EP.WE.205Impact of the Covid-19 Pandemic on Loop Ileostomy Formation

Aim

Uncertainty during the early phases of the Covid-19 pandemic regarding availability of critical care beds and peri-operative impact of SARS-CoV-2 led to changing intercollegiate guidance in favour of increased stoma formation. This study assessed the impact the Covid-19 pandemic had on loop ileostomy formation.

Methods

Data were reviewed from a prospectively collected database on the number of loop ileostomies formed over a 10-month period from 1^st March to 31^st December 2020. Comparison was made with the same period in 2019. Details were confirmed using clinical letters.

Results

114 loop ileostomies were formed in the 20-month period. There was a 10.0% reduction in loop ileostomy formation in 2020 compared with 2019. The median number of loop ileostomies formed per month over the two 10-month periods was 6. This peaked at 11 in April 2020 coinciding with the first wave of Covid-19, falling in subsequent months. All 11 of these loop ileostomies were formed in colorectal cancer patients undergoing anterior resection, after appropriate counselling.

Conclusions

There was a reduction in the number of ileostomies formed in 2020 compared with 2019 reflecting the impact of the Covid-19 pandemic on both elective and emergency case load and presentations. These results show reactive change in surgical practice corresponding to guidance at a time of maximum uncertainty. Primary anastomosis still occurred but with an increased likelihood of a defunctioning stoma to minimise the consequences of an anastomotic leak. A subsequent reduction in stoma formation in the following months indicates that practice rapidly returned to normal.

Evaluation of a confocal Raman probe for pathological diagnosis during colonoscopy

AIM

Raman spectroscopy of human tissue can provide a unique biochemical 'fingerprint' that alters with disease progression. Light incident on tissue is scattered and may be altered in wavelength, which can be represented as a Raman spectrum. A confocal fibreoptic Raman probe designed to fit down the accessory channel of a colonoscope has been constructed. This in-vitro study evaluated the accuracy of pathological diagnosis in the colon using probe-based Raman spectroscopy.

METHOD

Biopsy samples were collected at colonoscopy, snap frozen and stored at -80 °C. Raman spectra with 10-s and 1-s acquisition periods were measured with the probe tip in contact with the mucosal surface of thawed specimens. Mathematical modelling using principal component analysis followed by linear discriminant analysis was used to correlate Raman spectra with histopathological diagnoses.

RESULTS

Three-hundred and seventy-five Raman spectra were measured from a total of 356 colon biopsies (81 of normal colon mucosa, 79 of hyperplastic polyps, 92 of adenomatous polyps, 64 of adenocarcinoma and 40 of ulcerative colitis) from 177 patients. Spectral classification accuracies comparing pathology pairs ranged from 72.1 to 95.9% for 10-s acquisitions and from 61.5 to 95.1% for 1-s acquisitions. For a three-group model of normal, adenomatous and adenocarcinoma tissue, accuracies were 74.1% for 10-s acquisitions and 63.5% for 1-s acquisitions.

CONCLUSION

The confocal Raman probe system can distinguish between different colorectal pathologies. The probe has potential to establish Raman spectroscopy as a clinical tool for instant diagnosis at colonoscopy.

Perforated jejunal ulcer associated with gastric mucosa in a jejunal diverticulum

Jejunal diverticula are rare and subsequent complications even more so. The usual small bowel diverticulum encountered by general surgeons is a Meckel’s. These are embryological remnants of the vitello-intestinal duct and are on the anti-mesenteric surface of the terminal ileum. They may contain heterotopic gastric or pancreatic mucosa. Herein we explore the case of a young girl who presented with features of peritonitis secondary to a complication from a jejunal diverticulum. The case, pathology, complications and treatment of jejunal diverticulosis and heterotopic gastric mucosa in the jejunum are explored.

Modeling the clinical phenotype of BTK inhibition in the mature murine immune system

Inhibitors of Bruton's tyrosine kinase (BTK) possess much promise for the treatment of oncologic and autoimmune indications. However, our current knowledge of the role of BTK in immune competence has been gathered in the context of genetic inactivation of btk in both mice and man. Using the novel BTK inhibitor PF-303, we model the clinical phenotype of BTK inhibition by systematically examining the impact of PF-303 on the mature immune system in mice. We implicate BTK in tonic BCR signaling, demonstrate dependence of the T3 B cell subset and IgM surface expression on BTK activity, and find that B1 cells survive and function independently of BTK. Although BTK inhibition does not impact humoral memory survival, Ag-driven clonal expansion of memory B cells and Ab-secreting cell generation are inhibited. These data define the role of BTK in the mature immune system and mechanistically predict the clinical phenotype of chronic BTK inhibition.

Two week rule referral for patients with colorectal cancer below the age of 50; are we being ageist?

OBJECTIVES

The TWR system was introduced in July 2000. The purpose of this study was to investigate whether patients below the age of 50 years with colorectal cancer (CRC) are experiencing delays in treatment.

METHODS

The CRC database was searched for all newly diagnosed colorectal cancers between January 2001 and December 2005 in patients who were aged less than 50 years.

RESULTS

There were 911 patients with CRC during the study period. Of these, 41 patients (4.5%) were aged under 50. Thirty-eight case notes were retrieved and reviewed; the median age was 47 years. Fourteen (37%) presented as an emergency, 9 (24%) via the TWR, 8 (21%) were non-TWR referrals to outpatients and the remainder were referred via miscellaneous routes. The median time from referral to initial consultation was 11 days (range 8-14 days) in the TWR group, 24 days (range 14-135 days) in the surgical outpatients group and 44 days (range 11-93 days) in the miscellaneous (direct endoscopy, in-hospital physician's referral) group. The median time from referral to initiation of treatment was 51 days (range 15-116 days) in the TWR group, 103 days (range 43-174 days) in the outpatient group and 96 days (range 27-270 days) in the miscellaneous group. Excluding age as a factor, 73% of the non-TWR referrals met the TWR criteria.

