Commercial Immunoglobulin Products Contain Neutralizing Antibodies Against Severe Acute Respiratory Syndrome Coronavirus 2 Spike Protein

BACKGROUND

Patients with antibody deficiency respond poorly to coronavirus disease 2019 (COVID-19) vaccination and are at risk of severe or prolonged infection. They are given long-term immunoglobulin replacement therapy (IRT) prepared from healthy donor plasma to confer passive immunity against infection. Following widespread COVID-19 vaccination alongside natural exposure, we hypothesized that immunoglobulin preparations will now contain neutralizing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike antibodies, which confer protection against COVID-19 disease and may help to treat chronic infection.

METHODS

We evaluated anti-SARS-CoV-2 spike antibody in a cohort of patients before and after immunoglobulin infusion. Neutralizing capacity of patient samples and immunoglobulin products was assessed using in vitro pseudovirus and live-virus neutralization assays, the latter investigating multiple batches against current circulating Omicron variants. We describe the clinical course of 9 patients started on IRT during treatment of COVID-19.

RESULTS

In 35 individuals with antibody deficiency established on IRT, median anti-spike antibody titer increased from 2123 to 10 600 U/mL postinfusion, with corresponding increase in pseudovirus neutralization titers to levels comparable to healthy donors. Testing immunoglobulin products directly in the live-virus assay confirmed neutralization, including of BQ1.1 and XBB variants, but with variation between immunoglobulin products and batches.Initiation of IRT alongside remdesivir in patients with antibody deficiency and prolonged COVID-19 infection (median 189 days, maximum >900 days with an ancestral viral strain) resulted in clearance of SARS-CoV-2 at a median of 20 days.

CONCLUSIONS

Immunoglobulin preparations now contain neutralizing anti-SARS-CoV-2 antibodies that are transmitted to patients and help to treat COVID-19 in individuals with failure of humoral immunity.

Immunoglobulin Replacement Therapy During COVID-19 Pandemic: Practical and Psychological Impact in Patients with Antibody Deficiency

PURPOSE

The COVID-19 pandemic has impacted on how health services deliver care and the mental health of the population. Due to their clinical vulnerability, to reduce in-hospital attendances during the COVID-19 pandemic, modifications in immunoglobulin treatment regimens were made for patients with antibody deficiency. These patients were also likely to experience social isolation due to shielding measure that were advised. We aimed to investigate the impact of modifying immunoglobulin treatment regimen on infection and mental health burden during shielding restrictions.

METHOD

Patients on immunoglobulin replacement therapy (IGRT) responded to a standardised questionnaire examining self-reported infection frequency, anxiety (GAD-7), depression (PHQ-8), fatigue (FACIT), and quality of life during the pandemic. Infection frequency and immunoglobulin trough levels were compared to pre-pandemic levels.

RESULTS

Patients who did not change treatment modality or those who received immunoglobulin replacement at home during the pandemic reported fewer infections. In patients who received less frequent hospital infusions, there was no significant increase in infections whilst immunoglobulin trough levels remained stable. There was no significant difference in anxiety, or depression scores between the treatment modality groups. Patients reported higher fatigue scores compared to the pre-COVID general population and in those discharged following hospitalisation for COVID.

CONCLUSION

Changing immunoglobulin treatment regimen did not negatively impact infection rates or psychological wellbeing. However, psychological welfare should be prioritised for this group particularly given uncertainties around COVID-19 vaccination responsiveness and continued social isolation for many.

