The antiproliferative effect of FGF2 in K-Ras-driven tumor cells involves modulation of rRNA and the nucleolus

The nucleolus is sensitive to stress and can orchestrate a chain of cellular events in response to stress signals. Despite being a growth factor, FGF2 has antiproliferative and tumor-suppressive functions in some cellular contexts. In this work, we investigated how the antiproliferative effect of FGF2 modulates chromatin-, nucleolus- and rDNA-associated proteins. The chromatin and nucleolar proteome indicated that FGF2 stimulation modulates proteins related to transcription, rRNA expression and chromatin-remodeling proteins. The global transcriptional rate and nucleolus area increased along with nucleolar disorganization upon 24 h of FGF2 stimulation. FGF2 stimulation induced immature rRNA accumulation by increasing rRNA transcription. The rDNA-associated protein analysis reinforced that FGF2 stimulus interferes with transcription and rRNA processing. RNA Pol I inhibition partially reversed the growth arrest induced by FGF2, indicating that changes in rRNA expression might be crucial for triggering the antiproliferative effect. Taken together, we demonstrate that the antiproliferative FGF2 stimulus triggers significant transcriptional changes and modulates the main cell transcription site, the nucleolus.

Abstract 2135: Targeting N-Myc in neuroblastoma cells with selective Aurora kinase A degraders

Overexpression of the MYCN proto-oncogene is one of the strongest biomarkers for poor prognosis in neuroblastoma patients. N-Myc, encoded by MYCN, is a highly attractive yet “undruggable” target in neuroblastoma drug discovery. N-Myc is a short-lived protein in normal neuronal progenitor cells; however, in MYCN-amplified neuroblastoma cells, overexpressed N-Myc is stabilized by high levels of Aurora kinase A (Aurora-A). Several Aurora-A allosteric modulators have been developed to disassociate N-Myc binding and promote its degradation. These compounds function through a competitive mechanism against N-Myc, and clinical trial results suggest limited efficacy in high-risk neuroblastoma patients where N-Myc is highly expressed. To develop Aurora-A modulators with greater effects in destabilizing N-Myc, targeted degradation of Aurora-A was investigated in this study. First, we developed a highly selective Aurora-A-binding ligand by chemically modifying ribociclib, which targets CDK4/6. Next, a series of potent Aurora-A/N-Myc degraders were developed using proteolysis targeting chimaera (PROTAC) technology. Our lead compound, HLB-0532259, was found to substantially decrease N-Myc levels in neuroblastoma cells following the degradation of Aurora-A with nanomolar potency. Mechanistic studies suggest that HLB-0532259 binds to Aurora-A in an uncompetitive manner with respect to N-Myc, which contributes to its high potency for degrading the Aurora-A/N-Myc pool. Mass spectrometry analysis demonstrates that HLB-0532259 possesses remarkable proteome-wide selectivity for Aurora-A and N-Myc degradation. Further studies have revealed that HLB-0532259 exhibits nanomolar cytotoxicities against a panel of MYCN-amplified neuroblastoma cells, good pharmacokinetic properties, and favorable therapeutic outcomes in a xenograft neuroblastoma mouse model. Taken together, our data strongly support HLB-0532259 as a promising lead compound for neuroblastoma therapy.

Citation Format: Jian Tang, Ramkumar Moorthy, Ozlem Demir, Zachary D. Baker, Jordan A. Naumann, Katherine F. Jones, Michael J. Grillo, Ella Haefner, Ke Shi, Michaella J. Levy, Hideki Aihara, Reuben S. Harris, Rommie E. Amaro, Nicholas M. Levinson, Daniel A. Harki. Targeting N-Myc in neuroblastoma cells with selective Aurora kinase A degraders [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2135.

Cytidine acetylation yields a hypoinflammatory synthetic messenger RNA

Synthetic messenger RNA (mRNA) is an emerging therapeutic platform with important applications in oncology and infectious disease. Effective mRNA medicines must be translated by the ribosome but not trigger a strong nucleic acid-mediated immune response. To expand the medicinal chemistry toolbox for these agents, here we report the properties of the naturally occurring nucleobase N⁴-acetylcytidine (ac4C) in synthetic mRNAs. We find that ac4C is compatible with, but does not enhance, protein production in the context of synthetic mRNA reporters. However, replacement of cytidine with ac4C diminishes inflammatory gene expression in immune cells caused by synthetic mRNAs. Chemoproteomic capture indicates that ac4C alters the protein interactome of synthetic mRNAs, reducing binding to cytidine-binding proteins and an immune sensor. Overall, our studies illustrate the unique ability of ac4C to modulate RNA-protein interactions and provide a foundation for using N⁴-cytidine acylation to fine-tune the properties of nucleic acid therapeutics.