CONCLUSION

Patients with symptoms of CRC below the age of 50 years may face referral and diagnostic delay if not referred via the TWR system; many of these would be eligible if age was not a deciding factor.

Undertaking procedure-based assessment is feasible in clinical practice

INTRODUCTION

With the development of a new curriculum, workplace based assessments such as procedure-based assessment (PBA) are becoming increasingly common within surgical training. However, there have been concerns about the impact of these assessments on clinical practice. This study assessed the time taken to complete PBA forms to determine whether it is feasible in clinical practice.

MATERIALS AND METHODS

PBAs for three colorectal procedures (anterior resection, right hemicolectomy and anal fistula) were undertaken by various trainers and trainees. A pilot study was performed to identify potential reasons for incomplete forms and procedural modifications subsequently applied in the main study. Times taken to complete the consenting and operative components of the forms were recorded.

RESULTS

Incomplete forms in the pilot were mainly attributable to time constraints. In the main study, all assessments were completed within 30 min. Assessment times increased with complexity of the procedure. Median times for completing the consenting and operative components in anterior resection were 13 min (range, 8-15 min) and 15 min (range, 10-18 min), respectively.

CONCLUSIONS

PBAs are feasible in clinical practice and are valued by trainees as a means of enabling focused feedback and targeted training. Commitment from trainers and trainees will be required but, with adequate planning, the assessment tool is effective with minimal impact on clinical practice.

Optical adjuncts for enhanced colonoscopic diagnosis

Background

Optical techniques using previously unexploited properties of light interaction with tissue may be valuable in the detection, diagnosis and staging of colorectal neoplasia.

Methods

A Medline search (1990 to present) was conducted on optical diagnostics in the detection of colorectal neoplasia. The reference list of each identified article was reviewed for further relevant papers.

Results and conclusion

Chromoendoscopy is the only optical adjunct to colonoscopy that has been tested in large randomized clinical trials. It improves the detection of small and flat colorectal adenomas, and of neoplasia in chronic ulcerative colitis and hereditary non-polyposis colorectal cancer. All other techniques are the subject of ongoing research and the practicality of population screening with any of the methods has yet to be established. Optical techniques may, however, permit immediate clinical diagnosis, removing the need for histological analysis. They may also improve the diagnosis of early colonic neoplasia.

Bowel function following insertion of self-expanding metallic stents for palliation of colorectal cancer

OBJECTIVE

Self-expanding metallic stents (SEMS) are an important addition to the treatment of large bowel obstruction. The aim of this study was firstly to assess bowel function following SEMS placement and secondly to identify any potential factors which might aid in the prediction of technical failure of stent insertion.

METHODS

A review of all patients undergoing attempted SEMS placement for palliation of malignant left-sided colorectal obstruction over a four-year period (1st May 2000-30th April 2004) was performed.

RESULTS

Twenty-one patients (12 male) with a median age of 76 years (range 48-92 years) were included, 11 with metastatic disease and 10 severe comorbidity. SEMS insertion was technically successful in 16 (76%) of 21 cases. Contrast successfully passed through the obstructing lesion in all 16 cases where SEMS placement was technically successful. It only passed through 1 of 5 cases where stenting was not possible (P = 0.0008, Fisher's Exact test). Complications included colonic perforation (1 case), stent migration (1 case) and tumour ingrowth requiring a second stent (1 case). Median survival after SEMS was 12 months (range 1-30 months), and 9 patients died during follow-up. Median bowel frequency following SEMS was 3.5 times per day (range 1-7). Eight patients always passed a liquid stool, 3 others regularly required laxatives and one further patient with poor function after stenting requested a defunctioning stoma.

CONCLUSION

Failure of contrast to pass through the obstructing lesion may predict those cases where stenting will not be technically possible. Median survival following SEMS insertion is encouraging in this series, but bowel function is often poor. Expected bowel function should be discussed fully when consenting patients for a SEMS, particularly those with metastatic disease who are otherwise fit for resectional surgery.

Emerging perceptions of facial plastic surgery among medical students

OBJECTIVE

The purpose of this study was to examine the perceptions of medical students regarding facial aesthetic surgery and those specialists most likely to perform aesthetic or reconstructive facial surgery.

METHODS

A survey was designed based on a review of the literature to assess the desirable characteristics and the perceived role of the facial plastic and reconstructive surgeon (FPRS). The surveys were distributed to 2 populations: medical students from 4 medical schools and members of the general public.

RESULTS

A total of 339 surveys were collected, 217 from medical students and 122 from the general public. Medical students and the public had similar responses. The results demonstrated that respondents preferred a male plastic surgeon from the ages of 41 to 50 years old and would look to their family doctor for a recommendation. Facial aesthetic and reconstructive surgery was considered the domain of maxillofacial and general plastic surgeons, not the FPRS.

CONCLUSION

Integration of the FPRS into the medical school curriculum may help to improve the perceived role of the specialty within the medical community. It is important for the specialty to communicate to aspiring physicians the dedicated training of an otolaryngologist specializing in FPRS.

mDia mediates Rho-regulated formation and orientation of stable microtubules

Rho-GTPase stabilizes microtubules that are oriented towards the leading edge in serum-starved 3T3 fibroblasts through an unknown mechanism. We used a Rho-effector domain screen to identify mDia as a downstream Rho effector involved in microtubule stabilization. Constitutively active mDia or activation of endogenous mDia with the mDia-autoinhibitory domain stimulated the formation of stable microtubules that were capped and oriented towards the wound edge. mDia co-localized with stable microtubules when overexpressed and associated with microtubules in vitro. Rho kinase was not necessary for the formation of stable microtubules. Our results show that mDia is sufficient to generate and orient stable microtubules, and indicate that Dia-related formins are part of a conserved pathway that regulates the dynamics of microtubule ends.