Activation of the cGAS-STING innate immune response in cells with deficient mitochondrial topoisomerase TOP1MT

The recognition that cytosolic mitochondrial DNA (mtDNA) activates cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS-STING) innate immune signaling has unlocked novel disease mechanisms. Here, an uncharacterized variant predicted to affect TOP1MT function, P193L, was discovered in a family with multiple early onset autoimmune diseases, including Systemic Lupus Erythematosus (SLE). Although there was no previous genetic association between TOP1MT and autoimmune disease, the role of TOP1MT as a regulator of mtDNA led us to investigate whether TOP1MT could mediate the release of mtDNA to the cytosol, where it could then activate the cGAS-STING innate immune pathway known to be activated in SLE and other autoimmune diseases. Through analysis of cells with reduced TOP1MT expression, we show that loss of TOP1MT results in release of mtDNA to the cytosol, which activates the cGAS-STING pathway. We also characterized the P193L variant for its ability to rescue several TOP1MT functions when expressed in TOP1MT knockout cells. We show that the P193L variant is not fully functional, as its re-expression at high levels was unable to rescue mitochondrial respiration deficits, and only showed partial rescue for other functions, including repletion of mtDNA replication following depletion, nucleoid size, steady state mtDNA transcripts levels and mitochondrial morphology. Additionally, expression of P193L at endogenous levels was unable to rescue mtDNA release-mediated cGAS-STING signaling. Overall, we report a link between TOP1MT and mtDNA release leading to cGAS-STING activation. Moreover, we show that the P193L variant has partial loss of function that may contribute to autoimmune disease susceptibility via cGAS-STING mediated activation of the innate immune system.

Functional characterization of two variants of mitochondrial topoisomerase TOP1MT that impact regulation of the mitochondrial genome

TOP1MT encodes a mitochondrial topoisomerase that is important for mtDNA regulation and is involved in mitochondrial replication, transcription, and translation. Two variants predicted to affect TOP1MT function (V1 - R198C and V2 - V338L) were identified by exome sequencing of a newborn with hypertrophic cardiomyopathy. As no pathogenic TOP1MT variants had been confirmed previously, we characterized these variants for their ability to rescue several TOP1MT functions in KO cells. Consistent with these TOP1MT variants contributing to the patient phenotype, our comprehensive characterization suggests that both variants had impaired activity. Critically, we determined neither variant was able to restore steady state levels of mitochondrial-encoded proteins nor to rescue oxidative phosphorylation when re-expressed in TOP1MT KO cells. However, we found the two variants behaved differently in some respects; while the V1 variant was more efficient in restoring transcript levels, the V2 variant showed better rescue of mtDNA copy number and replication. These findings suggest that the different TOP1MT variants affect distinct TOP1MT functions. Altogether, these findings begin to provide insight into the many roles that TOP1MT plays in the maintenance and expression of the mitochondrial genome and how impairments in this important protein may lead to human pathology.

Bowel Histology of CVID Patients Reveals Distinct Patterns of Mucosal Inflammation

Diarrhea is the commonest gastrointestinal symptom in patients with common variable immunodeficiency (CVID). Different pathologies in patients' bowel biopsies have been described and links with infections have been demonstrated. The aim of this study was to analyze the bowel histology of CVID patients in the Royal-Free-Hospital (RFH) London CVID cohort. Ninety-five bowel histology samples from 44 adult CVID patients were reviewed and grouped by histological patterns. Reasons for endoscopy and possible causative infections were recorded. Lymphocyte phenotyping results were compared between patients with different histological features. There was no distinctive feature that occurred in most diarrhea patients. Out of 44 patients (95 biopsies), 38 lacked plasma cells. In 14 of 21 patients with nodular lymphoid hyperplasia (NLH), this was the only visible pathology. In two patients, an infection with Giardia lamblia was associated with NLH. An IBD-like picture was seen in two patients. A coeliac-like picture was found in six patients, four of these had norovirus. NLH as well as inflammation often occurred as single features. There was no difference in blood lymphocyte phenotyping results comparing groups of histological features. We suggest that bowel histology in CVID patients with abdominal symptoms falls into three major histological patterns: (i) a coeliac-like histology, (ii) IBD-like changes, and (iii) NLH. Most patients, but remarkably not all, lacked plasma cells. CVID patients with diarrhea may have an altered bowel histology due to poorly understood and likely diverse immune-mediated mechanisms, occasionally driven by infections.