Dynamic RNA acetylation revealed by quantitative cross-evolutionary mapping

N4-acetylcytidine (ac4C) is an ancient and highly conserved RNA modification that is present on tRNA and rRNA and has recently been investigated in eukaryotic mRNA1-3. However, the distribution, dynamics and functions of cytidine acetylation have yet to be fully elucidated. Here we report ac4C-seq, a chemical genomic method for the transcriptome-wide quantitative mapping of ac4C at single-nucleotide resolution. In human and yeast mRNAs, ac4C sites are not detected but can be induced-at a conserved sequence motif-via the ectopic overexpression of eukaryotic acetyltransferase complexes. By contrast, cross-evolutionary profiling revealed unprecedented levels of ac4C across hundreds of residues in rRNA, tRNA, non-coding RNA and mRNA from hyperthermophilic archaea. Ac4C is markedly induced in response to increases in temperature, and acetyltransferase-deficient archaeal strains exhibit temperature-dependent growth defects. Visualization of wild-type and acetyltransferase-deficient archaeal ribosomes by cryo-electron microscopy provided structural insights into the temperature-dependent distribution of ac4C and its potential thermoadaptive role. Our studies quantitatively define the ac4C landscape, providing a technical and conceptual foundation for elucidating the role of this modification in biology and disease4-6.

Probing the Sensitivity of the Orbitrap Lumos Mass Spectrometer Using a Standard Reference Protein in a Complex Background

The use of mass spectrometry as a tool to detect proteins of biological interest has become a cornerstone of proteomics. The popularity of mass spectrometry-based methods has increased along with instrument improvements in detection and speed. The Orbitrap Fusion Lumos mass spectrometer has recently been shown to have better fragmentation and detection than its predecessors. Here, we determined the sensitivity of the Lumos using the NIST monoclonal antibody reference material at various concentrations to detect its peptides in a background of S. cerevisiae whole cell lysate, which was kept at a constant concentration. The data collected by data-dependent acquisition showed that the spiked protein could be detected at 10 pg by an average of 4 peptides in 250 ng of whole cell lysate when the instrument was operated by detecting the peptide masses in the Orbitrap and the fragment masses in the ion trap (FTIT mode). In contrast, when the peptides and fragments were both detected in the Orbitrap on either the Lumos or Q-Exactive Plus (FTFT mode), the lowest concentration of NIST monoclonal antibody detected was 50 pg. The Lumos can detect a single protein at a level 2500 times lower than the whole cell background and the combination of detecting ions in the Orbitrap and ion trap can improve the identification of low abundance proteins. Furthermore, the total number of proteins identified from decreasing starting amounts of whole cell extracts was determined. The Lumos, when operated in FTIT mode, was able to identify twice as many proteins compared to the Q-Exactive+ at 5 ng of whole cell lysate. Similar numbers of proteins were identified on both platforms at higher concentrations of starting material. Therefore, the Lumos mass spectrometer is especially useful for detecting proteins of low abundance in complex backgrounds or samples that have limited starting material.

SOCIETY FOR ENDOCRINOLOGY CLINICAL GUIDANCE: Inpatient management of cranial diabetes insipidus

Cranial diabetes insipidus (CDI) is a treatable chronic condition that can potentially develop into a life-threatening medical emergency. CDI is due to the relative or absolute lack of the posterior pituitary hormone vasopressin (AVP), also known as anti-diuretic hormone. AVP deficiency results in uncontrolled diuresis. Complete deficiency can lead to polyuria exceeding 10 L/24 h. Given a functioning thirst mechanism and free access to water, patients with CDI can normally maintain adequate fluid balance through increased drinking. Desmopressin (DDAVP, a synthetic AVP analogue) reduces uncontrolled water excretion in CDI and is commonly used in treatment. Critically, loss of thirst perception (through primary pathology or reduced consciousness) or limited access to water (through non-availability, disability or inter-current illness) in a patient with CDI can lead to life-threatening dehydration. This position can be further exacerbated through the omission of DDAVP. Recent data have highlighted serious adverse events (including deaths) in patients with CDI. These adverse outcomes and deaths have occurred through a combination of lack of knowledge and treatment failures by health professionals. Here, with our guideline, we recommend treatment pathways for patients with known CDI admitted to hospital. Following these guidelines is essential for the safe management of patients with CDI.

Marketplace Analysis of Conjugated Estrogens: Determining the Consistently Present Steroidal Content with LC-MS

Conjugated estrogens purified from pregnant mares urine has been used as estrogen hormone replacement therapy since 1942. Previously, methods were proposed to identify and quantify the components of this complex mixture but ultimately were withdrawn due to incomplete characterization of the product and difficulties in transferring the method between laboratories. The aim of the current study is to develop a LC method that can reliably detect multiple steroidal components in conjugated estrogen tablets and measure their relative amount. The method developed was optimized for UHPLC columns, and the elution profile was analyzed using high-resolution mass spectrometry. A total of 60 steroidal components were identified using their exact m/z, product ion spectra of known, and predicted conjugated estrogen structures. These components were consistently present in 23 lots of Premarin tablets spanning two production years. The ten conjugated estrogens identified in the USP monograph and other additional estrogens reported elsewhere are among the 60 steroidal components reported here. The LC-MS method was tested in different laboratories using multiple samples, and the obtained results were reproducible among laboratories.

Clinical characteristics of people experiencing biochemical hypoglycaemia during an oral glucose tolerance test: cross-sectional analyses from a UK multi-ethnic population

AIMS

People who experience biochemical hypoglycaemia during an oral glucose tolerance test (OGTT) may be insulin resistant, but this has not been investigated robustly, therefore we examined this in a population-based multi-ethnic UK study.

