; the novel D-Ins(1,3,6)PS(3) and D-Ins(1,4,6)PS(3) can now be added to this small group of analogs. However, D-Ins(1,4,6)PS(3) has a relatively high affinity for the Ins(1,4,5)P(3)-R but maintains the lowest efficacy of all the partial agonists thus far identified. As such, it may be a useful tool for pharmacological intervention in the polyphosphoinositide pathway and an important lead compound for the development of further Ins(1,4,5)P(3)-R antagonists.

Inositol polyphosphate-mediated iron transport in Pseudomonas aeruginosa

It has previously been shown that myo-inositol hexakisphosphate (myo-InsP6) mediates iron transport into Pseudomonas aeruginosa and overcomes iron-dependent growth inhibition. In this study, the iron transport properties of myo-inositol trisphosphate and tetrakisphosphate regio-isomers were studied. Pseudomonas aeruginosa accumulated iron (III) at similar rates whether complexed with myo-Ins(1,2,3)P3 or myo-InsP6. Iron accumulation from other compounds, notably D/L myo-Ins(1,2,4,5)P4 and another inositol trisphosphate regio-isomer, D-myo-Ins(1,4,5)P3, was dramatically increased. Iron transport profiles from myo-InsP6 into mutants lacking the outer membrane porins oprF, oprD and oprP were similar to the wild-type, indicating that these porins are not involved in the transport process. The rates of reduction of iron (III) to iron (II) complexed to any of the compounds by a Ps. aeruginosa cell lysate were similar, suggesting that a reductive mechanism is not the rate-determining step.

Inositol 1,4,5-trisphosphate receptor subtypes differentially recognize regioisomers of D-myo-inositol 1,4,5-trisphosphate

The Ins(1,4,5)P3 regioisomers, Ins(1,4,6)P3 and Ins(1,3,6)P3, which can mimic the 1,4,5-arrangement on the inositol ring of Ins(1,4,5)P3, were examined for Ca2+ release by using four types of saponin-permeabilized cell possessing various abundances of receptor subtypes, with special reference to the relation of potency to receptor subtype. Ins(1,4,6)P3 and Ins(1,3,6)P3 were weak agonists in rat basophilic leukaemic cells (RBL cells), which possess predominantly subtype II receptors, with respective potencies of 1/200 and less than 1/500 that of Ins(1,4,5)P3 [the EC50 values were 0.2, 45 and more than 100 microM for Ins(1,4,5)P3, Ins(1,4,6)P3 and Ins(1,3,6)P3 respectively]. Similar rank order potencies were also evaluated for the displacement of [3H]Ins(1,4,5)P3 bound to RBL cell membranes by these regioisomers. However, they caused Ca2+ release from GH3 rat pituitary cells possessing predominantly subtype I receptors more potently; Ins(1,4,6)P3 and Ins(1,3,6)P3 evoked release at respective concentrations of only one-third and one-twentieth that of Ins(1,4,5)P3 (the EC50 values were 0.4, 1.2 and 8 microM for Ins(1,4,5)P3, Ins(1,4,6)P3 and Ins(1,3,6)P3 respectively). In COS-1 African green-monkey kidney cells, with the relative abundances of 37% of the subtype II and of 62% of the subtype III receptor, potencies of 1/40 and approx. 1/200 for Ins(1, 4,6)P3 and Ins(1,3,6)P3 respectively were exhibited relative to Ins(1,4,5)P3 (the EC50 values were 0.4, 15 and approx. 80 microM for Ins(1,4,5)P3, Ins(1,4,6)P3 and Ins(1,3,6)P3 respectively). In HL-60 human leukaemic cells, in spite of the dominant presence of subtype I receptors (71%), similar respective potencies to those seen with COS-1 cells were exhibited (the EC50 values were 0.3, 15 and approx. 100 microM for Ins(1,4,5)P3, Ins(1,4,6)P3 and Ins(1,3,6)P3 respectively). These results indicate that these regioisomers are the first ligands that distinguish between receptor subtypes; the present observations are of significance for the future design of molecules with enhanced selectivity.

