Use of a modified Delphi approach to develop research priorities for the association of coloproctology of Great Britain and Ireland

AIM

The modified Delphi approach is an established method for reaching a consensus opinion among a group of experts in a particular field. We have used this technique to survey the entire membership of the Association of Coloproctology of Great Britain and Ireland (ACPGBI) to reach a consensus on prioritizing clinical research questions in colorectal disease.

METHOD

Three rounds of surveys were conducted using a web-based tool. In the first, the ACPGBI membership was invited to submit research questions. In Rounds 2 and 3 they were asked to score questions on priority. A steering group analysed the results of each round to identify those questions ranked as being of highest priority.

RESULTS

Five hundred and two questions were submitted in Round 1. Following two rounds of voting and analysis, a list of 25 priority questions was produced, including 15 cancer-related and 10 noncancer-related questions.

CONCLUSION

It is anticipated that these results will: (i) set the research agenda over the next few years for the study of colorectal disease in the United Kingdom, (ii) promote development and (iii) define funding of new research and prioritize areas of unmet clinical need where the potential clinical impact is greatest.

Chemoradiation for the treatment of epidermoid anal cancer: 13-year follow-up of the first randomised UKCCCR Anal Cancer Trial (ACT I)

Background:

The first UKCCCR Anal Cancer Trial (1996) demonstrated the benefit of chemoradiation over radiotherapy (RT) alone for treating epidermoid anal cancer, and it became the standard treatment. Patients in this trial have now been followed up for a median of 13 years.

Methods:

A total of 577 patients were randomised to receive RT alone or combined modality therapy using 5-fluorouracil and mitomycin C. All patients were scheduled to receive 45 Gy by external beam irradiation. Patients who responded to treatment were recommended to have boost RT, with either an iridium implant or external beam irradiation. Data on relapse and deaths were obtained until October 2007.

Results:

Twelve years after treatment, for every 100 patients treated with chemoradiation, there are an expected 25.3 fewer patients with locoregional relapse (95% confidence interval (CI): 17.5–32.0 fewer) and 12.5 fewer anal cancer deaths (95% CI: 4.3–19.7 fewer), compared with 100 patients given RT alone. There was a 9.1% increase in non-anal cancer deaths in the first 5 years of chemoradiation (95% CI +3.6 to +14.6), which disappeared by 10 years.

Conclusions:

The clear benefit of chemoradiation outweighs an early excess risk of non-anal cancer deaths, and can still be seen 12 years after treatment. Only 11 patients suffered a locoregional relapse as a first event after 5 years, which may influence the choice of end points in future studies.

A randomized trial of chemoradiation using mitomycin or cisplatin, with or without maintenance cisplatin/5FU in squamous cell carcinoma of the anus (ACT II)