METHODS

Cross-sectional data from 6478 diabetes-free participants (849 with fasting insulin data available) who had an OGTT in the ADDITION-Leicester screening study (2005-2009) were analysed. People with biochemical hypoglycaemia (2-h glucose <3.3mmol/l) were compared with people with normal glucose tolerance (NGT) or impaired glucose regulation (IGR) using regression methods.

RESULTS

359 participants (5.5%) had biochemical hypoglycaemia, 1079 (16.7%) IGR and 5040 (77.8%) NGT. Biochemical hypoglycaemia was associated with younger age (P<0.01), white European ethnicity (P<0.001), higher HDL cholesterol (P<0.01), higher insulin sensitivity (P<0.05), and lower body mass index (P<0.001), blood pressure (P<0.01), fasting glucose (P<0.001), HbA1C (P<0.01), and triglycerides (P<0.01) compared with NGT and IGR separately in both unadjusted and adjusted (age, sex, ethnicity, body mass index, smoking status) models.

CONCLUSIONS

Biochemical hypoglycaemia during an OGTT in the absence of diabetes or IGR was not associated with insulin resistance, but instead appeared to be associated with more favourable glycaemic risk profiles than IGR and NGT. Thus, clinicians may not need to intervene due to biochemical hypoglycaemia on a 2-h OGTT.

Perinatal testosterone exposure and maternal care effects on the female rat's development and sexual behaviour

Natural variations in maternal care have profound influences on offspring behaviour, brain activity and hormone release. Measuring the amount of time that a rat dam spends licking/grooming (LG) her pups during their first week of life allows for characterisation of distinctive Low, Mid and High LG phenotypes. We have previously found that female offspring of High LG mothers are less sexually receptive, less motivated to mate and show a later onset of puberty relative to Low LG offspring. Given that High LG females are exposed to greater levels of testosterone in utero, we hypothesise that differences in sexual behaviour between High and Low LG female offspring are driven in part by differences in prenatal hormone exposure. To test this hypothesis, pregnant dams pre-characterised as Low, Mid, or High LG mothers were implanted with testosterone or placebo on gestational day (GD) 16. Offspring body weight and anogenital index were assessed at GD 21 and in adulthood. Age of vaginal opening and oestrous cyclicity were assessed to determine the timing of pubertal onset. Testosterone exposure removed the difference between LG phenotypes in pubertal onset by delaying vaginal opening and the appearance of first pro-oestrus. In adulthood, sexual behaviour in a paced mating chamber after sham surgery or ovariectomy with steroid-replacement was examined. Our findings show that Low, Mid and High LG female offspring are differentially affected by perinatal testosterone exposure, and that this exposure removes the precocial pubertal onset of Low LG offspring and increases the sexual proceptivity and receptivity of High LG offspring. These results suggest that maternal programming of the female reproductive system may be mediated, in part, through differences in perinatal testosterone exposure, instead of solely through maternal behaviour.

Analysis of Fluorescent Proteins with a Nanoparticle Probe

This letter presents the first application of high energy, single nanoparticle probes (e.g., 520 keV Au(400) 2nm NP) in the characterization of surfaces containing fluorescent proteins (e.g., GFP variants) by their co-emitted photon, electron and secondary ion signals. NP induced protein luminescence increases with the NP incident energy, is originated by the NP impact and is transferred to the protein fluorophor via electronic energy transfer. Multi-electron emission is observed per single NP impacts and their distributions are specific to the target morphology and composition. Fragment ions of protein sub-units consisting of 2-7 amino acid peptides are observed under individual NP impacts that can be correlated to the random protein orientation relative to the impact site (e.g., outer layer or "skin" of the protein).

The challenges with NOTES retroperitoneal access in humans

BACKGROUND

Animal studies have supported natural orifice transluminal endoscopic surgery (NOTES) retroperitoneal access. NOTES also may offer unique retroperitoneal access in humans.

OBJECTIVES

This study was designed to assess the feasibility of endoscopic transgastric and transrectal retroperitoneal access in a cadaver model using prone and supine positioning, and to compare NOTES retroperitoneal examination with endoscopic ultrasound.

METHODS

Using a multidisciplinary team, this institutional review board-approved study evaluated transgastric and transrectal retroperitoneal examination in six cadavers (3 male, 3 female; body mass index range, 25-37 kg/m(2)). Endoscopic ultrasound retroperitoneal examination preceded NOTES access. Transgastric Access: Using a prototype dual channel endoscope, a needle knife gastrotomy was created on the preantral posterior gastric wall. Retroperitoneal examination specifically targeted the pancreas and surrounding structures with the cadaver supine and prone. Transrectal Access: Using the same endoscope, a posterior needle knife rectotomy distal to the upper valve of Houston provided extraluminal access. Retroperitoneal examination proceeded with the cadaver prone and supine. Open dissection followed procedure completion.

RESULTS

Access into the retroperitoneum succeeded at all sites. Significant challenges locating identifiable landmarks were faced-mostly transrectal and improved transgastric prone. All cadavers, despite body mass index or sex, had significant retroperitoneal adipose tissue limiting the endoscopic view.

