Association of day-case rates with post COVID-19 recovery of elective laparoscopic cholecystectomy activity across England.

INTRODUCTION: The aim of this study was to investigate the safety of day-case laparoscopic cholecystectomy, and the association between day-case rates and, post the COVID-19 pandemic, recovery of activity to prepandemic levels for integrated care boards (ICBs) in England. METHODS: This was a retrospective observational study of the Hospital Episodes Statistics (HES) data set. Elective laparoscopic cholecystectomies for the period 1 January 2019 to 31 December 2022 were identified. Activity levels for 2022 were compared with those for the whole of 2019 (baseline). Day-case activity was identified where the length of stay recorded in the HES was zero days. RESULTS: Data were available for 184,252 patients across the 42 ICBs in England, of which 120,408 (65.3%) were day-case procedures. By December 2022, activity levels for the whole of England had returned to 88.2% of prepandemic levels. The South West region stood out as having recovered activity levels to the greatest extent, with activity at 97.3% of prepandemic levels during 2022. The South West also had the highest postpandemic day-case rate at 74.9% of all patients seen as a day-case during 2022; this compares with an England average of 65.3%. At an ICB level, there was a significant correlation between day-case rates and postpandemic activity levels (r = 0.362, p = 0.019). There was no strong or consistent evidence that day-case surgery had poorer patient outcomes than inpatient surgery. CONCLUSIONS: Recovery of elective laparoscopic cholecystectomy activity has been better in South West England than in other regions. Increasing day-case rates may be important if ICBs in other regions are to increase activity levels up to and beyond prepandemic levels.

Factors associated with conversion from day-case to in-patient elective inguinal hernia repair surgery across England: an observational study using administrative data.

PURPOSE: Elective primary inguinal hernia repair surgery is increasingly being conducted as a day-case procedure. However, some patients planned for day-case surgery have to stay in hospital for at least one night. The aim of this study was to identify the factors associated with conversion from day-case to in-patient management for elective inguinal hernia repair surgery. METHODS: This was an exploratory retrospective analysis of observational data from the Hospital Episode Statistics dataset for England. All patients aged ≥ 17 years undergoing a first elective inguinal hernia repair between 1st April 2014 and 31st March 2022 that was planned as day-case surgery were identified. The exposure of interest was discharged on the day of admission (day-case) or requiring overnight stay. The primary outcome of interest was 30-day emergency readmission with an overnight stay. For reporting, providers were aggregated to an Integrated Care Board (ICB) level. RESULTS: A total of 351,528 planned day-case elective primary inguinal hernia repairs were identified over the eight-year study period. Of these, 45,305 (12.9%) stayed in hospital for at least one night and were classed as day-case to in-patient stay conversions. Patients who converted to in-patient stay were older, had more comorbidities, and were more likely to have bilateral surgery and be operated on by a low-annual volume surgeon. Post-procedural complications were strongly associated with conversion. Across the 42 ICBs in England, model-adjusted conversion rates varied from 3.3% to 21.3%. CONCLUSIONS: There was considerable variation in conversion to in-patient stay rates for inguinal hernia repair across ICBs in England. Our findings should help surgical teams to better identify patients suitable for day-case inguinal hernia repair and plan discharge services more effectively. This should help to reduce the variation in conversion rates.

Day-case and in-patient elective inguinal hernia repair surgery across England: an observational study of variation and outcomes.

