Evaluation of a quality improvement intervention to reduce anastomotic leak following right colectomy (EAGLE): pragmatic, batched stepped-wedge, cluster-randomized trial in 64 countries

BACKGROUND

Anastomotic leak affects 8 per cent of patients after right colectomy with a 10-fold increased risk of postoperative death. The EAGLE study aimed to develop and test whether an international, standardized quality improvement intervention could reduce anastomotic leaks.

METHODS

The internationally intended protocol, iteratively co-developed by a multistage Delphi process, comprised an online educational module introducing risk stratification, an intraoperative checklist, and harmonized surgical techniques. Clusters (hospital teams) were randomized to one of three arms with varied sequences of intervention/data collection by a derived stepped-wedge batch design (at least 18 hospital teams per batch). Patients were blinded to the study allocation. Low- and middle-income country enrolment was encouraged. The primary outcome (assessed by intention to treat) was anastomotic leak rate, and subgroup analyses by module completion (at least 80 per cent of surgeons, high engagement; less than 50 per cent, low engagement) were preplanned.

RESULTS

A total 355 hospital teams registered, with 332 from 64 countries (39.2 per cent low and middle income) included in the final analysis. The online modules were completed by half of the surgeons (2143 of 4411). The primary analysis included 3039 of the 3268 patients recruited (206 patients had no anastomosis and 23 were lost to follow-up), with anastomotic leaks arising before and after the intervention in 10.1 and 9.6 per cent respectively (adjusted OR 0.87, 95 per cent c.i. 0.59 to 1.30; P = 0.498). The proportion of surgeons completing the educational modules was an influence: the leak rate decreased from 12.2 per cent (61 of 500) before intervention to 5.1 per cent (24 of 473) after intervention in high-engagement centres (adjusted OR 0.36, 0.20 to 0.64; P < 0.001), but this was not observed in low-engagement hospitals (8.3 per cent (59 of 714) and 13.8 per cent (61 of 443) respectively; adjusted OR 2.09, 1.31 to 3.31).

CONCLUSION

Completion of globally available digital training by engaged teams can alter anastomotic leak rates. Registration number: NCT04270721 (http://www.clinicaltrials.gov).

The protective role of phosphodiesterase inhibitors in preventing colorectal cancer and advanced colorectal polyps: a systematic review and meta-analysis

AIM

Inflammatory cells within the tumour microenvironment are the driving forces behind colorectal cancer (CRC) tumourigenesis. Understanding the different pathways involved in CRC carcinogenesis paves the way for effective repurposing of drugs for cancer prevention. Emerging data from preclinical and clinical studies suggest that, due to their antiproliferative and anti-inflammatory properties, phosphodiesterase-5 inhibitors (PDE5i) might have an anticancer effect. The aim of this study was to clarify through systematic review and meta-analysis of published peer-reviewed studies whether an association exists between PDE5i use and CRC risk.

METHOD

This study was guided by the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. Prospective registration was performed on PROSPERO (CRD42022372925). A systematic review was performed for studies reporting CRC and advanced colorectal polyp incidence in PDE5i 'ever-users' and PDE5i 'never-users'. Meta-analysis was performed using RevMan version 5.

RESULTS

Four observational cohort studies and two case-control studies, comprising 995 242 patients were included in the final analysis, of whom 347 126 were PDE5i ever-users. Patients who were PDE5i ever-users had a significantly lower incidence of CRC or advanced colorectal polyps than never-users (OR 0.88, CI 0.79-0.98, p = 0.02). To examine the primary preventative role of PDE5i, subgroup analysis of four studies including patients without a previous history of CRC found that use of PDE5i was associated with a lower incidence of CRC (OR 0.85, CI 0.75-0.95, p = 0.005, I2  = 64%). There was no significant temporal relationship found between PDE5i use and CRC risk as both current users and previous users had a significantly lower incidence of CRC than never-users.