CONCLUSIONS

Although porcine studies have highlighted successful NOTES retroperitoneal procedures, the abundant human retroperitoneal adipose tissue challenged the translation of porcine research to humans. Additionally, although access to the retroperitoneal space and dissection within this space were accomplished easily, the appearance of cadaveric tissue and lack of blood flow made confident landmark identification impossible. Further study should continue in this area and focus on confident landmark identification for directed dissection. In a cadaveric model, this would best be improved by pre-NOTES anatomic marking or active perfusion of vasculature along with consideration of direct entry into the retroperitoneum from a targeted intraperitoneal site in clinical patients.

Endoscopic retrograde cholangiopancreatography using a single-balloon enteroscope in patients with altered Roux-en-Y anatomy

BACKGROUND AND STUDY AIMS

Endoscopic retrograde cholangiopancreatography (ERCP) is challenging to perform in patients with postsurgical gastrointestinal anatomy. We assessed the diagnostic and therapeutic success rates using single-balloon enteroscopy in patients with Roux-en-Y anastomosis.

PATIENTS AND METHODS

Patients who underwent single-balloon ERCP between April 2008 and February 2010 were retrospectively identified using a computerized endoscopy database. Diagnostic success was defined as successful duct cannulation or securing the diagnosis, and therapeutic success was defined as the ability to successfully carry out endoscopic therapy. Complications of ERCP were defined according to standard criteria.

RESULTS

A total of 50 patients (34-male, mean age 57 years, range 19 - 85 years) with Roux-en-Y anastomosis underwent ERCP using a single-balloon enteroscope on 56 occasions. Indications for ERCP were cholestasis, acute cholangitis, recurrent primary sclerosing cholangitis with strictures, and choledocholithiasis. Overall diagnostic success was achieved in 39 / 56 cases (70 %). Therapeutic success was achieved in 21/23 cases (91 %). In 16 cases therapeutic intervention was not required. Therapeutic interventions included balloon dilation of strictures (n = 14), retrieval of retained biliopancreatic stents (n = 5), biliary stone extraction (n = 2), insertion of biliopancreatic stents (n = 4), and biliary and pancreatic sphincterotomy (n = 5). No major complications occurred. Importantly, in 22 / 56 procedures (39 %) a prior attempt at ERCP failed using conventional colonoscopes; single-balloon ERCP was successful in 15 / 22 (68 %) of these cases.

CONCLUSIONS

Single-balloon ERCP is feasible in patients with complex postsurgical Roux-en-Y anastomosis, allows diagnostic evaluation and therapeutic intervention in patients with pancreaticobiliary disease, and is a useful salvage technique in the majority of patients in whom ERCP using colonoscopies has failed.

The role of endoscopic ultrasound for loco-regional staging of rectal cancer

Rectal cancer is projected to have the 10th highest incidence of cancer in the United States in 2009, with 40 870 estimated new cases this year. The prognosis for patients with rectal cancer is directly related to several factors, with the most important, based on current data, the extent of primary tumor invasion, the number of lymph nodes involved, involvement of the circumferential resection margin, and the presence of metastases. Contemporary therapy is dependent upon pre-surgical diagnostic imaging modalities, which influence the indication for neoadjuvant therapy and the decision process concerning the appropriate surgical approach. A comprehensive overview based on the currently available evidence of endoscopic ultrasound imaging in the loco-regional assessment of primary de novo rectal cancer evaluation following neoadjuvant therapy and post operative disease surveillance is presented. Relevant ano-rectal anatomy, staging systems for rectal cancer and alternative radiological staging strategies are also presented.

Endoscopic transpapillary gallbladder drainage: 10-year single center experience

AIM

A subset of patients with acute cholecystitis is severely ill and extremely high-risk to undergo cholecystectomy. Data on the use of endoscopic transpapillary gallbladder drainage (ETGBD) in the treatment of acute cholecystitis are limited. This article reviews the 10-year experience of ETGBD at Mayo Clinic and evaluated patient and procedure characteristics.

METHODS

A retrospective review of the endoscopy database from 1998-2007 was performed to identify patients who had undergone ETGBD. Clinical information and procedure details were abstracted from the electronic medical record.

RESULTS

Fifty one patients underwent ETGBD for acute cholecystitis between 1998 to July 2007. The mean age was 62+/-19 years and 67% of patients were males. The median number of comorbid medical conditions was two (range 0-5) and 27% had underlying diabetes mellitus. Acute calculous cholecystitis was the predominant indication for ETGBD (78%). A gallbladder stent was used in 33 (65%) patients, nasocholecystic drain in 14 (27%) patients, and both in four patients (8%). Bleeding (4%) and sedation-related complications (4%) were the most common complications noted. Among patients who underwent cholecystectomy, the majority (76%) needed an open procedure. The median time to cholecystectomy was 15 days (range 1-352 days). Four patients (8%) succumbed to septic shock during their hospitalization.

CONCLUSIONS

ETGBD is a valuable alternative therapeutic modality for the treatment of patients with acute cholecystitis who are at high-risk for early cholecystectomy, and/or those who have contraindications to percutaneous gallbladder drainage.