A rare and unusual complication of the STING procedure

An 8-year-old boy underwent a STING procedure for vesicoureteric reflux. 11 years later, at 19-years-old he presented with the passage of sediment per urethra every 7 weeks. CT scan demonstrated a lesion at the right VUJ. Cystoscopy revealed a 2cm suburothelial mass adjacent to the VUJ, with normal urothelium overlying it. Resection of the area revealed a white plastic-like substance, consistent with the bulking agent Deflux, which was scraped away. The patient made an uneventful recovery and at review, 3 months later, is symptom free. Our case demonstrates a rare and unusual complication of the STING procedure.

Section headings

Endourology, General Urology, Paediatrics.

Altered Microbiota, Impaired Quality of Life, Malabsorption, Infection, and Inflammation in CVID Patients With Diarrhoea

Background: Diarrhoea is the commonest gastrointestinal symptom in patients with common variable immunodeficiency (CVID). Objective: The aim of this study was to describe the prevalence and clinical presentation of chronic and recurrent diarrhoea in the Royal-Free-Hospital (RFH) London CVID cohort, including symptoms, infections, level of inflammation, and microbial diversity. Methods: A cross-sectional study of adult CVID patients (139 out of 172 diagnosed with CVID completed the screening questionnaire). Those with diarrhoea ≥6 days/month had stool and blood samples analysed and completed the short Inflammatory Bowel Disease Questionnaire (sIBDQ). BMI, spleen-size, lymphocytes and gut-microbial diversity were compared. Due to logistical and clinical restraints, not all patients could be analysed on all measures. Results: 46/139 (33.1%) patients had current significant diarrhoea. In patients with past or present diarrhoea, BMI was lower (median 23.7 vs. 26, p = 0.005), malabsorption more common (57.97 vs. 35.71%, p = 0.011). CD4+ lymphocytes were higher in patients with diarrhoea (p = 0.028; n = 138), but CD4+ naïve lymphocytes were significantly higher in non-diarrhoea patients (p = 0.009, N = 28). Nine patients had confirmed or probable current gastrointestinal infections. Calprotectin was >60 μg/g in 13/29 with significant diarrhoea including 9 without infection. SIBDQ revealed a low median score of 4.74. Microbial alpha diversity was significantly lower in CVID patients compared to healthy household controls. There was no significant difference in alpha diversity in relation to antibiotic intake during the 6 weeks prior to providing samples. Conclusion: Patients with CVID and significant diarrhoea had infections, raised calprotectin, malabsorption, a lower BMI, an impaired quality of life (comparable to active IBD), and they differed from non-diarrhoea patients in their lymphocyte phenotyping. Furthermore, microbial diversity was altered. These findings strongly imply that there may be an inflammatory nature and a systemic predisposition to diarrhoea in CVID, which necessitates further investigation.

Successful outcome following allogeneic hematopoietic stem cell transplantation in adults with primary immunodeficiency

The primary immunodeficiencies (PIDs), rare inherited diseases characterized by severe dysfunction of immunity, have been successfully treated by allogeneic hematopoietic stem cell transplantation (Allo-HSCT) in childhood. Controversy exists regarding optimal timing and use of Allo-HSCT in adults, due to lack of experience and previous poor outcomes. Twenty-nine consecutive adult patients, with a mean age at transplant of 24 years (range, 17-50 years), underwent Allo-HSCT. Reduced-intensity conditioning (RIC) included fludarabine (Flu)/melphalan/alemtuzumab (n = 20), Flu/busulfan (Bu)/alemtuzumab (n = 8), and Flu/Bu/antithymocyte globulin (n = 1). Stem cell donors were matched unrelated donors or mismatched unrelated donors (n = 18) and matched related donors (n = 11). Overall survival (OS), event-free survival, transplant-related mortality (TRM), acute and chronic graft-versus-host disease incidence and severity, time to engraftment, lineage-specific chimerism, immune reconstitution, and discontinuation of immunoglobulin replacement therapy were recorded. OS at 3 years for the whole cohort was 85.2%. The rarer PID patients without chronic granulomatous disease (CGD) achieved an OS at 3 years of 88.9% (n = 18), compared with 81.8% for CGD patients (n = 11). TRM was low with only 4 deaths observed at a median follow-up of 3.5 years. There were no cases of early or late rejection. In all surviving patients, either stable mixed chimerism or full donor chimerism were observed. At last follow-up, 87% of the surviving patients had no evidence of persistent or recurrent infections. Allo-HSCT is safe and effective in young adult patients with severe PID and should be considered the treatment of choice where an appropriate donor is available.