Endoscopic screening and surgery for familial adenomatous polyposis: dangerous delays

BACKGROUND

Registries for patients with familial adenomatous polyposis (FAP) can improve patient management. However, in relation to colorectal cancer, a critical review has not previously been undertaken of the effectiveness of screening and surgical protocols within a registry.

METHODS

A review was undertaken of 63 gene carriers who received primary treatment for FAP between 1987, when the Northern Region Polyposis Registry was formed, and 1995.

RESULTS

In some gene carriers with colorectal cancer, surgery was delayed because of social factors or unpleasant surgical experiences in the family. Colonoscopy failed to detect five colorectal cancers.

CONCLUSIONS

Delays in treatment still occur in patients with FAP and colorectal cancer, often because of complex social problems and patients' fear of surgery. If multiple colorectal polyps are present, colonoscopy is not a reliable screening test for malignancy and prophylactic surgery is indicated, preferably before the patient is 20 years old.

Enantiomers of myo-inositol-1,3,4-trisphosphate and myo-inositol-1,4,6 -trisphosphate: stereospecific recognition by cerebellar and platelet myo-inositol-1,4,5-trisphosphate receptors

The naturally occurring tetrakisphosphate myo-inositol-1,3,4, 6-tetrakisphosphate [Ins(1,3,4,6)P4] was able to release Ca2+ from the intracellular stores of permeabilized rabbit platelets but was 40-fold less potent than D-myo-inositol-1,4,5-trisphosphate [Ins(1,4,5)P3]. The Ca2+ releasing activity of Ins(1,3,4,6)P4 was rationalized by envisaging two alternative receptor binding orientations in which the vicinal D-1,6-bisphosphate of Ins(1,3,4,6)P4 mimics the D-4,5-bisphosphate in the Ins(1,4,5)P3 binding conformation. This rationalization predicted that Ins(1,4,5)P3 regioisomers [i.e, D-myo-inositol -1,4,6-trisphosphate [D-Ins(1,4,6)P3] and D-myo-inositol-1,3,6 -trisphosphate [D-Ins(1,3,6)P3]] should also possess Ca(2+)-releasing activity. The unambiguous total synthesis of the enatiomers of Ins(1,4,6)P3 [i.e., D-Ins(1,4,6)P3 and D-Ins(3,4,6)P3] and the enatiomers of Ins(1,3,4)P3 [i.e., D-Ins(1,3,6)P3 and D-Ins(1,3,4)P3] allowed an examination of this prediction. D-Ins(1,4,6)P3 released Ca2+ from the intracellular stores of permeabilized platelets and was only 2-3-fold less potent than Ins(1,4,5)P3. D-Ins(1,3,6)P3 [alternative nomenclature, L-Ins(1,3,4)P3] also released Ca2+ but was 12-fold less potent than Ins(1,4,5)P3. Both D-Ins(1,4,6)P3 and D-Ins(1,3,6)P3 displaced specifically bound [3H]Ins(1,4,5)P3 from the Ins(1,4,5)P3 receptor on rat cerebellar membranes. In contrast, however, D-Ins(3,4,6)P3 [alternative nomenclature, L-Ins(1,4,6)P3] and D-Ins(1,3,4)P3 neither possessed Ca(2+)-releasing activity nor displaced [3H]Ins(1,4,5)P3. The ability of D-Ins(1,3,6)P3 to release Ca2+ in permeabilized platelets is in contrast to its apparent lack of Ca(2+)-mobilizing activity previously reported in rat basophilic leukemic cells. The possibility that this is a reflection of the different Ins(1,4,5)P3 receptor subtypes possessed by these two cell types is discussed.