PURPOSE: Elective primary inguinal hernia repair surgery is increasingly being conducted as a day-case procedure. However, in England there is evidence of wide variation in day-case rates across hospitals. Reducing the extent of this variation has the potential to support more efficient use of resources (e.g., clinician time, hospital beds) and help the recovery of elective surgical activity following the COVID-19 pandemic. The aims of this study were to explore the extent of variation in day-case rates across healthcare providers in England and to evaluate the safety of day-case elective primary inguinal hernia repair surgery. METHODS: This was an exploratory, retrospective analysis of observational data from the Hospital Episode Statistics data set for England. All patients aged ≥ 17 years undergoing a first elective inguinal hernia repair between 1st April 2014 and 31st March 2022 were identified. The exposure of interest was day-case or in-patient stay, and the primary outcome of interest was 30-day emergency readmission with an overnight stay. For reporting, providers were aggregated to an Integrated Care Board (ICB) level. RESULTS: A total of 413,059 elective primary inguinal hernia repairs were identified over the 8-year study period. Of these, 326,833 (79.1%) were day-case procedures. During the most recent financial year (2021-22), the highest day-case rate for an ICB was 93.8% and the lowest 66.1%. After adjusting for covariates, day-case surgery was associated with significantly lower rates of 30-day emergency readmission (odds ratio (OR) 0.61, 95% confidence interval (CI) 0.58-0.64, p < 0.001) and for the secondary outcomes 180-day mortality and haemorrhage, infection and pain at 30-day post-discharge. Rates of 30-day emergency readmission were significantly lower in ICBs with high rates of day-case surgery (OR 0.84, 95% CI 0.74-0.96, p < 0.001) than in ICBs with low rates of day-case surgery, although rates of post-procedural haemorrhage within 30 days of discharge were significantly higher in trusts with high day-case rates (OR 1.20, 95% CI 1.04-1.40, p = 0.015). CONCLUSIONS: For the outcomes studied, we found no consistent evidence that day-case elective inguinal hernia repair was unsafe for selected patients. Currently, there is substantial variation between ICBs in terms of delivering day-case surgery. Reducing this variability may help address the current pressures on the NHS in elective surgery.

Comorbidities Associated with Worse Outcomes Among Inpatients Admitted for Acute Gastrointestinal Bleeding.

BACKGROUND: Multimorbidity increases healthcare resource utilization. Little is known on specific comorbidity combinations. AIMS: To identify comorbidities associated with increased resource utilization among inpatients admitted for gastrointestinal bleeding (GIB). METHODS: This retrospective cross-sectional study, 1/2010-5/2018 at the University Hospital Zurich, Switzerland, analyzed electronic health records of patients with upper (UGIB) and lower (LGIB) GIB, focusing on length of stay (LOS) and 30-day readmissions for resource use and clinical outcomes, investigated by multivariable regression adjusted for antithrombotics. RESULTS: Of 1101 patients, 791 had UGIB and 310 LGIB, most often melena and bleeding diverticula, respectively. In UGIB, thromboembolic events showed a trend toward 27% increased LOS (1.27; 95% confidence interval [CI] 1.00-1.61), antithrombotics independently associated with 46% increased LOS (1.46; 95% CI 1.32-1.62). Cancer (odds ratio [OR] 2.86; 95% CI 1.68-4.88) independently associated with 30-day readmissions, anemia showed a trend (OR 1.68; 95% CI 1.00-2.84). In LGIB, none of the investigated comorbidities associated with increased LOS, but antithrombotics independently associated with 25% increased LOS (1.25; 95% CI 1.07-1.46). Atrial fibrillation/flutter (OR 2.69; 95% CI 1.06-6.82) and cancer (OR 4.76; 95% CI 1.40-16.20) associated strongly with 30-day readmissions. CONCLUSIONS: In both groups, cancer associated with 30-day readmissions, antithrombotics with increased LOS. Thromboembolic events and anemia showed clinically important trends in UGIB. Atrial fibrillation/flutter associated with 30-day readmissions in LGIB. Prospective studies are needed to investigate these complex multimorbid populations and establish appropriate guidelines.

Sex differences in the splenic flexure.

INTRODUCTION Anecdotally, surgeons claim splenic flexure mobilisation is more difficult in male patients. There have been no scientific studies to confirm or disprove this hypothesis. The implications in colorectal surgery could be profound. The aim of this study was to assess quantitatively whether there is an anatomical difference in the position of the splenic flexure between men and women using computed tomography (CT). METHODS Portal venous phase CT performed for preoperative assessment of colorectal malignancy was analysed using the hospital picture archiving and communication system. The splenic flexure was compared between men and women using two variables: anatomical height corresponding to the adjacent vertebral level (converted to ordinal values between 1 and 17) and distance from the midline. RESULTS In total, 100 CT images were analysed. Sex distribution was even. The mean ages of the male and female patients were 68.1 years and 66.7 years respectively (p=0.630). The mean vertebral level for men was 8.88, equating to the inferior half of the T11 vertebral body (range: 1-17 [superior half of T9 to inferior half of L2]), and 11.36 for women, equating to the inferior half of the T12 vertebral body (range: 4-16 [superior half of T10 to superior half of L2]). This difference was statistically significant (p=0.0001) and is equivalent to one whole vertebra. The mean distance from the midline was 160.8mm (range: 124-203mm) for men and 138.2mm (range: 107-185mm) for women (p<0.0001). CONCLUSIONS The splenic flexure is both higher and further from the midline in men than in women. This provides one theory as to why mobilising the splenic flexure may be more difficult in male patients.