Virtual stone clinic – the future of stone management?

Objectives:

Increasing demands on the urology outpatient department at Brighton and Sussex University Hospitals (BSUH) have posed a significant challenge on the provision of a timely service for patients with stone disease. This study aimed to evaluate the patient outcomes and waiting times achieved with a newly implemented virtual stone clinic (VSC).

Materials and methods:

All new stone referrals received between August 2016 to January 2017 at BSUH were discussed in the VSC. Patients were reviewed within seven days of referral by a multidisciplinary team led by a consultant stone surgeon. A prospectively collected database was generated with primary outcomes including discharge to primary care, need for further diagnostics, re-review at VSC, direct booking for treatment and referral to a traditional outpatient stone clinic. Waiting times between the VSC and previously used outpatient stone clinic were also compared.

Results:

A total of 526 cases were reviewed in the VSC. One-quarter of patients were discharged following initial VSC review with a further two-thirds discharged after re-review. Treatment was offered to 101 patients, primarily in the form of lithotripsy (65%). Eighty-six patients required formal outpatient clinic appointments. Waiting lists for stone appointments were cleared within two months of implementation of the VSC. Outcomes were very favourable, with only three patients requiring emergency admission for management of their stone disease.

Conclusion:

The VSC model provides a clinically and cost-effective method of managing patients with urinary tract stones with significantly reduced waiting times and overall improved patient satisfaction. Level of evidence: Not applicable for this multicentre audit.

Transmission of Hepatitis B Core Antibody and Galactomannan Enzyme Immunoassay Positivity via Immunoglobulin Products: A Comprehensive Analysis

BACKGROUND

Therapeutic immunoglobulins are used as replacement or immunomodulatory therapy, but can transmit clinically important molecules. We investigated hepatitis B virus (HBV) antibodies and galactomannan enzyme immunoassay (GM-EIA) positivity. Detection of HBV core antibody may prompt antiviral prophylaxis when commencing therapy such as rituximab; a positive GM-EIA result prompts investigation or treatment for invasive fungal disease.

METHODS

We performed a cross-sectional analysis of HBV serology in 80 patients established (>6 months) on immunoglobulin therapy; prospective analysis of HBV serology in 16 patients commencing intravenous immunoglobulin (IVIG); and pre- and post-infusion analysis of GM-EIA in 37 patients receiving IVIG.

RESULTS

Pre-IVIG, 9 of 80 patients tested positive for HBV surface antibody and 1 of 80 tested equivocal for HBV core antibody. On IVIG, 79 of 79 tested positive for surface antibody, 37 of 80 tested positive for core antibody, and 10 of 80 tested equivocal for core antibody. There were significant differences by product, but among patients receiving products that appear to transmit core antibody, negative results correlated with lower surface antibody titers and longer time since infusion, suggesting a simple concentration effect. There was a progressive increase with each infusion in the percentage of patients testing positive for HBV core antibody among patients newly commencing IVIG. Some patients "seroreverted" to negative during therapy. Certain IVIG products tested positive for GM-EIA and there were rises in index values in corresponding patient samples from pre- to post-infusion. Overall, 5 of 37 patient samples pre-infusion and 15 of 37 samples post-infusion tested positive for GM-EIA.

CONCLUSIONS

HBV antibodies and GM-EIA positivity are common in patients receiving IVIG and confound diagnostic results.

'A reservoir within a reservoir' - An unusual complication associated with a defunctioned inflatable penile prosthesis reservoir

INTRODUCTION

Inflatable penile prostheses (IPP) have been a successful method of treating men with erectile dysfunction since the early 1970s. IPP are comprised of two intracorporal cylinders, a scrotal pump and a fluid reservoir.