CONCLUSION

Our study found a significant anticancer effect of PDE5i, as shown by a reduced risk of CRC in the context of both primary and secondary CRC prevention.

Beclometasone inhaler-induced recovery of refractory peri-ileostomy skin complications

Peristomal skin complications (PSCs) are relatively common in ostomy patients, particularly in those with ileostomies. Non-healing irritation presents a clinical challenge and leads to pain and impaired quality of life for patients.

METHODS

The cases of four ileostomy patients experiencing severe, challenging PSCs refractory to appliance changes, conventional dressings and barrier creams are discussed.

FINDINGS

The cases of one male and one female patient with an end ileostomy post-subtotal colectomy for ulcerative colitis, one female with a defunctioning ileostomy post-anterior resection for sigmoid carcinoma and one male with an end ileostomy with a complex Crohn's surgical history are described. Two puffs of a 250 mcg metered dose beclometasone inhaler were applied to the affected skin once or twice daily. Treatment ranged from 6 to 21 days. Complete resolution was seen in all cases.

CONCLUSION

Topical use of a beclometasone inhaler was effective for severe peri-ileostomy PSC secondary to four different aetiologies. Further studies are warranted to determine the effectiveness of this treatment in a larger patient cohort.

Outcomes After Colonic Self-Expanding Metal Stent Insertion Without Fluoroscopy: A Surgeon-Led 10-Year Experience

INTRODUCTION

Colonic self-expanding metal stents (SEMS) can be used to relieve malignant and benign large bowel obstruction (LBO) as a bridge to surgery (BTS) and for palliation. Guidelines suggest the use of fluoroscopic guidance for deployment. This may be difficult to obtain after hours and in certain centers. We aimed to determine the outcomes of stenting under endoscopic guidance alone.

METHODS

All patients who underwent SEMS insertion in our tertiary referral center between August 2010 and June 2021 were identified from a prospectively maintained database. Patient demographics (age/gender), disease characteristics (benign versus malignant/location/stage), stenting intent (BTS versus palliative), and outcomes (technical success/stoma/time from stenting to resection/death/study end) were analyzed.

RESULTS

Fifty-three (n = 39, 73.6% male) patients underwent SEMS insertion. Indications included colorectal carcinoma (n = 48, 90.6%), diverticular stricture (n = 3), and gynecological malignancy (n = 2). In five (9.4%) patients (four BTS and one palliative), SEMSs deployment was not completed because of the inability to pass the guidewire. All underwent emergency surgery. In the BTS cohort (n = 29, median 70.4 [range 40.3-91.8] years), 10 patients underwent neoadjuvant chemoradiotherapy. The permanent stoma rate was 20.7% (n = 6). There was no 30- or 90-d mortality. In the palliative cohort (n = 24, median age 77.1 [range 54.4-91.9]), 16 (66.7%) were deceased at the study end. The median time from stenting to death was 5.2 (2.3-7.9) months.

CONCLUSIONS

SEMS placed under endoscopic visualization alone, palliatively and as a BTS, had acceptable stoma, morbidity, and mortality rates. These results show that SEMS insertion can be safely performed without fluoroscopy.

A fundamental change emerging in locally advanced rectal cancer management: a case report

Treatment of locally advanced rectal cancer remains a challenge in colorectal surgery. It has had an evolving landscape over the past three decades. Implementation of total neoadjuvant therapy (TNT) as a novel approach to management has begun globally but long-term outcomes and data analysis to identify optimal schedules are eagerly awaited. We report a case of locally advanced rectal cancer management in a young male with a complete pathological response to TNT.

Prophylactic negative wound therapy in laparotomy wounds (PROPEL trial): randomized controlled trial

BACKGROUND

Superficial surgical site infections are a common post-operative complication. They also place a considerable financial burden on healthcare. The use of prophylactic negative pressure wound therapy has been advocated to reduce wound infection rates. However, there is debate around its routine use. The purpose of this trial is to determine if prophylactic negative pressure wound therapy reduces post-operative wound complications in patients undergoing laparotomy.