Anatomical siting of the splenic flexure using computed tomography.

INTRODUCTION Often, left-sided colorectal surgery requires splenic flexure mobilisation (SFM) to allow a tension-free anastomosis to be carried out. This step is difficult and not without risk. We investigated a system of anatomical siting of the splenic flexure using computed tomography (CT). METHODS The Shrewsbury Splenic Flexure Siting (SSFS) system involves siting of the splenic flexure using the vertebral level (VL) as a reference point. We asked three surgical registrars (SRs) to analyse 20 CT scans of patients undergoing colonic resection to ascertain the anatomical site of the splenic flexure using the SSFS system. The distance from the centre of the vertebral body to the lateral edge (CVBL) of the splenic flexure was measured, as was the distance from the centre of the vertebral body to the inner abdominal wall (CVBI) along the same line, on axial images. RESULTS VL assessment demonstrated substantial inter-observer agreement with a kappa (κ) value of 0.742 (95% confidence interval (CI), 0.463-0.890). CVBL and CVBI demonstrated very strong inter-observer agreement (CVBL: κ = 0.905 (95% CI, 0.785-0.961); CVBI: 0.951 (0.890-0.979) (p<0.001). Overall, there was strong correlation between assessments by all three SRs across the three variables measured. CONCLUSIONS The SSFS system is an accurate method to site the splenic flexure anatomically using CT. We can use the SSFS system to develop a validated scoring system to help colorectal surgeons assess the difficulty of SFM.

Hsp40 molecules that target to the ubiquitin-proteasome system decrease inclusion formation in models of polyglutamine disease.

We studied the ability of heat shock, DnaJ-like-1 (HSJ1) proteins (which contain DnaJ and ubiquitin-interacting motifs) to reduce polyglutamine-mediated inclusion formation. The experiments demonstrated that expression of heat shock protein 70 (hsp70), hsp40, HSJ1a, and HSJ1b significantly reduced protein inclusion formation in a model of spinal and bulbar muscular atrophy (SBMA). HSJ1a also mediated a significant decrease in the number of inclusions formed in a primary neuronal model of protein aggregation. Studies to elucidate the mechanisms underlying these reductions showed that hsp70 and hsp40 increased chaperone-mediated refolding. In contrast, expression of HSJ1 proteins did not promote chaperone activity but caused an increase in ubiquitylation. Furthermore, HSJ1a was associated with a ubiquitylated luciferase complex, and in the presence of HSJ1a but not an HSJ1a UIM mutant (HSJ1a-deltaUIM) there was a reduction in luciferase protein levels. Together these results show that HSJ1 proteins mediated an increase in target protein degradation via the ubiquitin-proteasome system (UPS). We also found that the expression of HSJ1a significantly decreased the number of neurons containing inclusions in an in vivo model of polyglutamine disease. These findings indicate that targeted modification of the UPS to facilitate degradation of misfolded proteins may represent a highly effective therapeutic avenue for the treatment of polyglutamine disease.

Cytosolic and ER J-domains of mammalian and parasitic origin can functionally interact with DnaK.