LBA4009

Background: Chemoradiotherapy (CRT) with 5-fluorouracil (5-FU) and mitomycin-C (MMC) is standard treatment for anal cancer. This trial addresses two questions: whether (i) replacing MMC with cisplatin (CDDP) improves the complete response (CR) rate, and (ii) two cycles of maintenance chemotherapy after CRT reduces recurrence. Methods: Between 2001 and 2008, 940 patients (pts) were recruited to a multicenter, randomized factorial trial. Pts received 5-FU (1,000mg/m2/day on d1–4 and 29–32), radiotherapy (RT) (50.4Gy in 28 fractions), and either MMC (12mg/m2, d1; n=471) or CDDP (60mg/m2 on d1 and 29; n=469). Pts were also randomized to receive maintenance therapy (n=448) 4 weeks after CRT (two cycles of CDDP and 5-FU weeks 11 and 14) or no maintenance (n=446). Maintenance randomization was not considered appropriate in 46 pts. Statistical power was ≥80% to detect a difference in the CR rate of 5% (CDDP vs MMC), and 30% reduction in recurrence (maintenance vs no maintenance). Results: Median age 58 yrs; 62% male, 38% female; tumor site - canal (81%), margin (15%); stage T1-T2 (50%), T3-T4 (43%); node negative (62%), positive (30%). Median follow-up was 3 yrs. The CR rate was 94% MMC and 95% CDDP (p=0.53). MMC pts had more acute grade 3/4 haematological toxicities (25 vs 13%, p<0.001) but this did not result in an increase in neutropaenic sepsis (3.1 vs 3.2%, p=0.93). Non-haematologic grade 3/4 toxicities were similar (61 vs 65%, p=0.22). Preliminary analysis shows no statistically significant difference in recurrence free survival (RFS) (HR 0.89, 95% CI 0.68, 1.18; p=0.42) or overall survival (HR 0.79, 95% CI 0.56,1.12; p=0.19) for the maintenance comparison. The number of pre-treatment colostomies not reversed were similar between treatments (18 MMC vs 14 CDDP, p=0.65, Maint/No maint, p=0.23) and only 9 disease-free pts had colostomies performed (5 MMC, 4 CDDP). Conclusions: ACT II is the largest trial conducted in anal cancer. High CR (95%) and RFS (75% at 3 yrs) rates were achieved with this CRT. This excellent outcome may have been influenced by the absence of a gap in the RT schedule. There was no difference in CR rates between MMC and CDDP or in RFS rates with or without maintenance chemotherapy. 5-FU, MMC with RT remains the standard of care.

[Table: see text]

A randomized trial of chemoradiation using mitomycin or cisplatin, with or without maintenance cisplatin/5FU in squamous cell carcinoma of the anus (ACT II)

LBA4009

The full, final text of this abstract will be available in Part II of the 2009 ASCO Annual Meeting Proceedings, distributed onsite at the Meeting on May 30, 2009, and as a supplement to the June 20, 2009, issue of the Journal of Clinical Oncology.

[Table: see text]

The effect of surgically induced ischaemia on gene expression in a colorectal cancer xenograft model

Delays in tissue fixation following tumour vascular clamping and extirpation may adversely affect subsequent protein and mRNA analysis. This study investigated the effect of surgically induced ischaemia in a xenograft model of a colorectal cancer on the expression of a range of prognostic, predictive, and hypoxic markers, with a particular emphasis on thymidylate synthase. Vascular occlusion of human tumour xenografts by D-shaped metal clamps permitted defined periods of tumour ischaemia. Alterations in protein expression were measured by immunohistochemistry and spectral imaging, and changes in mRNA were measured by reverse transcriptase–polymerase chain reaction. Thymidylate synthase expression decreased following vascular occlusion, and this correlated with cyclin A expression. A similar reduction in dihydropyrimidine dehydrogenase was also seen. There were significant changes in the expression of several hypoxic markers, with carbonic anhydrase-9 showing the greatest response. Gene transcriptional levels were also noted to change following tumour clamping. In this xenograft model, surgically induced tumour ischaemia considerably altered the gene expression profiles of several prognostic and hypoxic markers, suggesting that the degree of tumour ischaemia should be minimised prior to tissue fixation.

Predictors of attendance in the United Kingdom flexible sigmoidoscopy screening trial

OBJECTIVE

To investigate predictors of attendance in the United Kingdom flexible sigmoidoscopy screening trial.

DESIGN

Prospective design in which participants completed a postal questionnaire before being sent their invitation for screening.

SETTING

Welwyn Garden City and Leicester, United Kingdom.

PARTICIPANTS

A total of 2758 patients aged 55 to 64, registered with general practices in the two centres, who (a) expressed interest in having the screening test, (b) completed a postal questionnaire, and (c) were subsequently invited for screening.

MAIN RESULTS

The attendance rate among questionnaire responders was 76.1%. Multiple logistic regression analysis yielded a final model that included nine independent predictors of attendance. Patients with the following characteristics were more likely to attend: men; home owners; non-smokers; those who had regular check ups at the dentist; those with better subjective health; those who minded less about having medical tests; those who said they would definitely rather than probably take up the offer of sigmoidoscopy screening; and those who perceived less barriers and more benefits to having the test.