The pharmacology of the internal anal sphincter and new treatments of ano-rectal disorders

Surgical options for faecal incontinence in the presence of intact sphincters are limited. Furthermore, in patients with fissures, lateral sphincterotomy reduces anal sphincter hypertonia but there has been concern about complications. A greater understanding of the basic pharmacology of the internal anal sphincter has led to the development of novel treatments for both these disorders. A Medline review was undertaken for internal anal sphincter pharmacology, anal fissures and faecal incontinence. This review is based on these articles and those found by further cross-referencing. Nitric oxide released from non-adrenergic non-cholinergic nerves is the main inhibitory agent in the internal anal sphincter. Relaxations are also mediated through beta-adrenoceptors and muscarinic receptors. Stimulation of alpha-receptors results in contraction. Calcium and its entry through L-type calcium channels is important for the maintenance of tone. Nitric oxide donors produce reductions in resting anal tone and heal fissures but are associated with side-effects. Muscarinic agents and calcium channel antagonists show promise as low side-effect alternatives. Botulinum toxin appears more efficacious than other agents in healing fissures. To date, alpha-receptor agonists have been disappointing at improving incontinence. Further understanding of the pharmacology of the internal anal sphincter may permit the development of new agents to selectively target the tissue with greater efficacy and fewer side-effects.

The delta subunit of type 6 phosphodiesterase reduces light-induced cGMP hydrolysis in rod outer segments

The delta subunit of the rod photoreceptor PDE has previously been shown to copurify with the soluble form of the enzyme and to solubilize the membrane-bound form (). To determine the physiological effect of the delta subunit on the light response of bovine rod outer segments, we measured the real time accumulation of the products of cGMP hydrolysis in a preparation of permeablized rod outer segments. The addition of delta subunit GST fusion protein (delta-GST) to this preparation caused a reduction in the maximal rate of cGMP hydrolysis in response to light. The maximal reduction of the light response was about 80%, and the half-maximal effect occurred at 385 nm delta subunit. Several experiments suggest that this effect was not due to the effects of delta-GST on transducin or rhodopsin kinase. Immunoblots demonstrated that exogenous delta-GST solubilized the majority of the PDE in ROS but did not affect the solubility of transducin. Therefore, changes in the solubility of transducin cannot account for the effects of delta-GST in the pH assay. The reduction in cGMP hydrolysis was independent of ATP, which indicates that it was not due to effects of delta-GST on rhodopsin kinase. In addition to the effect on cGMP hydrolysis, the delta-GST fusion protein slowed the turn-off of the system. This is probably due, at least in part, to an observed reduction in the GTPase rate of transducin in the presence of delta-GST. These results demonstrate that delta-GST can modify the activity of the phototransduction cascade in preparations of broken rod outer segments, probably due to a functional uncoupling of the transducin to PDE step of the signal transduction cascade and suggest that the delta subunit may play a similar role in the intact outer segment.

Binding of the delta subunit to rod phosphodiesterase catalytic subunits requires methylated, prenylated C-termini of the catalytic subunits

PDE6 (type 6 phosphodiesterase) from rod outer segments consists of two types of catalytic subunits, alpha and beta; two inhibitory gamma subunits; and one or more delta subunits found only on the soluble form of the enzyme. About 70% of the phosphodiesterase activity found in rod outer segments is membrane-bound, and is thought to be anchored to the membrane through C-terminal prenyl groups. The recombinant delta subunit has been shown to solubilize the membrane-bound form of the enzyme. This paper describes the site and mechanism of this interaction in more detail. In isolated rod outer segments, the delta subunit was found exclusively in the soluble fraction, and about 30% of it did not coimmunoprecipitate with the catalytic subunits. The delta subunit that was bound to the catalytic subunits dissociated slowly, with a half-life of about 3.5 h. To determine whether the site of this strong binding was the C-termini of the phosphodiesterase catalytic subunits, peptides corresponding to the C-terminal ends of the alpha and beta subunits were synthesized. Micromolar concentrations of these peptides blocked the phosphodiesterase/delta subunit interaction. Interestingly, this blockade only occurred if the peptides were both prenylated and methylated. These results suggested that a major site of interaction of the delta subunit is the methylated, prenylated C-terminus of the phosphodiesterase catalytic subunits. To determine whether the catalytic subunits of the full-length enzyme are methylated in situ when bound to the delta subunit, we labeled rod outer segments with a tritiated methyl donor. Soluble phosphodiesterase from these rod outer segments was more highly methylated (4.5 +/- 0.3-fold) than the membrane-bound phosphodiesterase, suggesting that the delta subunit bound preferentially to the methylated enzyme in the outer segment. Together these results suggest that the delta subunit/phosphodiesterase catalytic subunit interaction may be regulated by the C-terminal methylation of the catalytic subunits.

Abnormal contractile properties of rectal smooth muscle in chronic ulcerative colitis

BACKGROUND

Patients with ulcerative colitis have abnormal rectal motility.

AIM

To compare the contractile properties of rectal smooth muscle from patients with ulcerative colitis and controls.

METHODS

Rectal smooth muscle strips from patients undergoing resection for ulcerative colitis or cancer (control) were mounted in an organ bath. The effects of carbachol (receptor-mediated) and potassium (causes membrane depolarization) were studied. Acetylcholinesterase histochemistry was performed and nerve counts compared.

RESULTS

Ulcerative colitis (n=41) and control (n=34) strips contracted in response to potassium and carbachol. Mean (S.E. M.) maximum response to potassium in the control and ulcerative colitis groups was 1.07 (0.06) g/mg and 1.02 (0.09) g/mg tissue, respectively (P=N.S.). EC50s (concentrations required to give 50% of maximal response) were 75 (1) mM and 73 (1) mM, respectively (P=N.S. ). Although maximum responses to carbachol were similar, 2.12 (0.12) g/mg and 1.95 (0.12) g/mg tissue (P=N.S.), ulcerative colitis strips exhibited an increased sensitivity to carbachol, EC50s: 5.05 x 10-6 (0.55 x 10-6) M vs. 8.36 x 10-6 (0.88 x 10-6) M, P=0.002). There was no significant difference in nerve counts between the tissues, as assessed by staining for acetylcholinesterase.