D-myo-inositol 1,4,5-trisphosphate analogues modified at the 3-position inhibit phosphatidylinositol 3-kinase

Several natural and unnatural inositol phosphates and analogues were analyzed for their ability to inhibit the in vitro phosphatidylinositol 3-kinase (PI 3-kinase) activity immunoprecipitated from a leukemic T cell line by a p85 monoclonal antibody. A 3-position ring-modified analogue of D-myo-inositol 1,4,5-trisphosphate (Ins(1,4,5)P3), L-chiro-inositol 2,3,5-trisphosphate (L-chiro-Ins(2,3,5)P3) and its phosphorothioate analogue, L-chiro-inositol 2,3,5-trisphosphorothioate, as well as the analogue benzene 1,2,4-trisphosphate induced reversible inhibition of PI 3-kinase activity, which correlated with decreased Vmax but unchanged Km values for PI 3-kinase. Other inositol phosphates, including D- and L-Ins(1,4,5)P3, D-myo-inositol 1,3,4,5-tetrakisphosphate, the enantiomers of myo-inositol 1,3,4-trisphosphate, DL-myo-inositol 1,4,6-trisphosphate (DL-Ins(1,4,6)P3), and DL-scyllo-inositol 1,2,4-trisphosphate (DL-scyllo-Ins(1,2,4)P3), did not inhibit PI 3-kinase activity under identical conditions. L-chiro-Ins(2,3,5)P3 closely resembles Ins(1,4,5)P3 and D-Ins(1,4,6)P3 except for a difference in the orientation of a single hydroxyl group at either the equivalent 3-OH or 2-OH position of Ins(1,4,5)P3, respectively. Similarly, L-chiro-Ins(2,3,5)P3 resembles D-scyllo-Ins(1,2,4)P3, but has a different orientation of both the equivalent 3-OH and 2-OH positions. Since Ins(1,4,5)P3, DL-Ins(1,4,6)P3, and DL-scyllo-Ins(1,2,4)P3 did not inhibit PI 3-kinase activity, this suggests that the orientation of the two hydroxyl groups at the 2- and 3-positions plays a pivotal role in the inhibitory action of inositol phosphate analogues on PI 3-kinase activity. Thus, inositol phosphate analogues inter alia are shown for the first time to inhibit PI 3-kinase and may be useful tools for determining the function of PI 3-kinase and its substrate binding specificities.

Proliferative compartment deregulation in the non-neoplastic colonic epithelium of familial adenomatous polyposis

Previous work has shown abnormalities in the proliferative activity of the colorectal mucosa in familial adenomatous polyposis (FAP). Some doubts remain about the validity of these findings because of difficulties in excluding adenomatous crypts, particularly in methods using tritiated thymidine, bromodeoxyuridine, and ornithine decarboxylase. The proliferative activity of the epithelium in colonic resections from 20 FAP patients was compared with that of age, sex, and site matched controls using a new monoclonal antibody MIB1 to assay the expression of Ki-67 antigen in routinely processed tissue. The labelling indices were very similar in the polyposis and control cases (25.5 (1.4)% and 26.7 (1.7)% respectively) but analysis of the distribution of labelled cells showed a significant shift of the proliferative compartment towards the luminal surface in the FAP group. Specifically, the labelling index was lower in the basal fifth of the polyposis crypts and higher in the two fifths at the luminal surface. These results show that analysis of proliferative activity in FAP is now achievable in routine histological material and indicate deregulation of proliferative control in the FAP colonic crypt. This may form a useful diagnostic adjunct to standard clinical and molecular genetic techniques, particularly in view of the current interest in dietary and pharmacological intervention in sporadic colorectal carcinoma.