CONCLUSIONS

The findings are broadly consistent with previous studies of screening participation, although subjective health emerged as an important predictor in this study. There was no evidence for "reverse targeting": attenders were not at lower (or higher) risk for colorectal cancer compared with non-attenders. The findings relating to attitudes and beliefs could be used in efforts to improve attendance, for example by developing information leaflets that address barriers to screening. Other findings could be used to target interventions to subgroups that have relatively low rates of screening participation.

Surgery for colorectal cancer in elderly patients: a systematic review. Colorectal Cancer Collaborative Group

BACKGROUND

The effectiveness of surgery for colorectal cancer depends on it being carried out safely, which allows most patients to return to productive lives, with an improved postoperative life expectancy, or at least one that is not diminished by the surgery. Because colorectal cancer is a major cause of morbidity and mortality in elderly people, we have examined how the outcomes of surgery in elderly patients differ from those in younger patients.

METHODS

We did a systematic review of published and aggregate data provided by investigators. Studies were identified by computerised and manual searches of published and unpublished reports, scanning references, and contacting investigators. Within each study, outcomes for patients aged 65-74 years, 75-84 years, and 85+ years were expressed in relation to those aged less than 65 years.

FINDINGS

From 28 independent studies, and a total of 34,194 patients, we found that elderly patients had an increased frequency of comorbid conditions, were more likely to present with later-stage disease and undergo emergency surgery, and less likely to have curative surgery than younger patients. The incidence of postoperative morbidity and mortality increased progressively with advancing age. Overall survival was reduced in elderly patients, but for cancer specific survival age-related differences were much less striking.

INTERPRETATION

The relation between age and outcomes from colorectal cancer surgery is complex and may be confounded by differences in stage at presentation, tumour site, pre-existing comorbidities, and type of treatment received. However, selected elderly patients benefit from surgery since a large proportion survive for 2 or more years, irrespective of their age.

Which type of follow-up?

Most patients and many surgeons assume that proactive follow-up after rectal cancer surgery is useful in most cases and therefore an essential part of surgical care. The evidence base for this contention is sparse. What evidence there is suggests that there is little effect on the supervivability of recurrent cancer however intense, costly--or the opposite--the follow-up program may be. This review examines some of the issues in this difficult area, and suggests some reasonable conclusions on what degree of follow-up might be applied in the absence of a wide and easily applicable evidence base.

Dynamics of Ascospore Release by Apiosporina morbosa from Sour Cherry Black Knots

Ascospore discharge was monitored from black knots excised from sour cherry trees in May 1992 and 1993, and March, April, and May 1994 and 1995. Rain, temperature, and wetness duration were monitored and a regression model was developed to describe the relationship between environmental conditions and ascospore discharge. Regardless of the date of excision, the peak period for ascospore release occurred from late May (shuck split) through the end of June (shoots 20 cm long), considerably later than previously reported from knots on plum. Fewer ascospores were released from knots excised in early March compared to later dates in 1994. In 1995, the spring was much warmer than in 1994 and ascospore release from March-excised knots was comparable to that from knots excised later in the spring. The period of release and total number of ascospores released was similar from non-excised knots and from knots excised in April or May 1994. Release of ascospores was dependent on rainfall and temperature, but not on the duration of wetness.

Response to 5-fluorouracil of orthotopically xenografted human colon cancers with a microsatellite instability: influence of P53 status

Response to 5-FU of 5 different human colon cancers (hCC) with a DNA microsatellite instability (MSI), xenografted into nude mice, was analysed according to their p53 status. Two hCC (TC82 and TC71) had a mutated p53 (mutp53), while two others (TC33 and LoVo) had a wild type p53 (wtp53); the fifth tumour (X17LoVo) originated from the stable transfection of LoVo cells with a dominant mutp53 (273his) vector. All tumours were implanted onto the caecum of nude mice to induce orthotopic growth of hCC. 5-FU was administered at 40 mg/kg per day for 5 consecutive days. A significant growth inhibition of TC82 and TC71 tumours (of 68 and 60%, p < 0.05 and < 0.01 respectively) was observed, whereas 5-FU had no effect on TC33 and LoVo. Moreover, the mutp53 transfected tumour, X17LoVo, displayed significant sensitivity to 5-FU (p < 0.05). This suggests that distinct genetic alterations influence differently the response of hCC to this antimetabolite.