CONCLUSIONS

Ulcerative colitis tissue has an increased sensitivity to carbachol and this is not due to denervation; it may result from increased calcium release from intracellular stores since contraction due to membrane depolarization is not altered. Modulation of this pathway could potentially be used to alter rectal motility in patients with ulcerative colitis.

Percutaneous endoscopic gastrostomy at the time of tumour resection in advanced oral cancer

The role of percutaneous endoscopic gastrostomy (PEG) in patients undergoing resection of head and neck malignancy is well established. The procedure may be performed pre- or post-operatively with intravenous sedation or alternatively under general anaesthesia at the time of tumour resection. There are concerns as to the safety of PEG, particularly when performed under intravenous sedation. Elderly patients with poor general health and those with airway compromise may be at significant risk. We believe that patients with advanced oral malignancy often fall into such groups and, therefore, we routinely perform PEG at the time of resection. The aim of this study was to determine the potential risk factors for PEG insertion in patients with advanced oral malignancy and present our experience with insertion at the time of resection. A retrospective study was undertaken of the risk factors for PEG insertion in 72 consecutive patients with stage IV oral cancer treated between April 1993 and March 2000. Age, sex, tumour site, past medical history, American Society of Anaesthesiologists (ASA) and laryngoscopy grade, as an assessment of potential airway compromise, were recorded. There were 72 patients, 40 males and 32 females, with a mean age of 63 years (27-90). Eighteen patients (25%) scored 3 or 4 on the ASA scores of physical status. Laryngoscopy grades were recorded in 65 patients; of these, 18 (25%) had reduced visualisation of the larynx and in two patients not even the epiglottis could be seen. It is concluded that patients with advanced oral cancer have significant risk factors for PEG placement. However, PEG can be safely performed at the time of ablative surgery and has the advantage of avoiding an additional operative event for the patient.

Bipolar scissors in facial plastic surgery

BACKGROUND

Many methods are available to the facial plastic surgeon for elevating and separating tissue, from cold steel to monopolar cautery to various laser-cutting technologies. Bipolar cautery has replaced monopolar cautery as the optimal hemostatic technique because of its decreased tissue damage and improved capabilities. Bipolar scissors concurrently offer a dissecting technique with hemostatic capability. Little exists in the otolaryngology literature on the use of bipolar scissors for soft tissue dissection.

OBJECTIVE

To describe our experience using bipolar scissors in a variety of facial plastic and reconstructive procedures.

SETTING

Tertiary care referral academic center.

DESIGN

We retrospectively reviewed 78 procedures performed using bipolar scissors between June 1997 and August 1999. In facial plastic cosmetic surgery, bipolar scissors were used 31 times for deep plane face-lifts and 16 times for endoscopic browlifts. In facial plastic reconstructive surgery, bipolar scissors were used in 15 radial forearm free flaps, 10 fibula osteocutaneous flaps, 3 rectus abdominis free flaps, and 3 latissimus dorsi myocutaneous free flaps.

RESULTS

In all procedures, bipolar scissors facilitated the dissection. By allowing for a drier field, less time was required to elevate the flap and obtain hemostasis. Complications were not increased compared with historical controls. In the harvesting of fibula osteocutaneous free flaps, use of bipolar scissors allowed harvesting without use of a tourniquet.

CONCLUSION

Bipolar scissors, a new technology in facial plastic surgery, allow the same control as sharp dissection and provide simultaneous hemostasis.

Decreased splatter in dermabrasion

OBJECTIVE

To compare a new dermabrasion instrument equipped with a metal shield and hydration-suction apparatus with the standard instrument, with specific attention to the exposure of operating room personnel to potentially hazardous particles.

DESIGN

A surgical trial with each of the instruments was performed with a skin model. The splatter caused by the 2 instruments was evaluated and compared statistically and graphically.

SUBJECTS

Female hairless guinea pigs (450 g) were used as a skin model.

INTERVENTIONS

Ten guinea pigs were treated with the standard dermabrading instrument, and 10 were treated with a shielded suction-irrigating dermabrader. The splatter was analyzed by counting the number of particles landing on strategically placed glass slides. Evaluations of histologic cross-sections of the dermabraded skin were compared in a blinded fashion.

RESULTS

Statistical and graphic analysis showed the number of potentially hazardous particles generated by the suction dermabrader to be significantly less than that generated by the standard dermabrader. Histologic sections showed no difference between the 2 subsets.

CONCLUSION

The new shielded suction-irrigating dermabrader provides comparable surgical results while significantly decreasing exposure to potentially hazardous splatter particles. Arch Facial Plast Surg. 2000;2:23-26

Oral nifedipine reduces resting anal pressure and heals chronic anal fissure

BACKGROUND

Topical preparations have been used in the treatment of anal fissure. However, they are not universally successful and there is confusion over the site and dose of application. This study assessed the effectiveness of oral nifedipine in reducing resting anal pressure and on fissure healing.

METHODS

Anal manometry was performed on eight healthy volunteers and 15 patients with chronic anal fissure before and after oral administration of nifedipine 20 mg. Nifedipine was taken twice daily. Fissure healing was assessed over an 8-week period and pain scores were monitored.

RESULTS

Oral nifedipine produced an initial reduction in maximum resting anal pressure (MRP) of 35 per cent (P < 0.001) and of 28 per cent after 5 days (P < 0.001) in healthy volunteers. A reduction in MRP of 36 per cent (P < 0.001) was observed in patients with fissure. Pain scores were significantly reduced during the treatment period. Healing was complete in nine patients after 8 weeks and a further three were asymptomatic. Ten patients experience flushing and four had mild headaches. There were no episodes of postural hypotension or incontinence.

CONCLUSION

Oral nifedipine reduces resting anal pressure. It is well tolerated and offers an alternative treatment for chronic anal fissure.

A 3-year multi-institutional experience with the liposhaver

OBJECTIVE

To report a 3-year multi-institutional clinical experience with the liposhaver in facial plastic surgery.

DESIGN

Nonrandomized, nonblinded, multi-institutional evaluation of the liposhaver in a clinical setting.