Both prokaryotic and eukaryotic cells contain multiple heat shock protein 40 (Hsp40) and heat shock protein 70 (Hsp70) proteins, which cooperate as molecular chaperones to ensure fidelity at all stages of protein biogenesis. The Hsp40 signature domain, the J-domain, is required for binding of an Hsp40 to a partner Hsp70, and may also play a role in the specificity of the association. Through the creation of chimeric Hsp40 proteins by the replacement of the J-domain of a prokaryotic Hsp40 (DnaJ), we have tested the functional equivalence of J-domains from a number of divergent Hsp40s of mammalian and parasitic origin (malarial Pfj1 and Pfj4, trypanosomal Tcj3, human ERj3, ERj5, and Hsj1, and murine ERj1). An in vivo functional assay was used to test the functionality of the chimeric proteins on the basis of their ability to reverse the thermosensitivity of a dnaJ cbpA mutant Escherichia coli strain (OD259). The Hsp40 chimeras containing J-domains originating from soluble (cytosolic or endoplasmic reticulum (ER)-lumenal) Hsp40s were able to reverse the thermosensitivity of E. coli OD259. In all cases, modified derivatives of these chimeric proteins containing an His to Gln substitution in the HPD motif of the J-domain were unable to reverse the thermosensitivity of E. coli OD259. This suggested that these J-domains exerted their in vivo functionality through a specific interaction with E. coli Hsp70, DnaK. Interestingly, a Hsp40 chimera containing the J-domain of ERj1, an integral membrane-bound ER Hsp40, was unable to reverse the thermosensitivity of E. coli OD259, suggesting that this J-domain was unable to functionally interact with DnaK. Substitutions of conserved amino acid residues and motifs were made in all four helices (I-IV) and the loop regions of the J-domains, and the modified chimeric Hsp40s were tested for functionality using the in vivo assay. Substitution of a highly conserved basic residue in helix II of the J-domain was found to disrupt in vivo functionality for all the J-domains tested. We propose that helix II and the HPD motif of the J-domain represent the fundamental elements of a binding surface required for the interaction of Hsp40s with Hsp70s, and that this surface has been conserved in mammalian, parasitic and bacterial systems.

Drug treatment for faecal incontinence in adults.

BACKGROUND: Faecal incontinence is a common symptom which causes significant distress and reduction in quality of life. Available treatment options for faecal incontinence include conservative treatments (biofeedback, pelvic floor muscle training, dietary manipulation or drug therapy) or surgical treatments (e.g. sphincter repair, post anal repair, neosphincter). Drug treatment is often given either alone or in combination with other treatment modalities. OBJECTIVES: To assess the effects of drug therapy for the treatment of faecal incontinence. In particular, to assess the effects of individual drugs relative to placebo or other drugs, and to compare drug therapy with other treatment modalities. SEARCH STRATEGY: We searched the Cochrane Incontinence Group trials register (January 2003) and the reference lists of relevant articles. Date of the most recent search: January 2003. SELECTION CRITERIA: All randomised or quasi-randomised controlled trials of the use of pharmacological agents for the treatment of faecal incontinence in adults. DATA COLLECTION AND ANALYSIS: Working independently, reviewers selected studies from the literature, assessed the methodological quality of each trial, and extracted data. MAIN RESULTS: Eleven trials were identified for inclusion in this review. Nine trials were of cross-over design. Seven trials included only people with faecal incontinence related to liquid stool (either chronic diarrhoea or following ileoanal pouch surgery). Three trials (total 58 participants) compared topical phenylephrine gel with placebo. Two trials (56 participants) compared loperamide with placebo. One trial (11 participants) compared loperamide oxide with placebo. One trial (15 participants) compared diphenoxylate plus atropine with placebo. One trial (17 participants) compared sodium valproate with placebo. One trial (30 participants) compared loperamide with codeine with diphenoxylate plus atropine. Two further trials (total 265 participants) assessed the use of lactulose in elderly people.No studies comparing drugs with other treatment modalities were identified. There was limited evidence that antidiarrhoeal drugs and drugs which enhance anal sphincter tone may reduce faecal incontinence in patients with liquid stools. However, the trials were small and of short duration. REVIEWER'S CONCLUSIONS: The small number of trials identified for this review assessed several different drugs in a variety of patient populations. The focus of most of the included trials was on the treatment of diarrhoea, rather than faecal incontinence. There is little evidence to guide clinicians in the selection of drug therapies for faecal incontinence. Larger, well-designed controlled trials, which include clinically important outcome measures, are required.