PRESENTATION OF CASE

We present a case of a retained reservoir in a sixty eight year old gentlemen presenting with a cystic abdominal mass and bothersome LUTS, 15 years after the removal of the penile components of a three-piece penile prosthesis. Percutaneous drainage of the cyst was performed, with four litres of purulent fluid evacuated. A midline laparotomy was required to remove the reservoir and drain the collection completely.

DISCUSSION

Inflammatory reaction and subsequent erosion of an IPP reservoir is an infrequent but severe complication of IPP insertion, replacement or infection. Infection remains the primary indication for penile prosthesis removal and in this setting removal of the reservoir is routine. A thorough literature search has identified that in the non-infective setting, the routine removal of the original reservoir is not standard practice during three-component IPP replacement. In patients with a history of IPP presenting with new LUTS, reservoir erosion should be considered in the differential diagnosis and investigation with cystoscopy and computed tomography included early in the investigatory armament of the urologist.

CONCLUSION

It is our belief that a defunctionalized reservoir serves no purpose; rather it can only cause trouble in the future. Consequently, at our institution we do not leave defunctionalized reservoirs in situ.

Haemophagocytic syndrome after intravesical bacille Calmette-Guérin instillation

Abstract Intravesical bacille Calmette-Guérin (BCG) is used to treat high-risk superficial bladder cancer. This article reports a case of secondary haemophagocytosis after intravesical BCG instillation in a 70-year-old man with bladder cancer and presents a literature review of this very rare but potentially fatal complication of intravesical BCG treatment.

Urological applications of single-site laparoscopic surgery

Single-port, single-incision laparoscopy is part of the natural development of minimally invasive surgery. Refinement and modification of laparoscopic instrumentation has resulted in a substantial increase in the use of laparoendoscopic single-site surgery (LESS) in urology over the past 2 years. Since the initial report of single-port nephrectomy in 2007, the majority of laparoscopic procedures in urology have been described with a single-site approach. This includes surgery on the adrenal, ureter, bladder, prostate, and testis, for both benign and malignant conditions. In this review, we describe the current clinical applications and results of LESS in Urological Surgery. To date this evidence comes from small case series in centres of excellence, with good results. Further well-designed prospective trials are awaited to validate these findings.

Day-case and short-stay surgery: the future for thyroidectomy?

Day-case and short-stay thyroid surgery is carried out routinely around the world. In the UK longer postoperative stay is usually advocated to circumvent/identify potentially catastrophic complications following thyroidectomy. In the current climate of the National Health Service with focus on patient-centred service, reduced hospital stay and cost cutting, we conducted a review to provide a comprehensive assessment of day-case and short-stay thyroidectomy. A systematic electronic literature search using MEDLINE, Ovid, Embase, PubMed and Cochrane databases revealed 22 original studies that met our inclusion criteria. Generally studies demonstrated encouraging results regarding the feasibility of these approaches. Complication rates appeared equivocal to traditional longer stay thyroidectomy and only one patient died. The majority of life-threatening complications occurred in the immediate postoperative period. Of concern, some late haemorrhage has been documented at 5 days postsurgery. Complication rates following day-case/short-stay thyroid surgery appears comparable with inpatient thyroidectomy. Further study is required to determine whether this approach is truly safe.

Variations in the surface anatomy of the spinal accessory nerve in the posterior triangle

Iatrogenic injury to the spinal accessory nerve has been widely documented and can have medico-legal implications. The resulting syndrome of pain, paralysis and winging of the scapula are often the source of considerable morbidity. This paper researches the degree of accuracy achievable in mapping the surface anatomy of the spinal accessory nerve in the region of the posterior triangle with a view to creating a cartographical aid to surgical procedures. The necks of 25 adult cadavers were dissected bilaterally to expose the spinal accessory nerve. Variations in the course and distribution of the spinal accessory nerve in the posterior triangle were recorded along with its relationship to the borders of sternocleidomastoid and trapezius. Considerable variation was seen in the surface and regional anatomy of the nerve and in the contribution of the cervical plexus to the spinal accessory nerve in the posterior triangle. Measurements of the running course and exit point of the nerve into and from the posterior triangle differed significantly from those previously recorded. Delineation of an accurate surface anatomy was not possible. Creating a map to define the surface anatomy of the spinal accessory nerve in the posterior triangle is an unrealistic goal given its wide variations in man. Avoidance of damage to the spinal accessory nerve cannot be achieved by slavishly adhering to surface markings given in textbooks, but only by cautious dissection during operations on the posterior triangle.