METHODS/DESIGN

This multi-centre randomised controlled trial will compare standard surgical dressings (control) to two competing negative pressure wound therapy dressings (Prevena™ and PICO™). All patients will be over 18 years, who are undergoing an emergency or elective laparotomy. It is intended to enrol a total of 271 patients for the trial.

DISCUSSION

The PROPEL trial is a multi-centre randomised controlled trial of patients undergoing laparotomy. The comparison of standard treatment to two commercially available NPWT will help provide consensus on the routine management of laparotomy wounds.

TRIAL REGISTRATION

This study is registered with ClinicalTrials.gov (NCT number NCT03871023).

An evaluation of the quality and content of web-based stoma information

AIM

Although the internet is commonly the first port of call for medical information, it provides unregulated data of variable quality. We aimed to evaluate commonly accessed web-based information on intestinal stomas using validated and novel scoring systems.

METHOD

The keywords 'stoma', 'colostomy', 'ileostomy' and 'bowel bag' were entered into the most commonly used internet search engines (Google, Bing and Yahoo). The first ten websites from each search were analysed using the validated Journal of the American Medical Association (JAMA) benchmark criteria and DISCERN scoring systems. A novel stoma-specific score was devised and applied.

RESULTS

Forty-three unique websites were identified. The majority (49%) were from nonprofit or governmental agencies and 9% were from commercial entities. The mean total DISCERN score for all websites was 42.4 ± 10.2 (maximum possible score = 75). The mean JAMA and stoma-specific scores were 2.1 ± 1.0 (maximum possible score = 4) and 12.9 ± 6.1 (maximum possible score = 27). The lowest JAMA scores were in the category of attribution, with 70% of websites lacking references for the information provided. A total of 88% displayed disclosure/paid advertiser information. Surgery was described in 67%. An image or diagram was provided in 58% and in 72% a stoma therapist/nurse was mentioned. Information on when to seek medical help was provided in 51%.

CONCLUSION

Web-based information on stomas is of variable content and quality. Authorship and information sources are often unclear. Only half provided information on when to seek medical help for complications including high output and dehydration. These findings should be highlighted to patients who utilize the internet to obtain information on stomas.

A giant duodenal diverticulum causing Lemmel syndrome

An 80-year-old female, with a known periampullary giant duodenal diverticulum, presented to the emergency department with general deterioration. While not clinically icteric, her laboratory investigations revealed an obstructive jaundice. MRCP demonstrated mild distension of the gallbladder with several calculi. There was intra- and extra-hepatic biliary dilatation to the level of the ampulla. A giant fluid and air filled periampullary duodenal diverticulum measuring ~8 cm in the long axis was noted. The CBD was dilated to the level of this diverticulum and the cause of the patient’s biliary dilatation and obstruction. A rare pancreaticobiliary complication of duodenal diverticula is Lemmel syndrome. Lemmel syndrome is defined as an obstructive jaundice caused by a periampullary duodenal diverticulum compressing the intra-pancreatic portion of the common bile duct with resultant dilatation of the extra- and intra-hepatic bile ducts. Recognition of this condition is important, as delayed diagnosis can result in unnecessary further investigations.

Rectal cancer in the elderly: A review of treatment variances between younger and older patients