A randomized, controlled trial of diathermy hemorrhoidectomy vs. stapled hemorrhoidectomy in an intended day-care setting with longer-term follow-up.

PURPOSE: Hemorrhoidectomy is the most effective long-term treatment for hemorrhoids. Although it is possible to perform hemorrhoidectomy as a day case with a high degree of patient satisfaction, patients take an average of 14 days off work after surgery. Stapled hemorrhoidectomy is believed to be less painful than conventional hemorrhoidectomy and should allow an earlier return to work. The aim of this study was to compare both the immediate and the long-term results of stapled hemorrhoidectomy with diathermy hemorrhoidectomy in patients with prolapsing internal hemorrhoids in an intended day-care setting. METHODS: Thirty-one patients were randomly assigned to undergo diathermy hemorrhoidectomy (n = 16) or stapled hemorrhoidectomy performed with a purpose-designed endoluminal stapling device, PPH01T (n = 15). All operations were planned as day or short-stay cases. All patients received lactulose, commenced preoperatively, together with postoperative topical glyceryl trinitrate and oral metronidazole. Patients were assessed by structured interview to assess their symptoms before and after surgery, with an intended follow-up of six months. All patients completed a 10-cm visual analog pain scale daily for the first ten days after surgery. RESULTS: The total pain score (sum of all pain scores) was significantly higher in the diathermy group (50 (range, 9.8-79.9) vs. 19.6 (range, 1.3-89.5), P = 0.03). Patients took a median of 14 (range, 3-21) days off work after diathermy hemorrhoidectomy compared with 10 (range, 3-38) days for the patients undergoing stapled hemorrhoidectomy (P = 0.15). At long-term follow-up, three patients (all in the stapled group) developed new symptoms of fecal urgency and anal pain, and three patients required further surgery to remove symptomatic external hemorrhoids after stapled hemorrhoidectomy. CONCLUSIONS: Although stapled hemorrhoidectomy is less painful in the short term, this does not lead to a significantly earlier return to work, and some patients develop new symptoms at long-term follow-up.

In vitro studies show that Hsp70 can be released by glia and that exogenous Hsp70 can enhance neuronal stress tolerance.

Glial cells release a variety of molecules that support neuronal function. Because heat shock proteins (Hsps) are important in the survival of neurons subjected to metabolic stress, the possibility that glia can release the inducible form of the 70 kDa Hsp (Hsp70) was examined. Additionally, the ability of neuronal cells to show increased stress tolerance by taking up a mixture of constitutive and inducible forms of Hsp70 (Hsc/Hsp70) added to the extracellular fluid was tested. Human T98G glioma cells and differentiated LA-N-5 neuroblastoma cells were used as model glia and neurons to investigate these points. Hsp70 was analyzed using affinity chromatography, Western blotting, and immunofluorescence microscopy. The glioma cells were shown to export Hsp70 into the culture medium whether under normal conditions or subjected to heat shock. The amount of glial Hsp70 released ranged from 5 to 15 pg per 10(6) cells per day, being greater following heat shock. Neuroblastoma cells took up biotinylated Hsc/Hsp70 within 1 h after it was added to the culture medium and it made them more resistant to heat shock (44 degrees C) and to staurosporine-induced apoptosis. This increased stress tolerance was especially important in neuroblastoma cells induced to differentiate with phorbol ester because those 'mature neurons' showed a 10-fold decline in endogenous Hsp70, which was accompanied by increased susceptibility to heat shock and staurosporine-induced apoptosis. These results suggest that extracellular Hsp70 may provide a means by which glia can affect neuronal function, perhaps enhancing neuronal stress tolerance.

Identification and characterization of a human mitochondrial homologue of the bacterial co-chaperone GrpE.