Endoscopic ultrasound (EUS) guided access and therapy of pancreatico-biliary disorders

Endoscopic ultrasound (EUS) has evolved from a purely diagnostic imaging modality to one that allows therapeutic intervention. It now serves as a viable alternative, and at times is preferred, to percutaneous and surgical techniques for obtaining biliary and pancreatic duct access and for providing drainage. EUS guided intervention is usually performed following failed endoscopic retrograde cholangiopancreatography (ERCP) or as an option for patients who decline surgical intervention or in poor operative candidates. Published data demonstrate overall technical success in 83% of patients with 12% experiencing a procedure related complication. New techniques and equipment must be developed to simplify and abbreviate the procedures, to limit complications, and improve outcomes. In addition, longitudinal data are needed to determine the long-term outcomes and role of EUS guided pancreaticobiliary intervention.

Pancreatic stent prophylaxis of post endoscopic retrograde cholangiopancreatography pancreatitis: spontaneous migration rates and clinical outcomes

AIM

Pancreatic duct (PD) stents diminish the risk of post endoscopic retrograde cholangiopancreatography (ERCP) pancreatitis (PEP) in high-risk patients; 3 Fr stents are reported to spontaneously migrate at a significantly higher rate than 5 Fr stents in a cohort of mostly sphincter of Oddi (SOD) patients. We sought to assess spontaneous migration rates of 5 Fr and 7 Fr stents and effectiveness in preventing PEP in a diverse group of high risk patients.

METHODS

A total of 4,332 ERCP exams performed between January 2002 and August 2005 were reviewed to identify patients undergoing PD stent placement. Follow-up was obtained from electronic medical records and contact with referring MDs. Plain abdominal radiographs were used to document stent passage.

RESULTS

PD stents for PEP prophylaxis were placed in 246 exams (232 patients) undergoing: PD (major or minor) sphincterotomy (84), ampullectomy (50), SOD (46), bile duct precut (35), papillary stenosis balloon dilation (9) and difficult cannulation (8). Stents placed: 218 5-Fr (140 were 3 cm long and 78 =or> 5 cm long) and 28 7-Fr (12 were 3 cm long, 16=or> 5cm long). Follow-up was available in 197 (171 5-Fr, 26 7-Fr) of 246 placements (80%). Twenty of 171 5-Fr stents were electively removed via EGD within=or< 24 h per endoscopist preference and were not included in analysis; 128 of the remaining 151 5-Fr stents (85%) spontaneously migrated by (or within) median of 8 days and 23 failed to pass and required EGD removal. Of 26 7-Fr stents one was electively removed =or< 24 h later; of the remaining 25, 15 (60%) spontaneously migrated by median of 16 days, 10 required EGD removal. The spontaneous migration rate of 5 Fr stents was: 1) significantly higher than 7 Fr stents; 2) significantly higher than the previously reported 67% passage rate of 5 Fr stents; and 3) similar to the previously reported 86% passage rate of 3 Fr stents. PEP occurred in 15% (n=36: 24 mild, 11 moderate, 1 severe).

CONCLUSION

The spontaneous dislodgement rate of 5 Fr stents in patients where the indication is primarily non-SOD is approximately 85% - significantly higher than previously reported and similar to the reported rate of spontaneous dislodgement of 3 Fr stents in SOD patients; 5 Fr stents migrate spontaneously earlier and more frequently than 7 Fr stents.

Frequency of visualization of presumed celiac ganglia by endoscopic ultrasound

BACKGROUND AND STUDY AIMS

Celiac ganglia can be visualized by endoscopic ultrasound (EUS). It is unknown how often ganglia are visualized during EUS, and what clinical factors are associated with ganglion visualization. The aim of this study was to prospectively evaluate the frequency of visualization of presumed celiac ganglia by EUS and to identify factors that predict their visualization.

PATIENTS AND METHODS

Clinical, demographic, EUS, and cytologic data were collected prospectively from 200 unselected patients who were undergoing EUS in a tertiary referral centre. When presumed celiac ganglia were visualized, their size, number, location, and echo features were noted. When presumed ganglia were aspirated, the results of cytology were recorded.

RESULTS

The most common indication for EUS was investigation of a pancreatic mass or cyst (25 %). Presumed celiac ganglia were identified in 81 % of patients overall. Logistic regression analysis determined that female sex and having no prior history of gastrointestinal surgery were independently associated with ganglion visualization. Among patients whose ganglia were visualized, more ganglia were seen per patient with linear echo endoscopes (2, range 0 - 5) than with radial echo endoscopes (1, range 0 - 4) ( P = 0.001). Presumed celiac ganglia were aspirated in 10 patients; and cytologic examination revealed neural ganglia in all of these.

CONCLUSIONS

Celiac ganglia can be visualized by EUS in most patients who undergo upper gastrointestinal EUS examinations, and are best seen with linear-array echo endoscopes. Ganglia can usually be differentiated from lymph nodes on the basis of their endosonographic appearance.

Endoscopic retrograde cholangiopancreatography in post-Whipple patients

BACKGROUND AND STUDY AIMS

Endoscopic retrograde cholangiopancreatography (ERCP) is an established modality for evaluation and treatment of pancreaticobiliary disorders. However, it is technically more challenging in patients with post-surgical anatomy. The success rate of ERCP in patients with prior pancreaticoduodenectomy (Whipple resection) is unknown. We assessed the technical success and safety of ERCP in this patient population.