839

Background: Rectal cancer (RC) treatment involves multiple modalities with tolerability a concern for some older patients (pts). However, fit older pts have outcomes similar to those of younger pts. We examined the treatment of RC in older pts compared to younger counterparts. Methods: Pts diagnosed with early stage and locally advanced RC from January 2014 to January 2016 were identified from a prospectively maintained electronic database. Characteristics were ascertained through retrospective analysis of pt records. Associations between categorical variables was tested using chi- square. Results: 116 pts diagnosed with RC were identified. Median age was 67 (range 36- 95). 47 (41%) were ≥ 70 years old. Stage distribution is summarised in the Table. Eight pts with stage I disease had rectal polyp cancers, fully resected at endoscopy. 108 were discussed at multidisciplinary meeting (MDM). Treatment (tx) recommendations based on clinical stage and ultimate tx received are outlined in the Table. Clinical Stage and MDM Outcomes Older pts were less likely to receive recommended NACRT than those < 70 (52% and 85% respectively). All pts ≥ 70 who received NACRT completed a full course successfully. Older pts were less likely to proceed to curative resection than younger pts (76% and 94% respectively). Average length of hospital stay was longer in pts ≥ 70: 22.9 vs. 16.6 days in pts < 70. Hospital readmission within 30 days in ≥ 70 vs. < 70 was 9% and 3% respectively. There was no statistical difference in the likelihood of receiving AC based on age. 25% of older pts required dose reductions of AC; 38% did not complete the planned number of cycles. Conclusions: While most older pts tolerated NACRT without significant toxicity, post- operative recovery and tolerability of AC varies widely. Comprehensive geriatric assessment may be useful in guiding tx decisions, and ensuring best outcomes, in this heterogeneous group.[Table: see text]

Population-based cohort study of variation in the use of emergency cholecystectomy for benign gallbladder diseases

Background

The aims of this prospective population-based cohort study were to identify the patient and hospital characteristics associated with emergency cholecystectomy, and the influences of these in determining variations between hospitals.

Methods

Data were collected for consecutive patients undergoing cholecystectomy in acute UK and Irish hospitals between 1 March and 1 May 2014. Potential explanatory variables influencing the performance of emergency cholecystectomy were analysed by means of multilevel, multivariable logistic regression modelling using a two-level hierarchical structure with patients (level 1) nested within hospitals (level 2).

Results

Data were collected on 4744 cholecystectomies from 165 hospitals. Increasing age, lower ASA fitness grade, biliary colic, the need for further imaging (magnetic retrograde cholangiopancreatography), endoscopic interventions (endoscopic retrograde cholangiopancreatography) and admission to a non-biliary centre significantly reduced the likelihood of an emergency cholecystectomy being performed. The multilevel model was used to calculate the probability of receiving an emergency cholecystectomy for a woman aged 40 years or over with an ASA grade of I or II and a BMI of at least 25·0 kg/m2, who presented with acute cholecystitis with an ultrasound scan showing a thick-walled gallbladder and a normal common bile duct. The mean predicted probability of receiving an emergency cholecystectomy was 0·52 (95 per cent c.i. 0·45 to 0·57). The predicted probabilities ranged from 0·02 to 0·95 across the 165 hospitals, demonstrating significant variation between hospitals.

Conclusion

Patients with similar characteristics presenting to different hospitals with acute gallbladder pathology do not receive comparable care.

Short-term outcomes following the use of self-expanding metallic stents in acute malignant colonic obstruction--a single centre experience

BACKGROUND

Colonic self-expanding metallic stents (SEMS) may provide prompt relief of acute malignant colorectal obstruction (AMCO) and are increasingly used either palliatively or as a bridge to surgery (BTS) in patients in whom a definitive surgical approach is unsuitable. We evaluated short-term outcomes of malignant colorectal obstructive patients who underwent SEMS insertion in our institution over a 3-year period.

METHODS

A prospectively maintained database was reviewed to identify all patients who presented to our institution with AMCO between August 2010 and 2013 and who were treated with a SEMS either temporarily or permanently. Additional data was retrieved from chart reviews and operation notes.

RESULTS

Sixteen patients (12 males, 4 females) each had a single stent inserted during the study period, either palliatively (n = 11) or as a BTS (n = 5). The technical and clinical success rates were both 87.5% (14/16). The two unsuccessful stenting cases both had disseminated disease and required emergency surgery while five patients with curable disease proceeded to elective resections. There was no procedure-related mortality or stent-related perforations. The mean (standard deviation) length of stay post acute surgery was longer than elective surgery [45 ± 21.2 vs. 15.8 ± 4.0, days]. All patients in the BTS group were stoma-free post-operatively, while both patients who had emergency surgery ended up with permanent stomas. Finally, the stent complication rate was 6.2% (1/16), secondary to migration.