Inherited susceptibility to colorectal adenomas and carcinomas: evidence for a new predisposition gene on 15q14-q22

BACKGROUND & AIMS

The aim of this study was to evaluate the role of known colorectal adenoma and carcinoma susceptibility genes and to locate a novel susceptibility gene in an Ashkenazi family (SM1311) with dominantly inherited predisposition to colorectal adenomas and carcinomas.

METHODS

Clinicopathologic and family history data were collected. Genetic linkage and mutational analyses were used to investigate the genetic basis of the family's disease.

RESULTS

Affected members of SM1311 develop multiple tubular, villous, tubulovillous, and/or serrated colorectal adenomas throughout the large bowel, and some develop colon carcinoma. There are no extracolonic features clearly associated with disease in SM1311. We have shown that the family's phenotype does not result from APC mutations (including the I1307K variant) or from genetic changes in the other known genes that predispose to colon cancer. Using genetic linkage analysis, supplemented by allele loss in tumors, we have provided evidence for a new colorectal cancer susceptibility gene, CRAC1 (colorectal adenoma and carcinoma), mapping to chromosome 15q14-q22.

CONCLUSIONS

We provide evidence for a novel colorectal adenoma and carcinoma susceptibility gene on chromosome 15q14-q22. Further studies are needed to confirm this localization and to evaluate the contribution of CRAC1 to this disease.

[Value of human colonic cancer models by surgical cecal implantation in nude mice]

A better understanding of the nature and treatment of colon cancer, and of by metastatic dissemination should be achieved by the use and study of appropriate animal models. Such models can be created by grafting human cancer cells or tumour fragments orthotopically into the colon or caecum of nude mice. This review examines the rationale behind these models and the principal results of orthotopic transplantation. Despite the fact that they require surgical expertise and are time-consuming, they provide valuable information on the mechanism of metastasis and the efficacy of novel treatments.

Vaginal endosonography to diagnose enterocoele

Radiological diagnosis of enterocoele is possible using evacuation proctography, but the standard technique must be modified to reveal the small bowel. Since prolapsed bowel is interposed between the vagina and rectum, diagnosis may be possible using vaginal endosonography. We describe a simple ultrasound technique to diagnose enterocoele, which has been validated by comparison with proctography. 17 women were examined with vaginal endosonography, and a diagnosis of enterocoele made if bowel was visualized in the rectovaginal space when bearing down. The findings were compared with subsequent proctography. In eight cases (47%) bowel prolapsed into the rectogenital space during straining, obscuring the rectum, while this did not occur in the remaining nine subjects (53%). Proctography confirmed an enterocoele in six of the eight cases in whom it had been diagnosed on endosonography, and confirmed the absence of enterocoele in all of the nine cases negative on endosonography. These values gave vaginal endosonography a sensitivity of 100% and specificity of 82%, with a positive predictive value of 75%, and negative predictive value of 100% for a prevalence of abnormality of 0.35. Vaginal endosonography is a quick, easy and convenient alternative to evacuation proctography for the radiological diagnosis of enterocoele.

The use of prognostic markers in surgery for colorectal cancer

The basis for prognostic prediction after surgery for colorectal cancer remains the various pathological staging systems based on that of Dukes. Serum prognostic markers have not shown significant independent prognostic power compared with these predictive tools. Much energy has been expended in examining the ability of serum markers to predict recurrent tumour prior to the onset of symptoms. Carcinoembryonic antigen (CEA) has been a particular subject of attention, and has been widely, though variably, advocated as a useful predictor in these circumstances. It has been estimated that around half a million Americans are presently undergoing regular postoperative CEA monitoring to this end. Controversy continues regarding the therapeutic utility of such monitoring. This may be resolved when the results of the only randomised trial in the field are published in the near future. No other serum marker, nor any combination of markers, has been shown clearly to be superior to CEA as a predictor of recurrent tumour.