PATIENTS AND METHODS

Post pancreaticoduodenectomy patients who had undergone ERCP between January 2002 and May 2005 were identified through a computerized medical index system. ERCP was considered successful if the duct of clinical interest had been cannulated and endoscopic therapy had been performed when indicated.

RESULTS

ERCP was attempted 88 times in 51 patients with prior pancreaticoduodenectomy, including 37 procedures for pancreatic indications, 44 for biliary obstruction, and 7 for both biliary and pancreatic indications. The overall technical success rate of ERCP based on the intention behind the procedure was 51 % (45 of the 88 procedures). Success was significantly more likely for biliary indications (37/44, 84 %) than for pancreatic indications (3/37, 8 %) ( P < or = .001). Complications occurred in 2 % of the procedures and included one self- contained perforation treated medically and one Mallory-Weiss tear.

CONCLUSIONS

When performed by experienced endoscopists, ERCP in patients with prior pancreaticoduodenectomy is safe, with a high success rate for biliary indications and a low success rate for pancreatic duct indications. Better methods of achieving pancreatic duct cannulation after pancreaticoduodenectomy are needed.

Endoscopic retrograde cholangiopancreatography catheter and accessory exchange using a short hydrophilic guide wire: a prospective study

BACKGROUND AND STUDY AIMS

Although hydrophilic guide wires can be used to facilitate stricture cannulation during endoscopic retrograde cholangiopancreatography (ERCP), some endoscopists avoid using them because of concerns about wire loss during exchange. There are no data available on the outcomes of using a short hydrophilic guide wire during ERCP. The aim of this study was to assess the outcomes of therapeutic ERCP procedures in which a short, completely hydrophilic guide wire was used exclusively.

PATIENTS AND METHODS

A total of 100 patients undergoing ERCP were studied prospectively. A 0.035-inch, 260-cm long, angled-tip hydrophilic wire (Terumo Glidewire) was used initially. Hydraulic catheter exchange was performed as follows: during catheter withdrawal the assistant advanced all the available wire into the catheter; a 12-ml syringe was then attached to the catheter and water was flushed under pressure to "float the wire" and maintain its position during catheter removal. Variables evaluated included exchange times and wire loss rates.

RESULTS

A total of 223 catheter exchanges were performed, 132 (59%) using the Olympus V-Scope (which held the wire in 62% of cases): 15% of exchanges were with catheters/accessories designed for short-wire use (Boston Scientific Rapid Exchange Biliary System or Rx System), and 85% were with a variety of standard-length accessories. Overall, the mean exchange time was 26 seconds (range 6 - 90 seconds, standard deviation 12 seconds). The mean exchange time was faster with the V-Scope and with non-Rx-System accessories. Wire loss occurred in 5 % of all exchanges. Desired ductal/stricture access was achieved in all the patients.

CONCLUSIONS

Exchange of short hydrophilic wires is quick and reliable. The Olympus V-Scope is able to hold the wire in some cases. Monorail-type devices and accessories slow catheter exchange down slightly because hydraulic exchange cannot be performed using these systems.

The relationship between neuropeptide Y expression and headache in pituitary tumours

Patients with pituitary tumours often present with disabling headache but there is no clear relationship between tumour size and headache. Neuropeptide Y (NPY) has been identified in pituitary tumours and may serve as a biochemical marker of the propensity for headache. Using immunohistochemical techniques we examined 27 consecutive pituitary adenoma specimens for NPY (including one normal postmortem control anterior pituitary specimen). A separate observer divided the patients into two groups: headache and non-headache. The association between the presence of NPY and headache was tested. NPY positive immunoreactivity was seen in 13 tumour specimens (50%, 13 of 26 pituitary tumour specimens), characterized by cytoplasmic and nuclear staining patterns. There was no significant association between the presence of NPY and headache (chi(2) = 0.9, P = 0.34). We did not observe NPY in the normal anterior pituitary control specimen. NPY was present in four of five (80%) growth hormone-secreting tumours and two of two (100%) prolactinomas, compared with four of 11 (36%) non-functioning adenomas. The mechanism of many pituitary tumour-associated headaches remains undetermined. The significance of NPY positivity in pituitary tumours is unknown, although the results of this study may implicate this peptide in the control of somatotroph and lactotroph activity. Our data do not support a clear role for NPY pituitary tumour-associated headache.

Inhibition of nociceptive dural input in the trigeminal nucleus caudalis by somatostatin receptor blockade in the posterior hypothalamus

Somatostatin is a neuromodulator in the central nervous system and is involved in the regulation of metabolic and neuroendocrine functions. Recent experimental and clinical findings point to a role for somatostatin in the central processing of nociception. We studied the effects of somatostatin receptor modulation in the posterior hypothalamic area (PH) of the rat on dural nociceptive input. Somatostatin (10 microg/microl) and the somatostatin antagonist cyclo-somatostatin (50 microg/microl) were microinjected into the PH and the effects on responses of neurons in the trigeminal subnucleus caudalis studied. Injection of somatostatin (n=11) did not affect A- and C-fibre responses to dural electrical stimulation, nor was spontaneous activity altered (P>0.05). Injection of cyclo-somatostatin (n=10) into the PH reduced A-(-35.5+/-5.8%) and C-fibre (-43.1+/-7.5%) responses to dural stimulation and resulted in decreased spontaneous activity (-38.1+/-7.3%, P<0.05). Responses to facial thermal stimulation were decreased by 51.2+/-5.8% (n=5). Control injections had no significant effect (n=9). Blockade of somatostatin receptors in the PH has an anti-nociceptive effect on dural and facial input, probably mediated via GABAergic mechanisms. As somatostatin is also involved in hypothalamic regulation of metabolic, neuroendocrine and autonomic functions, somatostatin receptor mechanisms in the PH may play a role in the pathophysiology of primary headache disorders, such as migraine or cluster headache.