CONCLUSIONS

Although limited by a small sample size, the study shows that SEMS have favourable short-term outcomes. Further adequately powered trials are needed to confirm those findings.

Internal hernia following total gastrectomy with Roux-en-Y reconstruction

Internal herniation is a well-described complication after a gastric bypass, particularly when performed laparoscopically, although it is rarely described following a total gastrectomy. A 55-year-old lady presented with a 24-hour history of vomiting and rigors 10 months after a radical total gastrectomy with Roux-en-Y reconstruction for a gastric adenocarcinoma. Computed tomography (CT) showed a complete small bowel obstruction and a mesenteric swirl sign, indicating a possible internal hernia. The entire small bowel was found at laparotomy to have migrated through the mesenteric defect adjacent to the site of the previous jejunojejunostomy and was dark purple and aperistaltic. The small bowel was reduced through the defect. At a second laparotomy, the small bowel looked healthy and the defect was repaired. Postoperative recovery was unremarkable. Of numerous signs described, the mesenteric swirl sign is considered the best indicator on CT of an internal hernia following Roux-en-Y reconstruction in gastric bypass surgery. A swirl sign on CT in a patient with abdominal pain should always raise the suspicion of an internal hernia.

An unusual presentation of Boerhaave Syndrome: a case report

We present a unique case of Boerhaave Syndrome that may highlight the spectrum of barotrauma from a Mallory-Weiss tear to full-thickness perforation. In this case, perforation only became evident following air insufflation at endoscopy.

Growth arrest-specific gene 6 expression in human breast cancer

Growth arrest-specific gene 6 (Gas6), identified in 1995, acts as the ligand to the Axl/Tyro3 family of tyrosine kinase receptors and exerts mitogenic activity when bound to these receptors. Overexpression of the Axl/Tyro3 receptor family has been found in breast, ovarian and lung tumours. Gas6 is upregulated 23-fold by progesterone acting through the progesterone receptor B (PRB). Recently, Gas6 has been shown to be a target for overexpression and amplification in breast cancer. Quantitative real-time PCR analysis was used to determine the levels of Gas6 mRNA expression in 49 primary breast carcinomas. Expression of PRB protein was evaluated immunohistochemically with a commercially available PRB antibody. The results showed a positive association between PRB protein and Gas6 mRNA levels (P=0.04). Gas6 correlated positively with a number of favourable prognostic variables including lymph node negativity (P=0.0002), younger age at diagnosis (P=0.04), smaller size of tumours (P=0.02), low Nottingham prognostic index scores (P=0.03) and low nuclear morphology (P=0.03). This study verifies for the first time the association between PRB and Gas6 in breast cancer tissue.

Progesterone receptor B (PRB) promoter hypermethylation in sporadic breast cancer: progesterone receptor B hypermethylation in breast cancer

INTRODUCTION

Oestrogen receptor alpha (ER alpha) is traditionally measured on all breast tumour specimens to identify those patients more likely to respond to anti-oestrogens. Progesterone receptor (PR) status has contributed useful information in defining more responsive subgroups. PR negativity may be a marker for increased signalling through growth factor receptor tyrosine kinase pathways. Progesterone acts through two PRs, PRA and PRB. PRB, the functionally active PR, can be silenced by promoter hypermethylation.

METHODS

Following DNA and RNA extraction from 94 breast carcinomas, the methylation status of the PRB promoter was assessed by sodium bisulphite modification and methylation sensitive PCR (MSP). A quantitative realtime PCR analysis (QRTPCR) was used to determine the levels of PRB mRNA expression. Protein expression was evaluated immunohistochemically with a commercially available PRB antibody.