Level of expression of E-cadherin mRNA in colorectal cancer correlates with clinical outcome

A series of colorectal carcinomas (n = 49) resected from patients with known clinical outcomes were analysed for E-cadherin expression using in situ hybridisation to measure mRNA. Patients surviving 5 years or longer (n = 31) exhibited significantly higher levels of E-cadherin mRNA than those surviving less than 5 years (n = 18, P = 0.003). These preliminary results from this small sample suggest that E-cadherin expression may be a useful prognostic marker in colorectal cancer patients.

Immunolocalization of criptoregulin and amphiregulin in rectal-cancer - correlation with prognosis

We have examined the expression of two newly identified members of the EGF family, cripto and amphiregulin (AR), in a series of 58 primary rectal carcinomas and adjacent non-involved mucosa by immunohistochemical staining using rabbit polyclonal antibodies. More than 90% (53/58) of rectal carcinomas showed AR immunoreactivity whereas cripto was found in 41 out of 58 (71%) tumours. Cripto immunoreactivity was most frequently seen in tumours arising in the lower third of the rectum (p<0.01) and in flat and excavated lesions (p<0.05). Out of 54 normal rectal mucosae adjacent to carcinoma 20 (37%) showed cripto immunoreactivity and all showed a trend towards a higher recurrence rate. Ten of these 20 (50%) rectal tumours showed less cripto immuno-reactivity than the adjacent normal mucosa and were penetrating through the bowel wall and recurred within 5 years. There was a correlation between increased cripto immunoreactivity in the normal mucosa and lymph node involvement (p=0.01). AR immunoreactivity was present in the majority (52/58, 94%) of the normal mucosae adjacent to tumours. No correlation was found between AR immunostaining, histology and prognosis.

A comparison between cytology and histology to detect anal intraepithelial neoplasia

INTRODUCTION

Anal intraepithelial neoplasia (AIN), which may be a precursor of anal carcinoma, has been identified on histology following minor anal surgical procedures, in particular the removal of perianal condylomata, in increasing numbers of homosexual and bisexual men. Anal cytology has recently been proposed as a useful method of identifying AIN lesions.

OBJECTIVE

To compare anal cytology with histology as a method of detecting AIN.

METHODS

215 homosexual and bisexual men attending a central London sexually transmitted diseases clinic had an anal cytological smear performed under standard conditions. The perianal area and anal canal were then examined using a colposcope, and areas macroscopically suggestive of intraepithelial neoplasia were biopsied.

RESULTS

176 of the 215 patients were biopsied of whom 76 had AIN on histology. 154 of the 215 patients had an adequate anal smear of whom 46 and 85 had cytological features of both HPV and AIN, or HPV alone respectively. Including features of HPV alone as an abnormal smear, anal cytology, when compared with anoscopy and histology as the gold standard for diagnosing AIN, resulted in a sensitivity of 87.5%, a specificity of 16.3%, a positive predictive value of 37.4% and a negative predictive value of 69.6%. Restricting abnormal smears to those with features of both HPV and AIN resulted in a sensitivity of 33.9%, a specificity of 72.5%, a positive predictive value of 41.3% and a negative predictive value of 65.7%.

CONCLUSION

Anal cytology is a sensitive but nonspecific method of identifying patients with biopsy proven AIN if cytological features of HPV alone are included as abnormal smears. Specificity is improved by restricting abnormal smears to those with features of both HPV and AIN but this markedly lowers the sensitivity of the test. At present, anoscopy and histology are required in addition to anal cytology to differentiate between patients who simply have anal condylomata and those who also have AIN.