Design of potent and selective inhibitors of myo-inositol 1,4,5-trisphosphate 5-phosphatase

The interactions of synthetic analogues of D-myo-inositol 1,4,5-trisphosphate [Ins(1,4,5)P3] with the Ins(1,4,5)P3 receptor in permeabilized SH-SY5Y cells and with two key metabolic enzymes, Ins(1,4,5)P(3)3-kinase from a supernatant preparation of rat brain homogenates and Ins(1,4,5)P(3)5-phosphatase from human erythrocyte ghosts, have been examined. L-chiro-Inositol 2,3,5-trisphosphorothioate [L-chiro-Ins(2,3,5)PS3], which we have previously identified as a partial agonist at the Ins(1,4,5)P3 receptor [Safrany, S. T., Wilcox, R. A., Liu, C., Dubreuil, D., Potter, B. V. L., & Nahorski S. R. (1993) Mol. Pharmacol. 43, 499-503], is identified as the most potent 5-phosphatase inhibitor yet described (inhibiting dephosphorylation of [3H]Ins(1,4,5)P3 with Ki = 230nM). L-chiro-Ins(2,3,5)PS3 was also found to be the most potent small-molecule inhibitor of 3-kinase (Ki = 820 nM). The properties of three novel, potent, and selective inhibitors of 5-phosphatase are described. L-myo-Inositol 1,4,5-trisphosphorothioate inhibited 5-phosphatase with Ki = 430 nM, showing 250-fold selectivity over 3-kinase (Ki = 108 microM); myo-inositol 1,3,5-trisphosphorothioate inhibited 5-phosphatase with 475-fold selectivity over 3-kinase (Ki = 520 nM and 247 microM, respectively). The most potent, selective inhibitor of 5-phosphatase was L-chiro-inositol 1,4,6-trisphosphorothioate [L-chiro-Ins(1,4,6)PS3]. L-chiro-Ins(1,4,6)PS3 inhibited 5-phosphatase with Ki = 300 nM and did not interact with the Ins(1,4,5)P3 receptor or 3-kinase at doses tested. These studies, therefore, identify a highly potent and selective inhibitor of 5-phosphatase, which should be considered the tool of choice when inhibiting this enzyme in a broken cell or cell-free system.

Modification at C2 of myo-inositol 1,4,5-trisphosphate produces inositol trisphosphates and tetrakisphosphates with potent biological activities

Novel 2-position-modified D-myo-inositol 1,4,5-trisphosphate [Ins(1,4,5)P3] analogues, DL-2-deoxy-2-fluoro-myo-inositol 1,4,5-trisphosphate [DL-2F-Ins(1,4,5)P3], DL-myo-inositol 1,2,4,5-tetrakisphosphate [DL-Ins(1,2,4,5)P4], DL-scyllo-inositol 1,2,4-trisphosphate [DL-sc-Ins(1,2,4)P3], scyllo-inositol 1,2,4,5-tetrakisphosphate [sc-Ins(1,2,4,5)P4] and scyllo-inositol 1,2,4,5-tetrakisphosphorothioate [sc-Ins(1,2,4,5)PS4] were investigated for their ability to bind to the Ins(1,4,5)P3 receptor, mobilise intracellular Ca2+ stores and interact with metabolic enzymes. With the exception of sc-Ins(1,2,4,5)PS4, all the Ins(1,4,5)P3 analogues potently displaced [3H]Ins(1,4,5)P3 from its receptor in bovine adrenal cortex and were apparently potent full agonists at the Ca2+ mobilising Ins(1,4,5)P3 receptor of SH-SY5Y cells, giving respective IC50 and EC50 values of: sc-Ins(1,2,4,5)P4 (IC50 14 nM, EC50 77 nM), DL-2F-Ins(1,4,5)P3 (IC50 25 nM, EC50 105 nM), DL-Ins(1,2,4,5)P4 (IC50 26 nM, EC50 163 nM), DL-sc-Ins(1,2,4)P3 (IC50 52 nM, EC50 171 nM), compared to Ins(1,4,5)P3 (IC50 4 nM, EC50 52 nM). sc-Ins(1,2,4,5)P4 was equipotent to Ins(1,4,5)P3 for Ca2+ release making it the most potent inositol tetrakisphosphate and indeed Ins(1,4,5)P3 analogue yet characterised. In contrast, although sc-Ins(1,2,4,5)P4 (IC50 425 nM, EC50 1603 nM) was a significantly weaker ligand and agonist than Ins(1,4,5)P3, it was a partial agonist of high intrinsic activity with maximally effective concentrations releasing only about 80% of Ins(1,4,5)P3-sensitive Ca2+ stores of SH-SY5Y cells. Ins(1,4,5)P3 and sc-Ins(1,2,4,5)P4 were readily metabolised by Ins(1,4,5)P3 3-kinase and 5-phosphatase activities, DL-2F-Ins(1,4,5)P3 and DL-sc-Ins(1,2,4)P3 were resistant to 5-phosphatase, while sc-Ins(1,2,4,5)PS4 and DL-Ins(1,2,4,5)P4 were resistant to both 3-kinase and 5-phosphatase activity and were potent inhibitors of the 5-phosphatase enzyme (Ki = 300 nM and 2.9 microM, respectively). These results demonstrate that modification of the 2-position of Ins(1,4,5)P3, even with an anionic group, does not critically affect Ins(1,4,5)P3 binding interaction or Ca2+ release, suggesting that the 2-OH of Ins(1,4,5)P3 fails to interact significantly with the binding site of its receptor. However, modification remote from the crucial vicinal 4,5-bisphosphate can affect analogue efficacy in Ca2+ release.