INTERVENTIONS

Seventy-two patients who presented for facial plastic surgical procedures underwent surgery with the liposhaver. Seventy-six liposhaving procedures and 74 concomitant procedures were performed. Standardized preoperative and postoperative photographs were obtained.

OUTCOME MEASURE

Subjective evaluation by the surgeons who performed the procedures.

RESULTS

The liposhaver was used successfully in all cases. The fat was cleanly shaved and the contour results were even, without dimpling or significant asymmetry. Operative time was comparable to that of conventional liposuction. There were no cases of facial nerve injury and no evidence of increased bleeding intraoperatively. Two male patients had small postoperative hematomas in the immediate postoperative period that were successfully treated with conservative measures. An additional patient developed a small hematoma on postoperative day 5 that was effectively treated with needle aspiration and a pressure dressing.

CONCLUSION

This 3-year multi-institutional report suggests that the liposhaver continues to offer a precise alternative to conventional liposuction.

Closure of a scalp defect

In repairing cutaneous defects, the facial plastic and reconstructive surgeon is faced with many specialized areas of tissue. Reconstruction of thin eyelid skin and thick, sebaceous nasal skin requires different methods. The unique characteristics of the scalp make it one of the greatest repair challenges in the head and neck region, sometimes requiring multiple different reconstructive techniques for the same defect.

cGMP binding to noncatalytic sites on mammalian rod photoreceptor phosphodiesterase is regulated by binding of its gamma and delta subunits

The binding of cGMP to the noncatalytic sites on two isoforms of the phosphodiesterase (PDE) from mammalian rod outer segments has been characterized to evaluate their role in regulating PDE during phototransduction. Nonactivated, membrane-associated PDE (PDE-M, alpha beta gamma2) has one exchangeable site for cGMP binding; endogenous cGMP remains nonexchangeable at the second site. Non-activated, soluble PDE (PDE-S, alpha beta gamma2 delta) can release and bind cGMP at both noncatalytic sites; the delta subunit is likely responsible for this difference in cGMP exchange rates. Removal of the delta and/or gamma subunits yields a catalytic alphabeta dimer with identical catalytic and binding properties for both PDE-M and PDE-S as follows: high affinity cGMP binding is abolished at one site (KD >1 microM); cGMP binding affinity at the second site (KD approximately 60 nM) is reduced 3-4-fold compared with the nonactivated enzyme; the kinetics of cGMP exchange to activated PDE-M and PDE-S are accelerated to similar extents. The properties of nonactivated PDE can be restored upon addition of gamma subunit. Occupancy of the noncatalytic sites by cGMP may modulate the interaction of the gamma subunit with the alphabeta dimer and thereby regulate cytoplasmic cGMP concentration and the lifetime of activated PDE during visual transduction in photoreceptor cells.

Effects of nifedipine on anorectal smooth muscle in vitro

INTRODUCTION

Glyceryl trinitrate reduces anal resting pressure and aids the healing of anal fissures. However, some patients develop tachyphylaxis and the fissure fails to heal, suggesting that other agents are needed. This study assesses the effects of nifedipine (a calcium channel antagonist) in modulating resting tone and agonist-induced contractions in human internal anal sphincter (IAS) and rectal circular muscle.

METHODS

Smooth muscle strips from the IAS and rectal circular muscle from ten patients undergoing surgical resection were mounted for isometric tension recording in a superfusion organ bath. The effects of noradrenaline and carbachol were assessed in the presence of various perfusates.

RESULTS

LAS strips developed tone and spontaneous activity. Noradrenaline produced dose-dependent contractions. In calcium-free Krebs solution, tone and activity were abolished and no contractions were elicited in response to noradrenaline. Nifedipine also abolished tone and spontaneous activity, but contractions to noradrenaline were only slightly attenuated. In contrast, rectal smooth muscle strips developed spontaneous activity but no resting tone and contracted in response to carbachol. In calcium-free Krebs solution, the spontaneous activity and carbachol contractions were abolished. Addition of nifedipine to the perfusate abolished spontaneous activity and greatly reduced contractions.

DISCUSSION

These data suggest that spontaneous activity and resting tone are dependent on extracellular calcium and flux across the cells. Agonist-induced contraction in the IAS is attributable mainly to the release of calcium from intracellular stores, whereas rectal circular smooth muscle depends principally on extracellular calcium entering the cell for contraction. The attenuation of contractions in both tissues and the abolition of resting tone in the IAS suggest that nifedipine may be useful in the management of patients with anorectal disorders.

Microtubules and signal transduction

Although molecular components of signal transduction pathways are rapidly being identified, how elements of these pathways are positioned spatially and how signals traverse the intracellular environment from the cell surface to the nucleus or to other cytoplasmic targets are not well understood. The discovery of signaling molecules that interact with microtubules (MTs), as well as the multiple effects on signaling pathways of drugs that destabilize or hyperstabilize MTs, indicate that MTs are likely to be critical to the spatial organization of signal transduction. MTs themselves are also affected by signaling pathways and this may contribute to the transmission of signals to downstream targets.

Differences in contractile properties of anorectal smooth muscle and the effects of calcium channel blockade

BACKGROUND

Pharmacological manipulation of the anal sphincter is hampered by a lack of specificity. This study aimed to determine differences in the role of intracellular and extracellular calcium in the development of tone and agonist-induced contractions between internal anal sphincter (IAS) and rectal circular muscle which might allow targeted manipulation.

METHODS

Smooth muscle strips from the IAS and rectal circular muscle of 24 Large White pigs were mounted for isometric tension recording in a superfusion organ bath in the presence of different perfusates.

RESULTS

IAS developed tone and spontaneous activity that were abolished by nifedipine, which also reduced contractions to noradrenaline to 72 per cent of control values. Rectal smooth muscle developed spontaneous activity but no tone. Nifedipine abolished the activity and reduced contractions to carbachol to 17 per cent of control. Contractile activity was abolished in both tissues in calcium-free solution. Transient exposure to a high calcium concentration reloaded the stores, and the ability of agonists to release stored calcium was tested after 3 min in calcium-free solution. In IAS, noradrenaline contraction was 76 per cent of control and in rectal circular muscle carbachol contraction was 57 per cent of control. Store loading was prevented by nifedipine in rectal smooth muscle but not IAS. Cyclopiazonic acid reduced store filling in both tissues.