RESULTS

76% of the primary breast carcinoma samples demonstrated a methylated band for PRB. PRB methylation significantly compromised total PR immunohistochemistry (IHC) expression (P = 0.03). PRB mRNA correlated positively with total PR IHC (r = 0.58, P = 0.04), ER alpha IHC (P = 0.02), and tumour grade (P = 0.01). PRB protein expression was significantly associated with a number of favourable prognostic variables including smaller (P = 0.004) lower grade (P = 0.007), ER alpha IHC positive tumours (P < 0.001), and tumours with a low Nottingham Prognostic Index (NPI) (P = 0.0008). PRB mRNA levels were significantly associated with better overall survival (P = 0.04) in a univariate analysis.

CONCLUSION

The majority of tumours were methylated for PRB. This did not directly compromise PRB expression suggesting that other factors may down regulate the PR gene. When PRB was expressed, it correlated with good prognostic markers and better overall survival.

A framework for the evaluation of chemical structure databases

Access to desk-top structure and reaction databases through applications such as Chemical Abstracts' SciFinder, MDL's Beilstein CrossFire, and ISIS Reaction Browser has led to changes in information seeking habits of research chemists, the impact of which has implications when database purchasing decisions are made. A semiquantitative assessment is proposed which takes into account key aspects of structure and reaction databases. Assessment criteria are identified which can be weighted according to an organization's information needs. Values are then assigned to criteria for each data source, after which a formula is applied which leads to an indication of the relative value of systems under consideration. The formula takes into account the cost of database products and also the incremental benefit of adding a new system to an existing collection. This work is presented as a generic approach to the evaluation of databases and is not limited in scope to only structure and reactions databases.

Phenotypic and molecular analysis of six human cell lines derived from patients with plasma cell dyscrasia

Cell lines RPMI 8226, JJN3, U266 B1, NCI-H929 (all EBV-) and ARH77 and HS-Sultan (both EBV+) have been extensively characterized in this study. EBV- lines expressed the phenotype (CD138-, CD19+, CD20+) whereas EBV+ were (CD138+, CD19-, CD20-). CD56 expression was restricted to EBV- cell lines, with the exception of U266 B1, whereas PCA-1 was strongly expressed on five of the six cell lines. Only EBV+ cell lines bound peanut-agglutinin (PNA). However, all cell lines bound the lectin Jacalin that binds the same receptor as PNA, irrespective of the receptors sialylation status. By RT-PCR and direct sequencing of their IgH V/D/J domains, ARH77 was demonstrated to use the germline sequence VH4-34/dm1/JH6b, whereas no arrangement was demonstrated for RPMI 8226, suggesting IgH gene deletion or mutation. HLA class I and II antigens were detected using HLA typing on all cell lines warranting their use as suitable targets for HLA-restricted cytotoxic T cells. By sensitive RT-PCR, mRNA for IL-6, IL-6R and TNFbeta was found expressed in all cell lines. IL-1 mRNA expression was predominantly associated with the EBV+ phenotype. Although mRNA for IL-3 and GM-CSF was never detected, transcripts for c-kit ligand and, more commonly, its receptor were. Likewise GM-CSF, M-CSF and erythropoietin mRNA transcripts were detected in the majority of cell lines.

CD34+-selected peripheral blood progenitor cell transplantation in patients with multiple myeloma: tumour cell contamination and outcome

Thirty-six patients with multiple myeloma (23 PR1, nine PR2, four stable disease) were entered into a pilot study evaluating the use of CD34+-selected peripheral blood progenitor cell transplantation (PBPCT) following high-dose melphalan alone or high-dose melphalan and total body irradiation. Peripheral blood progenitor cells (PBPCs) were mobilized with cyclophosphamide and granulocyte colony stimulating factor (G-CSF). CD34+ selection using the Cellpro Ceprate-SC system was performed in 22 cases with an adequate yield in 20. 10 patients failed to mobilize sufficient cells to permit selection and in four cases selection was not performed for other reasons. 16 patients therefore received unselected PBPC. Tumour cell contamination was evaluated by IgH gene fingerprinting (fpPCR). Harvested PBPC were fpPCR positive in 13/20 CD34+-selected cases and remained positive after selection in seven. Harvested PBPC were studied in 9/16 patients receiving unselected cells; fpPCR was positive in five and negative in four. There was no difference in event-free survival (EFS) between the CD34+-selected group and the unselected group (median 21 and 26 months, respectively, P=ns). The CD34+-selection process therefore reduced contamination but did not eliminate it completely, and in this small non-randomized study there was no apparent clinical benefit of CD34+ selection.