Dystrophic ureteral calcification associated with Churg-Strauss vasculitis

Churg-Strauss syndrome is an uncommon systemic vasculitis affecting small blood vessels. Renal involvement is typical; however, calcinosis of the urinary tract has not previously been described. Dystrophic calcification in the urinary tract is rare, although it is occasionally associated with schistosomiasis, tuberculosis, and polyarteritis nodosa. We report the case of a 19-year-old man with newly diagnosed Churg-Strauss syndrome who presented to us with dystrophic calcification in both ureters causing bilateral obstruction.

Pelvi-calyceal height, a predictor of success when treating lower pole stones with extracorporeal shockwave lithotripsy

Extra corporeal shockwave lithotripsy (ESWL) is the treatment of choice for the majority of renal stones, however, it has the lowest success rate in complete clearance of stones located in the lower pole. We assess whether pelvi-calyceal height is a useful measurement in predicting successful stone clearance from the lower pole. A total of 105 patients with a solitary lower pole calculus of less than 20 mm treated with ESWL were reviewed. Stone size, location and pelvi-calyceal height were measured by intravenous urogram. Success was defined as complete stone clearance. Fifty-four patients (51.4%) had successful treatments, with the remaining 51 (48.6%) having incomplete stone clearance (including two patients in whom treatment had no effect). There was a statistically significant difference (P<0.0001) in pelvi-calyceal height between the two groups. Mean pelvi-calyceal height in patients with complete stone clearance was 15.1 mm (SD=3.9) compared with 22.9 mm (SD=5.2) for those with incomplete clearance. Pelvi-calyceal height is a useful predictor of success when treating lower pole renal stones with ESWL.

Surgical excision of isolated renal-bed recurrence after radical nephrectomy for renal cell carcinoma

OBJECTIVE

To present our results on managing loco-regional recurrence of renal cell carcinoma (RCC) with surgical excision, as local recurrence at the site of a previous nephrectomy is resistant to both systemic therapy and radiotherapy.

PATIENTS AND METHODS

In all, 16 patients were operated on between 1994 and 2003 for local recurrence of RCC. The median (mean, range) age at the time of local recurrence was 57.9 (57.4, 28.9-71.7) years, and the median interval from primary surgery 2.22 (3.88, 0.27-14.46) years. Before surgery eight patients had been given systemic immunotherapy, with no response of their local recurrence.

RESULTS

Two patients were deemed inoperable because of direct invasion of the great vessels and the liver by tumour. The remaining 14 patients had recurrence in residual adrenal tissue (two), para-aortic nodes (three), para-caval nodes (two), retrocaval nodes (one), renal bed (six), liver, spleen and stomach (one each), and diaphragm (two). Although complete macroscopic en-bloc clearance was achieved in these patients, only eight had tumour-free margins on histological examination. The histology was consistent with RCC recurrence in all cases. All of the patients were followed with computed tomography at regular intervals. At a median follow-up of 1.0 (1.65, 0.25-6.5) years, five patients remain disease-free, four have local and distant relapse, and five developed distant metastasis only. The presence of tumour at the resection margin was a significant factor in predicting local and distant disease-free survival (P < 0.05).

CONCLUSIONS

En bloc excision of isolated locally recurrent RCC is possible, and complete surgical extirpation can lead to prolonged disease-free survival.