CONCLUSION

Agonist-induced contraction of IAS is largely due to release of stored calcium and L-type calcium channels are not needed for store filling. Rectal circular smooth muscle depends more on extracellular calcium and uses L-type calcium channels for agonist-induced contraction and store filling. These differences suggest that targeted manipulation may be possible in patients with anorectal disorders.

Replantation of the amputated nose

OBJECTIVE

To assess the effectiveness of replantation in the treatment of nasal amputations.

DESIGN

Retrospective chart review.

SETTING

A university medical center.

RESULTS

In no case did the replant survive completely, and in all cases revision surgery was required. However, in all cases, the resulting deformity was less than the original defect. In our pediatric patients, reconstruction with cartilage grafting and a midline forehead flap was successful and demonstrated proportionate and appropriate growth.

CONCLUSIONS

It is our belief that replantation serves many therapeutic functions. At the very least, there is the psychological/emotional factor that is involved in attempting to replace a native body part that has been severed. Also, it is difficult to persuade parents and patients that the amputated tissue that has been handled with kid gloves by paramedics, maintaining its pink "alive" color, is ultimately doomed to failure. Forehead flaps and conchal cartilage grafts are more willingly accepted after a "failed" replantation than as primary reconstructions. In every instance, we believe, the ultimate defect will be smaller than the original deformity. Certainly, the need for vestibular lining reconstruction is far less. Thus, the ultimate healed defect from the replantation greatly facilitates final nasal reconstruction.

Rho guanosine triphosphatase mediates the selective stabilization of microtubules induced by lysophosphatidic acid

The asymmetric distribution of stable, posttranslationally modified microtubules (MTs) contributes to the polarization of many cell types, yet the factors controlling the formation of these MTs are not known. We have found that lysophosphatidic acid (LPA) is a major serum factor responsible for rapidly generating stable, detyrosinated (Glu) MTs in serum-starved 3T3 cells. Using C3 toxin and val14 rho we showed that rho was both necessary and sufficient for the induction of Glu MTs by LPA and serum. Unlike previously described factors that induce MT stability, rho induced the stabilization of only a subset of the MTs and, in wound-edge cells, these stable MTs were appropriately oriented toward the leading edge of the cell. LPA had little effect on individual parameters of MT dynamics, but did induce long states of pause in a subset of MTs near the edge of the cell. Rho stimulation of MT stability was independent of actin stress fiber formation. These results identify rho as a novel regulator of the MT cytoskeleton that selectively stabilizes MTs during cell polarization by acting as a switch between dynamic and stable states of MTs rather than as a modulator of MT assembly and disassembly.

Management of faecal incontinence following obstetric injury

BACKGROUND

Faecal incontinence is common in women and the major aetiological factor is childbirth. Increasing numbers of women with faecal incontinence are presenting to surgical clinics.

METHODS

A literature review was performed on Medline database for English language publications an obstetric injury. The incidence, presentation, assessment and treatment of faecal incontinence following obstetric injury were evaluated.

RESULTS AND CONCLUSIONS

Third-degree tear occurs in association with less than 1 per cent of vaginal deliveries, but occult sphincter injury occurs at one-third of deliveries and may be significant in later life. Incontinence may result from sphincter damage or nerve injury, or both. Risk factors for these injuries can be identified. Clinical evaluation, anorectal physiology and endoanal ultrasonography allow accurate planning of subsequent surgery. Overlapping anterior anal sphincter repair provides symptomatic control of continence in 80 per cent of patients. Repair of an acute anal sphincter injury after a third-degree tear is controversial and a defined policy should be agreed between obstetric and colorectal teams.

Protocol violation in deep vein thrombosis prophylaxis

This study aimed to determine how closely deep vein thrombosis (DVT) prophylactic policies are adhered to in routine general surgical practice, to identify reasons for policy violations and to assess the effects of policy modification. Eight adult patients, sixty of whom had undergone an operation, under the care of six general surgeons, each with their own written DVT protocol, were studied on one weekday. Thirty patients (50%) did not receive DVT prophylaxis according to the policy of the relevant consultant. Most violations occurred for unacceptable reasons, mainly starting low-dose subcutaneous heparin or using thromboembolic stockings postoperatively. However, 43% of protocol violations occurred for acceptable clinical reasons. Following the initial study, a uniform departmental DVT prophylaxis policy was introduced. Nursing and medical staff were thoroughly appraised of the new policy. In a repeat study of 75 patients 1 year later, there were 15 protocol violations among 58 patients who had undergone an operation (27%). However, there were no violations for acceptable reasons. The number of unacceptable protocol violations in the two studies was similar (24/60 and 17/56). The number of patients at moderate or high DVT risk who received no preoperative prophylaxis was the same in both studies (8/48 in both audits). DVT protocol violations are common in routine general surgical practice. Policy modification and unification results in fewer violations, but made little impact on the level of thromboprophylactic care.

Varicose vein clinics: modelling the effects of seasonal variation in referrals

Data have been collected prospectively on patients referred to a specialist varicose vein clinic between January 1991 and December 1994. A seasonal variation in referral pattern of patients is demonstrated, with more patients being referred in the summer months. Similar fluctuations are seen in the number of patients waiting for first appointment, and the average waiting time for first appointment. Such fluctuations in referral patterns can lead to difficulties in planning. A computer model has been constructed and used to predict future referrals and the effects of seasonal variations upon waiting times for appointments and on efficiency of clinic usage. The computer model accurately predicts numbers of future referrals. The average waiting time for first appointment could be kept constant by arranging more varicose vein clinics in summer than in winter but keeping the overall number of clinics during the year constant. The computer model could be important in planning of specialist clinics, and may play a role when negotiating future contracts. If flexibility can be achieved by exchanging clinics with different seasonal patterns, it may be possible to reduce waiting times within existing resources.