A methodology for sampling and accessing homeless individuals in Melbourne, 1995-96

A methodology for sampling homeless populations in inner Melbourne was developed to study their health status and prevalence of tuberculosis. This paper describes the design, development and implementation of the project. The results of health status and tuberculosis analysis are published elsewhere. Involvement and interaction with local service providers and agencies to homeless people was central to the project throughout. A definitional construct of homelessness was developed, drawn from local and overseas literature and contemporary local experience. The study's aim was to obtain a representative sample of homeless individuals in various levels of accommodation and a convenience sample of those who were unaccommodated (streets and parks). A comprehensive sampling frame of accommodation options was constructed from available databases, and systematic sampling applied to produce a sample of 396 beds, from which 284 participants were enrolled. Convenience sampling of unaccommodated homeless individuals produced 100 participants. All agreed to undergo a comprehensive questionnaire, blood and Mantoux testing, the latter being completed successfully in 94%. Commonsense, cultural sensitivity and a non-threatening approach were critical to the success of the project and the security of the field workers. The methods described attempt to address recognised difficulties of sampling from homeless populations and should be reproducible both in the future and elsewhere. Potential for selection bias remains the main threat to validity, which the described methodology combined with adequate resources should help to address.

Moult speed predicts pairing success in male harlequin ducks

The bright plumage of male ducks in sexually dichromatic species is thought to have evolved through intense sexual selection. This study examined the relationship between the timing and speed of moult into this bright plumage and subsequent mating success of male harlequin ducks, Histrionicus histrionicus. Males that moulted relatively slowly had a lower chance of establishing a pair bond than others. The timing of moult was unrelated to whether a male obtained a mate. Moult speed and timing were not correlated within individual males, but were significantly repeatable in individual males over 2 years. Moult speed probably reflects the condition of males, whereas timing of moult is more likely to be related to the distance to an individual's breeding area, which determines the timing of arrival to the moulting grounds. In waterfowl species that have been studied, males usually form dominance hierarchies before pairing and females tend to choose dominant males. We suggest that male harlequin ducks that moult slowly are poor-quality individuals, which are relegated to subordinate status and are unlikely to attract a mate the following autumn. Copyright 1998 The Association for the Study of Animal Behaviour. Copyright 1998 The Association for the Study of Animal Behaviour.

The G beta gamma sensitivity of a PI3K is dependent upon a tightly associated adaptor, p101

Two highly similar, PtdIns(4,5)P2-selective, G beta gamma-activated PI3Ks were purified from pig neutrophil cytosol. Both were heterodimers, were composed of a 101 kDa protein and either a 120 kDa or a 117 kDa catalytic subunit, and were activated greater than 100-fold by G beta gammas. Peptide sequence-based oligonucleotide probes were used to clone cDNAs for the p120 and p101 species. The cDNA of p120 is highly related to p110 gamma, while the cDNA of p101 is not substantially related to anything in current databases. The proteins were expressed in and purified from insect and mammalian cells. They bound tightly to one another, both in vivo and in vitro, and in so doing, p101 amplified the effect of G beta gammas on the PI3K activity of p120 from less than 2-fold to greater than 100-fold.

Medical students in general practice: how do patients feel?

BACKGROUND

The General Medical Council has recommended that medical students should gain more experience in general practice.

AIM

The study set out to determine patients' reactions to the presence of medical students in general practice consultations.