Short-stay thyroid surgery

Achieved in 104 consecutive procedures

Percutaneous versus open tendo achillis repair

A retrospective analysis was conducted comparing open and percutaneous repair of ruptured Achilles tendon, over a 14-year period. One hundred and eight patients were identified; 70 underwent traditional open repair and 38 had a modified Ma & Griffith repair. The mean operating time with percutaneous repair was 28.5 minutes compared to 45.9 in the open group (p = <.0001). Comparable results were obtained in a subjective analysis of range of movement, stiffness, and power in both groups at time of discharge from clinic. In the open group there were four cases of rerupture (5.7%), four deep infections (4.7%), two palpable suture knots (2.9%), and one sural nerve lesion (1.4%). Complications with percutaneous repair included one rerupture (2.6%), five palpable suture knots (13.2%), four transient sural nerve lesions (10.5%), and no wound infections. There was no statistical significance between the two groups. The authors advocate percutaneous repair, in experienced hands, as a suitable alternative to traditional open techniques.

Percutaneous versus open tendo achillis repair

A retrospective analysis was conducted comparing open and percutaneous repair of ruptured Achilles tendon, over a 14-year period. One hundred and eight patients were identified; 70 underwent traditional open repair and 38 had a modified Ma & Griffith repair. The mean operating time with percutaneous repair was 28.5 minutes compared to 45.9 in the open group (p = <.0001). Comparable results were obtained in a subjective analysis of range of movement, stiffness, and power in both groups at time of discharge from clinic. In the open group there were four cases of rerupture (5.7%), four deep infections (4.7%), two palpable suture knots (2.9%), and one sural nerve lesion (1.4%). Complications with percutaneous repair included one rerupture (2.6%), five palpable suture knots (13.2%), four transient sural nerve lesions (10.5%), and no wound infections. There was no statistical significance between the two groups. The authors advocate percutaneous repair, in experienced hands, as a suitable alternative to traditional open techniques.

Leptin and TGF-beta synergistically regulate VIP cytokine response element transcription

Leptin was originally described as an adipocyte-derived cytokine that signals to the hypothalamus to regulate food intake and energy expenditure. Leptin signals through the Ob receptor, which is closely related to the gp130 cytokine receptor. Here we show that leptin can induce expression of the neuropeptide gene vasoactive intestinal peptide (VIP) through the VIP cytokine response element, the same element that mediates the response to the gp130 cytokines. Leptin acts synergistically with TGF-beta to activate transcription through this element. Transcriptional responses to leptin are increased when transmitted through ObR mutated at Tyr986, the SHP-2 docking domain, yet this mutation does not alter the synergy between TGF-beta and leptin. These data emphasize the functional similarity between leptin and the gp130 cytokines.

Enhancing leptin response by preventing SH2-containing phosphatase 2 interaction with Ob receptor

Leptin is an adipocyte-derived cytokine that regulates food intake and body weight via interaction with its Ob receptor (ObR). Serum leptin levels are chronically elevated in obese humans, suggesting that obesity may be associated with leptin resistance and the inability to generate an adequate ObR response. Evidence suggests that transcriptional activation of target genes by STAT3 (signal transducer and activator of transcription) in the hypothalamus is a critical pathway that mediates leptin's action. Herein we report that activation of ObR induces the tyrosine phosphorylation of the tyrosine phosphatase SH2-containing phosphatase 2 (SHP-2) and demonstrate that Tyr986 within the ObR cytoplasmic domain is essential to mediate phosphorylation of SHP-2 and binding of SHP-2 to ObR. Surprisingly, mutation of Tyr986 to Phe, which abrogates SHP-2 phosphorylation and binding to the receptor, dramatically increases gene induction mediated by STAT3. Our findings indicate that SHP-2 is a negative regulator of STAT3-mediated gene induction after activation of ObR and raise the possibility that blocking the interaction of SHP-2 with ObR could overcome leptin resistance by boosting leptin's weight-reducing effects in obese individuals.