Reconstructive rhinoplasty

Reconstructive rhinoplasty for larger nasal defects requires a three-dimensional perspective using many of the aesthetic and functional techniques commonly employed in rhinoplasty. There are numerous ways of addressing a deficiency of the internal lining and each technique is detailed. Structural grafting is imperative in order to resist the contracture and collapse of the reconstructive nose. These grafts are also used to enhance contour and definition. Resurfacing of large cutaneous defects is frequently achieved through the midline forehead flap. There are many subtle maneuvers which can significantly impact the final aesthetic outcome and these are discussed below. This article highlights the three-layered approach to subtotal and total reconstructive rhinoplasty.

Quality of life changes after angioplasty for claudication: medium-term results affected by comorbid conditions

Rapid improvements in walking distance and quality of life have been identified in patients with intermittent claudication following percutaneous transluminal angioplasty, but the medium-term results are less well defined. The aim of this study was to assess quality of life and walking distance in the medium term. Walking distance was assessed before percutaneous transluminal angioplasty and at 6 weeks and 1 year after the procedure using a previously validated questionnaire. At the same time, quality of life was assessed using a EuroQol questionnaire and a visual analogue scoring system. Twenty-four patients (12 men, 12 women, mean age 65 years) underwent successful percutaneous transluminal angioplasty (five iliac, 17 femoropopliteal, two both). Significant improvements in walking distance and quality of life were demonstrated following percutaneous transluminal angioplasty. These were maintained at 1 year, although perceived health state deteriorated. During the study period, six patients developed other serious comorbidities. Development of comorbid conditions may affect the medium-term outcome of quality of life studies in patients treated for intermittent claudication. Data from such studies should therefore be interpreted with care.

Cartilage Viability with Interpolated Skin Flaps: An Experimental Study

Although composite cartilage grafts are often used in conjunction with a midline forehead flap to repair full-thickness nasal defects, the timing of pedicle division, which optimizes cartilage viability, has yet to be determined. A rabbit animal model was designed to investigate this question. The skin flap pedicle was divided at 0 days, 4 days, 3 weeks, 6 weeks, and 10 weeks in each of five groups of five animals. Although early pedicle division led to partial skin flap necrosis, the cartilage grafts tolerated this ischemic period better. Cartilage viability was approximately 70% and did not differ significantly between the five groups. It is concluded that a larger composite graft and better definition of the skin flap's critical period are needed to determine optimum timing for pedicle division in this animal model.

Cartilage viability with interpolated skin flaps: an experimental study

Although composite cartilage grafts are often used in conjunction with a midline forehead flap to repair full-thickness nasal defects, the timing of pedicle division, which optimizes cartilage viability, has yet to be determined. A rabbit animal model was designed to investigate this question. The skin flap pedicle was divided at 0 days, 4 days, 3 weeks, 6 weeks, and 10 weeks in each of five groups of five animals. Although early pedicle division led to partial skin flap necrosis, the cartilage grafts tolerated this ischemic period better. Cartilage viability was approximately 70% and did not differ significantly between the five groups. It is concluded that a larger composite graft and better definition of the skin flap's critical period are needed to determine optimum timing for pedicle division in this animal model.

Upregulation of dynamin II expression during the acquisition of a mature pancreatic acinar cell phenotype

Members of the dynamin superfamily are GTPases which have been shown to support receptor-mediated endocytosis in vivo and bind to growth factor receptor-associated proteins in vitro. In acinar cells of the pancreas, receptor-mediated endocytosis is very important for the recycling of membranes after secretory granule release. Therefore, characterization of the molecular machinery responsible for this process is critical for a better understanding of this phenomenon. In this study we sought to determine the expression pattern of the endocytic GTPase dynamin II during pancreatic acinar cell differentiation in developing rat embryos and in dexamethasone-treated AR42J cells using Western blot, Northern blot, and immunocytochemical analyses. During pancreatic development, dynamin immunoreactivity is almost undetectable until day E17 but undergoes significant upregulation in acinar cells starting at E18. In addition, the levels of dynamin mRNA and protein in AR42J cells increase approximately threefold during dexamethasone-induced acinar differentiation. The increase in dynamin levels that occurs in both embryonic pancreatic cells and dexamethasone-treated AR42J cells correlates with the establishment of a more differentiated acinar phenotype. Therefore, these results suggest a potential role for dynamin in supporting receptor-mediated endocytosis in mature pancreatic acinar cells.

The liposhaver in facial plastic surgery. A multi-institutional experience

OBJECTIVE

To report a multi-institutional clinical experience with the liposhaver in facial plastic surgery.

DESIGN

Nonrandomized, nonblinded, multi-institutional evaluation of the liposhaver in a clinical setting in patients presenting for cosmetic facial liposuction.

INTERVENTIONS

Cosmetic facial surgery with the liposhaver was performed in 19 patients (21 procedures) who underwent submental lipectomy, facelift with defatting beneath the facelift flap, and/or correction of deep nasolabial folds. Standardized preoperative and postoperative photographs were obtained. Fat obtained from the abdomen of 1 patient was also studied histologically. This fat was excised sharply and was then liposhaved at varying oscillation speeds.

OUTCOME MEASURES

Subjective evaluation by the operating surgeons.

RESULTS

The liposhaver was used successfully in all cases. The fat was cleanly shaved and the contour results were even, without dimpling or asymmetry. Operative time was comparable to that for conventional liposuction. Preferred cannula sizes and settings were determined. There were no cases of facial nerve injury, no evidence of increased bleeding intraoperatively, and no hematomas in the immediate postoperative period. One patient developed a small hematoma on postoperative day 5 that was effectively treated with needle aspiration and a pressure dressing. Histologic evaluation of liposhaved abdominal fat showed normal fat cells and well-preserved architecture.

CONCLUSIONS

The liposhaver offers a precise alterative to conventional liposuction. It may be less traumatic because it requires low suction pressures and does not rely on the potentially bruising, vigorous, back-and-forth motion for fat extraction typical of conventional liposuction.