Self-administered faecal occult blood tests do not increase compliance with screening for colorectal cancer: results of a randomized controlled trial

In the UK, compliance with conventional faecal occult blood (FOB) tests such as Haemoccult is about 50% in the general population. It has been postulated that characteristics of the performance of conventional tests, in particular the need for dextrous gathering and manipulation of faeces, delay in receiving results, and the recommended dietary restrictions, may all diminish compliance. New FOB tests have been developed, popularly termed 'magic toilet paper' tests, which not only minimize faecal manipulation but are also self-reported. Compliance rates with two self-administered faecal occult blood tests (Early Detector and Coloscreen Self-Test) were compared with Haemoccult in a randomized trial involving 1,842 subjects aged 40-74 years. Use of self-administered FOB tests did not increase compliance significantly, with rates of 52.1% for Early Detector, 50.6% for Coloscreen and 49.1% for Haemoccult. Moreover, dietary restriction did not reduce compliance significantly (restricted 49.3%, unrestricted 51.8%). A wide variation (from 1.3% to 21.4%) in positivity rates was observed which was dependent on which of the three tests was used and whether dietary restrictions were applied. Since the physical aspects of test performance do not appear to determine an individual's decision to be screened, self-administered tests will not overcome the problem of poor compliance with FOB screening.

The establishment of a polyposis register

Guidelines are presented for the establishment of a regional or national register of patients with familial adenomatous polyposis. The detailed recommendations are based on the work in committees of the "Leeds Castle Polyposis Group" and the "EuroFAP". The aims of national and regional polyposis registers are discussed, and the stages of development of a register are reviewed: Ascertainment of probands, construction of pedigrees, identification of family members at risk, and screening of members at risk. The problem of data confidentiality is discussed.

Patient compliance with colorectal cancer screening in general practice

A randomized controlled trial to test patient compliance with screening for colorectal cancer in association with general practice health checks was carried out in six practices (three urban and three rural). A total of 1588 patients aged 45-64 years were randomized to one of four intervention groups. In the first group patients were posted a Haemoccult test (Kline Beckman) kit. This group was not invited for a health check. In the second group patients were posted the Haemoccult test kit, together with an invitation to attend for a health check. In the third group patients were posted an invitation for a health check, which explained that the patient would be offered the Haemoccult test kit by the nurse at the health check. In the fourth group patients were just invited for a health check. It was found that combining faecal occult blood testing with the health check did not reduce attendance at the health check--43.5% of patients attended when the Haemoccult test kit was offered by the nurse at the health check, 43.6% attended when a test kit was included with the invitation to attend the health check and 42.9% attended when the health check invitation was posted on its own. Overall, compliance with Haemoccult testing was not significantly increased by associating it with a health check (26.2% versus 25.5%) but compliance was higher when the faecal occult blood testing kit was enclosed with the health check invitation than when it was offered at the health check (31.7% versus 20.6%, P less than 0.001). It is easier and cheaper to combine various screening procedures. Although the overall use of the Haemoccult test in the study population was low, there is no reason why the relatively higher compliance rate obtained on posting the test kit with a health check invitation cannot be achieved in previously unscreened populations with higher expected compliance rates. However, faecal occult blood screening for colorectal cancer should not be undertaken on a population basis until its effectiveness in reducing mortality has been proven by randomized trial.

The effect of self-administered faecal occult blood tests on compliance with screening for colorectal cancer: results of a survey of those invited

To determine the relative importance of health beliefs and the characteristics of different methods of faecal occult blood screening in predicting acceptance of the test a self completed questionnaire was offered to 590 patients registered with a practice in an Oxfordshire market town. The patients were an age-sex stratified random sample of those who had been offered screening as part of a trial in which one of three different faecal occult blood screening tests, two of which were self-reported, had been offered. The overall adjusted response rate was 70.1%. Those who complied with the test had more positive attitudes to the implications of a positive test, to treatment and to the value of screening in general. The experience of a close relative or friend with bowel cancer was associated with an increased likelihood of compliance [odds ratio = 15.2 (9.4-24.3)]. Three were marked differences between the tests in the proportions of patients finding them 'messy' or 'disgusting' (Haemoccult 72.0%, Coloscreen 48.0%, Early Detector 55.4% chi 2 Haemoccult vs. self-reported = 5.05 P less than 0.05), and the odds of finding the procedure disgusting were significantly higher among patients who did not complete the test [odds ratio 6.9 (3.1-15.5)].