The clinical characteristics of headache in patients with pituitary tumours

The clinical characteristics of 84 patients with pituitary tumour who had troublesome headache were investigated. The patients presented with chronic (46%) and episodic (30%) migraine, short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT; 5%), cluster headache (4%), hemicrania continua (1%) and primary stabbing headache (27%). It was not possible to classify the headache according to International Headache Society diagnostic criteria in six cases (7%). Cavernous sinus invasion was present in the minority of presentations (21%), but was present in two of three patients with cluster headache. SUNCT-like headache was only seen in patients with acromegaly and prolactinoma. Hypophysectomy improved headache in 49% and exacerbated headache in 15% of cases. Somatostatin analogues improved acromegaly-associated headache in 64% of cases, although rebound headache was described in three patients. Dopamine agonists improved headache in 25% and exacerbated headache in 21% of cases. In certain cases, severe exacerbations in headache were observed with dopamine agonists. Headache appears to be a significant problem in pituitary disease and is associated with a range of headache phenotypes. The presenting phenotype is likely to be governed by a combination of factors, including tumour activity, relationship to the cavernous sinus and patient predisposition to headache. A proposed modification of the current classification of pituitary-associated headache is given.

No relationship between vasoactive intestinal polypeptide expression and headache in pituitary tumours

BACKGROUND

Clinical studies have noted the common presentation of pituitary tumours with significant headache. This has been considered to be one, or a combination of, increased cranial pressure, tumour size with dural stretch, or cavernous sinus invasion. Newer hypotheses suggest an association between the presence of pituitary tumour-associated headaches and the expression and release of nociceptive substances. Vasoactive intestinal polypeptide (VIP), a marker of the cranial parasympathetic system, is increased during acute attacks of some primary headaches, and with its expression in the pituitary may link some pituitary tumours to their headache presentations.

METHODS

Using immunohistochemical techniques, VIP expression in pituitary tumour specimens was examined to determine if there was a relationship between the presence or absence of pituitary-associated headache and the expression of VIP immunoreactivity (VIP-IR). A qualitative analysis of the VIP-IR in pituitary cells was performed by observers blinded to the headache status of each patient. The presence of VIP-IR and headache were treated as binary variables and associations tested with chi-square tests.

RESULTS

Forty-five per cent of specimens positive for VIP were from patients presenting with headache. There was no statistically significant association between the presence of VIP-IR and headache (chi(2) = 0.077, P = 0.781).

CONCLUSION

Although the significance of VIP positivity in pituitary tumour-associated headache is unknown it seems unrelated to headache. It remains possible that the mechanism of these headaches relates to the production of either an as yet unidentified peptide, or a combination of nociceptive peptides.

Octreotide is not effective in the acute treatment of migraine

The aim of this study was to determine whether subcutaneous octreotide is effective for the treatment of acute migraine. Patients with migraine with and without aura as classified by the International Headache Society were recruited to a double-blind placebo-controlled crossover study. Patients were instructed to treat two attacks of at least moderate pain severity, with at least a 7 day interval, using subcutaneous 100 microg octreotide or matching placebo. The primary endpoint was the headache response defined as: severe or moderate pain becomes mild or nil, at 2 h. The primary endpoint was analysed using a Multilevel Analysis approach. Secondary end-points included associated symptoms and a four-point functional disability score. The study was powered to detect a 30% difference at an alpha of 0.05 and a beta of 0.8. A total of 51 patients were recruited, of whom 42 provided efficacy data on an attack treated with octreotide and 41 with placebo. Modelling the headache response as a binomial determined by treatment, using the patient as the level 2 variable, and considering a possible period effect, and sex and migraine type as other variables of interest, subcutaneous octreotide was not significantly superior to placebo. The two hour headache response rates were 20% for placebo and 14% for octreotide, whilst the two hour pain free rates were 7% and 2%, respectively. Subcutaneous octreotide 100 microg is not effective in the acute treatment of migraine when compared to placebo.

Differential modulation of nociceptive dural input to [hypocretin] orexin A and B receptor activation in the posterior hypothalamic area

The novel neuropeptides orexin A and B are selectively synthesised in the lateral and posterior hypothalamus and are involved in hypothalamic regulation of autonomic and neuroendocrine functions. Recent findings point also to a role in nociception. As the posterior hypothalamus is involved in the central modulation of nociception we studied the effects of hypocretin/orexin receptor activation in the posterior hypothalamic area (PH) of the rat on dural nociceptive input. Orexins were microinjected into the PH and the effects on responses of neurones in the caudal trigeminal nucleus studied. Injection of orexin A decreased the A- and C-fibre responses to dural electrical stimulation as well as spontaneous activity. Responses to noxious thermal stimulation of the facial skin were also decreased by orexin A. Injection of orexin B into the PH, however, elicited increased responses to dural stimulation in A- and C-fibre responses and resulted in increased spontaneous activity. Responses to facial thermal stimulation were also increased by orexin B. Control injection of saline into the PH had no significant effect. The results show a differential modulation of dural nociceptive input by orexin A and B receptor activation in the PH. The results support the role of the PH in the nociceptive processing of meningeal input. As both peptides are also involved in hypothalamic regulation of neuroendocrine and autonomic functions, orexinergic mechanisms in the PH may provide a link for endocrine and autonomic changes as well as nociceptive phenomena seen in primary headache disorders.