Port-site metastases in patients undergoing laparoscopy for gastrointestinal malignancy

Laparoscopic colonic resection and laparoscopy for the assessment of malignant disease have been advocated. Metastatic deposits at port sites are recognized but the incidence of these is poorly defined. Forty-six patients, of median age 65 (range 19-90) years, with gastrointestinal malignancy underwent laparoscopy. Eighteen patients died a median of 4 (range 1-28) months after laparoscopy, four following colonic resection and 14 with gastro-oesophageal malignancy; ten had undergone resection. Median follow-up of the 28 survivors is 8 (range 2-39) months. Five of the 46 patients developed port-site recurrence giving an early incidence of port-site recurrence in this cohort of patients of 11 per cent. Five of 20 patients with tumour involving serosal surfaces developed port-site recurrence compared with none of 26 without serosal involvement (P = 0.022, Fisher's exact test). Port-site recurrence may be related to serosal involvement with tumour.

Use of covered expandable metal stents in the treatment of oesophageal carcinoma and tracheo-oesophageal fistula

Palliation for malignant dysphagia has relied on oesophageal dilatation, insertion of rigid prostheses and laser treatment. All three methods have substantial risk of perforation. Displacement of the tube is also well described. Seventeen expandable polyethylene-covered metal stents were inserted in 15 patients with oesophageal carcinoma; there were 11 men and four women, of median age 70 years. Thirteen stents were inserted for dysphagia and four for tracheo-oesophageal fistula (TOF). Stents were inserted endoscopically under fluorosopic control. Seven patients died from their disease a median of 5 (range 1-11) months after stent insertion. Median follow-up in the remainder is 6 (range 1-11) months. Median dysphagia scores before and after insertion were 3 (range 2-4) and 1 (range 1-2) respectively. Stent insertion provided cure of symptoms in patients with TOF. Median hospital stay following insertion was 2 (range 1-20) nights. There were no deaths and no perforations associated with the procedure. Two patients complained of retrosternal chest pain for 2 days after stent insertion. One patient presented with dysphagia related to later stent migration. There has been no deterioration in symptoms of dysphagia in the remainder. Expandable oesophageal stents offer a safe alternative to traditional methods of palliative treatment for oesophageal carcinoma. In the long term they may provide a cost-effective alternative to standard treatments.

A prospective study to define the optimum rescreening interval for small abdominal aortic aneurysm

A prospective study of 99 patients with small abdominal aortic aneurysms was undertaken using serial ultrasound to assess the optimum screening interval. Fifty-three patients had aneurysms measuring 2.5-3.9 cm and 46 patients aneurysms of 4.0-4.9 cm. Aneurysms measuring 2.5-3.9 cm were screened annually and those > 4.0 cm every 6 months. There were eight deaths in the 2.5-3.9 cm group, none attributable to a ruptured aneurysm and five patients have had their aneurysm repaired. Nine patients died in the 4.0-4.9 cm group, one with a ruptured aneurysm measuring 5.6 cm at her previous screening visit and who was unfit for operation. No other patient had an aneurysm which ruptured between scans. There were seven elective repairs in this group. No patient died following elective operation in either group. The mean growth rate of aneurysms in the 2.5-3.9 cm group was 2.2 mm in the first year, 2.8 mm in the second and 1.8 mm in the third. Corresponding growth rates in the 4.0-4.9 cm group were 2.7 mm, 4.2 mm and 2.2 mm. This study supports a policy of annual screening for aneurysms measuring 2.5-3.9 cm and 6-monthly screening for those > or = 4.0 cm.

Rejuvenation of the aging forehead and brow

Rejuvenation of the aging upper face can transform tired and angry features into youthful-appearing ones. This article presents the principles for analyzing and treating the aging forehead and brow. The esthetic dimensions and proportions of the brow and forehead are discussed, in context with the corresponding surgical anatomy. The goals of facial rejuvenation surgery as it relates to the upper third of the face are addressed. Various approaches, including their advantages and disadvantages, are presented. The appropriate approach is selected to eliminate unsightly features that are in need of correction while minimizing hairline shifts and forehead scarring and anesthesia. Following the principles and techniques illustrated in this article, the facial plastic surgeon may confidently treat the signs and complaints of the aging upper face.

The rat ventral island flap: a comparison of the effects of reduction in arterial inflow and venous outflow

The relative importance of reduced arterial inflow versus reduced venous outflow in determining flap necrosis remains undefined, even though this is critically important in understanding the effects of pharmacologic agents on flap survival. By means of a rat bipedicled ventral island flap, the amount of random flap necrosis was examined in four experimental groups: (1) unilateral arteriovenous ligation (n = 19), (2) unilateral vein ligation (n = 20), (3) unilateral artery ligation (n = 20), and (4) alternate side vein and artery ligation (n = 18). No necrosis occurred on the side of the vein ligation in groups 2 and 4, indicating that independently reducing venous outflow does not cause flap necrosis. A predictable necrosis occurred ipsilateral to artery ligation in groups 1 (37.63 +/- 17.34 percent), 3 (32.74 +/- 17.32 percent), and 4 (15.70 +/- 9.86 percent). These data indicate that the rat ventral island flap is more sensitive to a decrease in arterial inflow than to a decrease in venous outflow. This model may therefore be useful in clarifying the effect and determining the mechanism of action of pharmacologic agents that alter flap survival.

Magnetic resonance imaging in the management of diabetic foot infection

A prospective study was carried out of 22 patients admitted with 25 diabetic foot infections. All had cellulitis, 12 had discharging ulcers and eight had digital gangrene. In one case magnetic resonance imaging (MRI) was unhelpful owing to patient movement. Thirteen scans suggested deep-seated infection, including abscess (ten), osteomyelitis (seven) and ankle effusion (one). Overall, imaging provided a specificity of 77 per cent, a positive predictive value of 77 per cent, a sensitivity of 91 per cent and a negative predictive value of 91 per cent. MRI is valuable in determining the presence and extent of infection, which allows appropriate planning of surgical intervention.