We have identified a novel human cDNA with a predicted protein sequence that has 28% amino acid identity with the E. coli Hsp70 co-chaperone GrpE and designated it HMGE. Even with this low level of amino acid identity the human sequence could be efficiently modelled on the X-ray structure of the E. coli protein, suggesting that there may be significant functional conservation. Indeed, HMGE expressed in E. coli as a GST fusion protein co-purified with the E. coli Hsp70 protein DnaK in the absence of ATP. DnaK could be released from the GST-HMGE with a Mg-ATP wash. Subcellular fractionation and immunocytochemistry studies using antisera raized against HMGE show that it is a mitochondrial protein. In contrast to studies of rat GrpE, however, HMGE also appears to bind the constitutive cytosolic Hsp70, Hsc70, in addition to mitochondrial Hsp70, Mt-Hsp70. We have previously shown that Hsc70 nucleotide-exchange is rate limiting in the presence of the DnaJ-protein, HSJ1b. However, HMGE was found to inhibit the HSJ1b-enhanced Hsc70 ATPase activity and may mediate this inhibition by binding the DnaJ-protein, HSJ1b. This is the first description of a direct interaction between a DnaJ protein and GrpE-like protein. These studies suggest that the structure of GrpE has been conserved throughout evolution and that the conserved structure can interact with several forms of Hsp70, but that HMGE cannot form part of the reaction cycle for cytosolic Hsc70.

Evidence-based practice in haemorrhoidectomy.

OBJECTIVE: Haemorrhoidectomy has proven long-term efficacy in the treatment of haemorrhoids, albeit at the price of increased pain and complications compared with other modalities. This study reviews the literature and describes best practice in the surgical treatment of haemorrhoids. METHODS: A Medline search was conducted using the keywords haemorrhoids or haemorrhoidectomy to identify clinical trials comparing different surgical treatments for haemorrhoids. RESULTS: Many studies were small and follow up was often short-term only. Surrogate measures such as post-operative pain scores and changes in anorectal physiology were commonly assessed in preference to efficacy in symptom reduction. Haemorrhoidectomy may be safely performed under general, local or regional anaesthesia according to patient fitness and local practice. Results of randomized controlled trials indicate that there open and closed techniques of haemorrhoidectomy are equivalent. There is no evidence to support the practice of laser haemorrhoidectomy. Diathermy haemorrhoidectomy achieves good haemostasis and permits an anal dressing to be omitted, but is not superior to conventional techniques. The use of preoperative lactulose and post-operative oral metronidazole is supported by randomized controlled trials. CONCLUSION: Haemorrhoidectomy is currently the most effective treatment for prolapsing haemorrhoids. There is little evidence to support the use of one surgical technique over another. With attention to detail and adjuncts to reduce post-operative pain, haemorrhoidectomy may be performed as day surgery.

Gender differences in the longitudinal pressure profile of the anal canal related to anatomical structure as demonstrated on three-dimensional anal endosonography.

BACKGROUND: Anal canal squeeze pressure is assumed to be due to external sphincter contraction, but the contribution of other muscles has not been explored. METHODS: Ten male and ten nulliparous female asymptomatic subjects had three-dimensional anal endosonography and manometry. Incremental squeeze pressures at 0. 5-cm intervals, expressed as a percentage of the maximum pressure recorded anywhere in the canal, were related to the following anatomical levels: puborectalis, overlap between external anal sphincter (EAS) and puborectalis, external and internal anal sphincters, and external anal sphincter only. Levels were determined by coronal and sagittal endosonographic reconstructions. RESULTS: Puborectalis was the same length in men and women (median 23.9 versus 27.1 mm) but represented a greater proportion of the anal canal in women (45 versus 61 per cent; P = 0.02). At the level of puborectalis alone, the pressure generated as a proportion of maximum anal canal pressure was 71 (range 32-100) per cent in men and 62 (range 32-100) per cent in women. At the level of the EAS alone, the pressure was 60 (4-98) per cent in men and 82 (41-100) per cent in women; where the external sphincter was overlapped by puborectalis, the pressure was 98 (60-100) per cent in men and 75 (47-100) per cent in women. CONCLUSION: Maximal anal canal squeeze pressure is found where the puborectalis overlaps the EAS. This segment represents a significant proportion of anal canal length in women.

Persistent pain and faecal urgency after stapled haemorrhoidectomy.