The association between calcitonin gene-related peptide (CGRP), substance P and headache in pituitary tumours

OBJECTIVES

To determine if the differential expression of calcitonin gene-related peptide (CGRP) or substance P (SP) in a range of pituitary tumours was related to the presence or absence of headache.

METHODS

Using recognised immunohistochemical techniques we examined twenty-six consecutive pituitary adenoma specimens for the presence of CGRP and SP. We included one normal post mortem pituitary specimen for comparison. A separate observer divided the patients into two groups: headache and non-headache. The association between the presence of CGRP, SP and headache was observed.

RESULTS

We observed CGRP in seven specimens (27%) and SP in six tumour specimens (23%), with cytoplasmic staining being the predominant morphological picture. CGRP and SP were co-expressed in the same tumour specimen in five cases. There was no significant association between the presence of CGRP and headache (chi(2) 0.86; P = 0.35). We did not observe CGRP or SP in the control specimen. There was no correlation between tumour subtype and the presence of CGRP or SP.

CONCLUSIONS

The mechanism of pituitary tumour-associated headache remains undetermined. The significance of the presence of CGRP and SP in pituitary tumours is unknown but does not appear to be related to headache or endocrine activity of the tumour.

SUNCT syndrome secondary to prolactinoma

Short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT) syndrome is a rare form of primary headache disorder, although secondary causes, particularly posterior fossa abnormalities, are well known. We report a case of SUNCT syndrome secondary to a prolactinoma. Administration of dopamine agonists led to complete resolution of the SUNCT attacks. This case, together with other similar case reports in the literature, highlight the importance of excluding a diagnosis of pituitary adenoma in all suspected cases of SUNCT syndrome, especially as the headache can precede more classical pituitary symptoms by a considerable period of time. Clinicians managing patients with suspected SUNCT syndrome should elicit a history of symptoms associated with pituitary neoplasms, perform a magnetic resonance imaging scan of the brain and pituitary, and screen for serum hormonal abnormalities.

Effect of IL-1β microinjection into the posterior hypothalamic area on trigeminal nociception in the rat

The hypothalamus has been implicated in the pathophysiology of the most disabling forms of primary headache, namely migraine and cluster headache. Interleukin-1beta (IL-1beta) is highly expressed in the hypothalamus. We recorded from the trigeminal nucleus caudalis of rats using extracellular electrophysiological methods from neurons responding to electrical stimulation of the peri-middle meningeal artery dura mater and having receptive fields in the ophthalmic division of the trigeminal nerve. Data were collected from fifteen clusters of wide-dynamic range neurons with stable baseline firing responses between 97 and 101% ( n=3 for each unit) to stimulation. Microinjection of IL-1beta into the posterior hypothalamus of 9 animals resulted in a modest inhibition of evoked trigeminal responses in three units, no effect in six and no overall effect for the entire cohort studied. The mean maximum response was a non-significant reduction in firing to 83+/-7% ( n=9) at 30 minutes post-injection of IL-1beta. There was some variation of effect dependent on site of injection with central posterior hypothalamus being the predominant area that resulted in inhibition. There was no inhibition in the six animals injected with vehicle (saline). If there is an important effect for IL-1beta in the posterior hypothalamus it is likely to be highly somatotopically restricted.

Prolactinomas, dopamine agonists and headache: two case reports

Headache is a common problem in patients with pituitary tumours. Small pituitary lesions can cause debilitating headache, suggesting that the size of the pituitary tumour may not be the only causal factor in pituitary-related headache. We present two cases of prolactinoma-associated headache. The first case has a clinical diagnosis of short-lasting unilateral headache attacks with conjunctival injection and tearing (SUNCT). The second case has a clinical diagnosis of hemicrania continua and idiopathic stabbing headache. In each case, the administration of dopamine agonists has led to an exacerbation of symptoms. We review the relevant literature to understand the pathophysiological implications of these cases.

Endoscopic removal of a biliary Wallstent with a suture-cutting device in a patient with primary pancreatic lymphoma

This report describes the case of a 74-year-old woman who had previously had a metal stent placed to relieve jaundice resulting from a pancreatic head tumor, suspected to be adenocarcinoma. The tumor was subsequently found to be a non-Hodgkin's large-cell lymphoma, which had shown a rapid response to chemotherapy without tumor recurrence in over 3 years since the diagnosis. She was referred for management of recurrent jaundice and cholangitis resulting from repeated metal stent occlusion, despite multiple endoscopic procedures and failed surgical removal. This report describes experience with the use of an endoscopic suture-cutting device to assist in the removal of the metal stent. It also highlights the need for proper patient selection before placement of biliary metal stents.