Post-myelogram headache--physiological or psychological?

Psychological aspects of post-lumbar puncture headache have hitherto received little attention. A hundred consecutive patients admitted for elective myelography were studied. Post-myelogram headache was assessed by an independent observer and found to be strongly associated with normality of the test (P less than 0.001). Psychological testing showed a trend between Hospital Anxiety Depression score and normality of myelogram as well as development of headache, although this did not achieve statistical significance. This study suggested that there is a large psychological as well as organic component to post-myelogram headache.

Experiences of patients with false positive results from colorectal cancer screening

A survey was conducted to study the experiences of patients with false positive results for colorectal cancer. The study patients were participants in a randomized trial of compliance with different methods of colorectal cancer screening by faecal occult blood testing. Fifty four out of fifty six patients (96.4%) with false positive results agreed to be interviewed. An age and sex matched control group of 112 patients with negative test results was identified --92 (82.1%) returned questionnaires. Thirteen of the patients with false positive results (24.1%) and 19 controls (20.7%) were to some extent distressed by the initial letter inviting them to participate in the screening programme. Thirty seven of the patients with false positive results (68.5%) felt some degree of distress at the initial positive test result and 19 (35.2%) some distress because of delays experienced in the process of being screened. Ten false positive patients had colonoscopy and the median waiting time for this procedure was 10 days--half of the patients found this wait distressing. Nevertheless, 53 of the patients with false positive results (98.1%) felt that it had been worthwhile to have had the test. Generally, colorectal screening was as acceptable to the patients who experienced false positive results as to those with negative results.

Formation of the primary protective layer and phellogen after leaf abscission in peach

Potted peach trees (Prunus persica (L.) Batsch cv. Loring) were mechanically defoliated and the influence of temperature on formation of the primary protective layer and phellogen generation in the leaf abscission region was examined histologically. Plants maintained at 7.5, 12.5, and 17.5 °C showed first indications of primary protective layer formation at 18, 9, and 6 days, respectively. Subsequent generation of phellogen and the appearance of the first phellem cell were observed at 30, 18, and 12 days, respectively. The primary protective layer formed approximately 700 μm proximal to the separation zone and was composed of cells with lignified walls and thin suberin linings.

Effect of catheter tunnelling and a nutrition nurse on catheter sepsis during parenteral nutrition. A controlled trial

In a three-year controlled trial of subcutaneous catheter tunnelling as a method of reducing total parenteral nutrition (TPN) catheter sepsis 99 silicone catheters (52 tunnelled, 47 untunnelled) were inserted into the subclavian (94%) or jugular (6%) veins under aseptic conditions. The influence of a nutrition nurse, who joined the nutrition team after 18 months, on catheter sepsis rate was also documented. Catheter sepsis was confirmed in 13 of 47 (28%) untunnelled catheters and only 6 of 52 (11.5%) tunnelled catheters (p less than 0.05). A nutrition nurse reduced sepsis rate from 33% (tunnelled 6, untunnelled 11) to 4% (0 tunnelled; 2 untunnelled) (p less than 0.001). There was no significant difference between tunnelled and untunnelled catheters in sepsis rates after the arrival of the nutrition nurse. Although 85% patients had concurrent internal sepsis, the pathogens implicated in catheter sepsis came from superficial sites in 16 of 19 cases (p less than 0.01). Rigorous aseptic nursing care is thus the most significant factor in the reduction of TPN catheter sepsis, but tunnelling can reduce sepsis rate when nursing care is suboptimum.