INTRODUCTION: Haemorrhoidectomy usually cures haemorrhoids. Day surgery is feasible, and is associated with high patients' satisfaction and few complications, but patients take an average of 2 weeks off work after surgery. Stapled haemorrhoidectomy has the potential to decrease postoperative pain and time off work. However, data on long-term efficacy and function are lacking. METHODS: 22 patients underwent stapled haemorrhoidectomy: seven in a pilot study, and 15 in a randomised controlled trial to compare the new stapled operation with diathermy haemorrhoidectomy in a day-case setting. All operations were done by one consultant surgeon. RESULTS: 16 patients were followed up for longer than 6 months, five of whom (31% [95% CI 8.5-54.0%]) developed symptoms of pain and faecal urgency which persisted for up to 15 months postoperatively. The randomised trial was suspended, and patients were investigated with endoanal ultrasonography, anorectal physiology, and examination under anaesthetic. All five affected patients were reviewed by two independent surgeons experienced in the stapled operation. In one patient, a fibroepithelial polyp was found adjacent to an anodermal ulcer; in the other patients, no abnormality was found. Four of the five affected patients had some muscle incorporated into the doughnut, compared with only one of 11 of the unaffected patients (p=0.012, Fisher's exact test). No other significant differences in operative variables were identified between patients with and without symptoms. INTERPRETATION: Persistent severe pain and faecal urgency has been found in a disturbingly high proportion of patients after stapled haemorrhoidectomy. The mechanism behind this phenomenon is unclear, although muscle incorporation in the doughnut may have a role. Other groups who have studied stapled haemorrhoidectomy urgently need to audit their long-term results to assess the frequency of this problem.

Mutations in the N-terminus of the X-linked retinitis pigmentosa protein RP2 interfere with the normal targeting of the protein to the plasma membrane.

The X-linked retinitis pigmentosa (XLRP) gene, RP2, codes for a novel 350 amino acid protein of unknown function. We have identified putative sites for N-terminal acyl modification by myristoylation and palmitoylation in the RP2 protein. The RP2 protein is expressed ubiquitously in human tissues at relatively low levels (0.01% of total protein) and has a predominantly plasma membrane localization in cultured cells, as would be expected if the protein was subject to dual N-terminal acylation. Furthermore, mutagenesis of residues potentially required for N-terminal acylation prevents targeting of RP2 to the plasma membrane and the N-terminal 15 amino acids of the protein appear to be sufficient for this targeting. Our data suggest that the protein is dually acylated and that the palmitoyl moiety is responsible for targeting of the myristoylated protein from intracellular membranes to the plasma membrane. The effect of two mutations, which have been reported as causes of XLRP, R118H and DeltaS6, were investigated. The R118H mutation does not affect the normal plasma membrane localization of RP2; in contrast, the DeltaS6 mutation interferes with the targeting of the protein to the plasma membrane. Therefore, the DeltaS6 mutation may cause XLRP because it prevents normal amounts of RP2 reaching the correct cellular locale, whereas the R118H mutation is in a region of the protein that is vital for another aspect of RP2 function in the retina.

Domain requirements of DnaJ-like (Hsp40) molecular chaperones in the activation of a steroid hormone receptor.

DnaJ-like proteins function in association with Hsp70 molecular chaperones to facilitate protein folding. We previously demonstrated that a yeast DnaJ-like protein, Ydj1p, was important for activation of heterologously expressed steroid hormone receptors (Caplan, A. J., Langley, E., Wilson, E. M., and Vidal, J. (1995) J. Biol. Chem. 270, 5251-5257). In the present study, we analyzed Ydj1p function by assaying hormone binding to the human androgen receptor (AR) heterologously expressed in yeast. We analyzed hormone binding in strains that were wild type or deleted for the YDJ1 gene. In the deletion mutant, the AR did not bind hormone to the same extent as the wild type. Introduction of mutant forms of Ydj1p to the deletion strain revealed that the J-domain is necessary but not sufficient for Ydj1p action, and that other domains of the protein are also functionally important. Of three human DnaJ-like proteins introduced into the deletion mutant, only Hdj2, which displays full domain conservation with Ydj1p, suppressed the hormone binding defect of the deletion mutant. By comparison of the domains shared by these three human proteins, and with mutants of Ydj1p that were functional, it was deduced that the cysteine-rich zinc binding domain is important for Hdj2/Ydj1p action in hormone receptor function. A model for the mechanism of DnaJ-like protein action is discussed.