Screening for bacteriuria in urological patients using reagent strips

A rapid and accurate ward-based method of diagnosing urinary infection would be of value in determining the prescription of antibiotics in pre-operative urological patients. This study describes the sensitivity and specificity of a screening technique based on commercially available reagent strips in the diagnosis of urinary infection. A total of 222 pre-operative samples and 83 post-operative samples was studied to compare the results of formal urine culture and reagent strips. Using a definition of a positive nitrite or a positive leucocyte esterase on the reagent strips as being suggestive of infection, it was found that the strips had a sensitivity of 91% and a specificity of 85% compared with formal culture in pre-operative samples. The results from post-operative samples were less satisfactory, the strips having a sensitivity of only 71% and specificity of 55%. The strips were insensitive but specific in the identification of pyuria in pre-operative specimens. These results suggest that reagent strips can be used as a ward-based method to identify men at risk of infection before urological procedures, and may allow selectivity in the use of peri-operative antibiotics.

Integral excitation functions for natKr + p up to 116 MeV and optimization of the production of 81Rb for (81m)Kr generators

Effective cross-sections for the production of 79,81,81m,82m,83,84,84m,86Rb, (77,79,85m)Kr and 77,82Br in the bombardment of natKr with protons were measured from threshold up to 116 MeV. Thick-target production-rate curves based on the measured integral excitation functions were also derived for 81,82m,83,84,86Rb, and the optimum incident energy for the production of 81Rb/(81m)Kr, as a function of the target thickness in MeV, was determined. Geometry-dependent hybrid-model calculations performed by means of the computer code ALICE/85/300 were found to be in good agreement with the experimental results as well as the derived thick-target production-rate curves.

Production of 52Fe via proton-induced reactions on manganese and nickel

Excitation functions for the production of 52Fe in the bombardment of Mn and Ni with protons were measured from threshold up to 200 MeV. Production rates of 52Fe as well as of its 55Fe and 59Fe impurities were also measured in specific energy windows ranging up to 100 MeV. The agreement with previous measurements, where available, is reasonably good, except that considerably higher 55Fe contamination levels than those recently reported below 70 MeV were obtained in the case of Ni. The experimental results were compared with theoretical calculations by means of the computer code ALICE/85/300. Overall agreement to within a factor of two was obtained, and the usefulness of the code in planning a radioisotope production process was demonstrated. Finally, practical production rates and impurity levels, obtained with a 66 MeV proton beam at high intensities (approximately 50 microA), are reported.