METHOD

Patients attending a random sample of general practice surgeries completed a questionnaire following consultation with and without a medical student present in six general practices in the Oxford area.

RESULTS

The questionnaires were completed by 278 patients. Only eight (3%) of all respondents had negative responses to the presence of a medical student. Of those completing questionnaires following a teaching consultation, 107 (56%) felt positively about the presence of students, compared with 36 (41%) who had attended a nonteaching surgery. Only three patients (1%) felt the quality of the consultation to be impaired by the presence of a student, while 48 patients (17%) felt there to be some improvement. The majority felt that the sex of the student was unimportant, but significantly more female than male patients (17% versus 5%) felt that it made a difference.

CONCLUSION

Only a small proportion of patients object to the presence of a medical student in general practice consultations. A significant minority said that the presence of a student improves the consultation.

A heterotrimeric GTPase-regulated isoform of PI3K and the regulation of its potential effectors

We have purified two forms of phosphoinositide 3-kinase (PI3K) that are activated by heterotrimeric G-protein beta gamma-subunits. These novel isoforms of PI3K are structurally distinct to those forms of PI3K which have already been cloned. They are both heterodimers made up of a p120 and a p101 and a p117 and a p101 protein. The p101 species in both heterodimers are identical and show no substantial homology with any other proteins or DNA sequences. The p117 and p120 are highly related. The p101 and p120 species have been cloned from a pig neutrophil mRNA library. The p120 has similarities with other known PI3K catalytic subunits. They may be responsible for conferring cells with the capacity to produce phosphatidylinositol (3,4,5)-trisphosphate in response to activation of G-protein-coupled receptors. Activation of both the monomeric G-protein rac and PI3K(s) have been implicated in receptor-stimulated membrane-ruffling. We have observed that agonist-stimulated guanine nucleotide exchange on rac can be inhibited by a variety of PI3K inhibitors. This suggests PI3K may lie upstream of rac in receptor-driven pathways regulating cell movement.

Activation of phosphoinositide 3-kinase is required for PDGF-stimulated membrane ruffling

BACKGROUND

There is substantial evidence that phosphoinositide 3-kinase (PI 3-kinase) is a critical component of signalling pathways used by the cell-surface receptors for a variety of mammalian growth factors and other hormones. The physiological product of this enzyme is a highly polar membrane lipid called phosphatidylinositol (3,4,5)-trisphosphate This lipid has been postulated to act as a second-messenger in cells but its putative targets are still unknown.

RESULTS

A particular rearrangement of actin filaments, which results in membrane ruffling, is elicited by the activation of PDGF beta-receptors expressed in cultured porcine aortic endothelial cells. We have found that this consequence of PDGF beta-receptor activation is inhibited by three independent manipulations of PI 3-kinase activity: firstly, by the deletion of tyrosine residues in the PDGF beta-receptor to which PI 3-kinase binds; secondly, by the overexpression of a mutant 85 kD PI 3-kinase regulatory subunit to which the catalytic kinase subunit cannot bind; and thirdly, by the addition of the fungal metabolite wortmannin, which is a potent inhibitor of the catalytic activity of PI 3-kinase.

CONCLUSIONS

These results argue strongly that phosphatidylinositol (3,4,5)-trisphosphate synthesis is required for growth-factor-stimulated membrane ruffling in porcine aortic endothelial cells, and suggest that synthesis of this lipid may be part of a signalling pathway leading to direct or indirect activation of the small GTP-binding protein Rac.

Plastics processing: statistics, current practices, and evaluation

The health care industry uses a huge quantity of plastic materials each year. Much of the machinery currently used, or supplied, for plastics processing is unsuitable for use in a clean environment. In this article, the author outlines the reasons for the current situation and urges companies to re-examine their plastic-processing methods, whether performed in-house or subcontracted out. Some of the factors that should be considered when evaluating plastics-processing equipment are outlined to assist companies in remaining competitive and complying with impending EC regulations on clean room standards for manufacturing areas.