NFAT interactions with the vasoactive intestinal peptide cytokine response element

The vasoactive intestinal peptide cytokine response element (VIP CyRE) is responsible for mediating the transcriptional induction of the VIP gene to the neuropoietic cytokines leukemia inhibitory factor (LIF) and ciliary neurotrophic factor (CNTF). In investigating the sequence and function of the CyRE, we found a region of DNA with homology to the distal NFAT site in the IL-2 promoter. In this paper we characterize this sequence and show that the VIP NFAT site recognizes T cell NFAT with similar affinity to the previously characterized IL-2 NFAT site. However, despite its location in the middle of the CyRE, we find no CNTF/LIF induced binding to it. Instead we show that in NBFL neuroblastoma cells, the calcium ionophore A23187 induces a protein to bind to the VIP NFAT site. This A23187-mediated induction of nuclear protein binding to an NFAT oligonucleotide is dependent on extracellular calcium but not dependent on de novo protein synthesis. Thus, this protein has the characteristics of an NFAT-like protein and is recognized by an NFAT3-specific antiserum suggesting that it is indeed an NFAT protein. The location of the NFAT site in the VIP CyRE suggests that this may be one mechanism through which different signaling pathways engage in cross talk to alter VIP gene transcription.

Coordinate regulation of STAT signaling and c-fos expression by the tyrosine phosphatase SHP-2

The src homology 2 (SH2) domain-containing protein-tyrosine phosphatase SHP-2 has been implicated as an important positive regulator of several mitogenic signaling pathways. SHP-2 has more recently been shown to be tyrosine phosphorylated and recruited to the gp130 component of the ciliary neurotrophic factor (CNTF) receptor complex upon stimulation with CNTF. CNTF does not, however, have a proliferative effect on responsive cells, but rather enhances the survival and differentiation of sympathetic, motor, and sensory neurons. In this study, expression of an interfering mutant of SHP-2 in the neuroblastoma cell line NBFL increased CNTF induction of a vasoactive intestinal peptide (VIP) reporter gene, and in cultures of sympathetic neurons, it resulted in an up-regulation of endogenous VIP and substance P (SP) gene expression. Members of the CNTF family of cytokines transmit their signal by activating signaling pathways involving both STAT and Fos-Jun transcription factors. In CNTF-stimulated NBFL cells that constitutively express the SHP-2 interfering mutant, there was increased and prolonged formation of STAT/DNA complexes, but decreased AP-1 binding activity, that mirrored a down-regulation of c-fos expression both at the mRNA and protein level. Taken together, these data indicate that SHP-2 has dual and opposing roles in a signaling cascade triggered by the same ligand, as illustrated by its ability to differentially regulate the levels of activity of both STAT and AP-1 transcription factors.

The protein tyrosine phosphatase SHP-2 negatively regulates ciliary neurotrophic factor induction of gene expression

Ciliary neurotrophic factor, along with other neuropoietic cytokines, signals through the shared receptor subunit gp130 [1-3], leading to the tyrosine phosphorylation of a number of substrates [4,5], including the transcription factors STAT1 and STAT3 and the protein tyrosine phosphatase SHP-2 [6,7] [8]. SHP-2 (also known as PTP1D, SHPTP2, Syp and PTP2C) is a positive regulatory molecule required for the activation of the mitogen-activated protein kinase pathway and the stimulation of gene expression in response to epidermal growth factor, insulin and platelet-derived growth factor stimulation [9-11]. We have previously shown that cytokines that signal via the gp130 receptor subunit activate transcription of the vasoactive intestinal peptide (VIP) gene through a 180 bp cytokine response element (CyRE) [12,13]. To characterize the role of SHP-2 in the regulation of gp130-stimulated gene expression, we examined the regulation of the VIP CyRE in two systems that prevented ligand-dependent SHP-2 phosphorylation. Inhibition of SHP-2, either by mutating the tyrosine residue in gp130 that mediates the SHP-2 interaction, or by expression of dominant-negative SHP-2, resulted in dramatic increases in gp130-dependent gene expression, through the VIP CyRE and more specifically through multimerized STAT-binding sites. These data suggest that SHP-2 has a negative role in gp130 signaling by modulating STAT-mediated transcriptional activation.

Integration of Jak-Stat and AP-1 signaling pathways at the vasoactive intestinal peptide cytokine response element regulates ciliary neurotrophic factor-dependent transcription

Ciliary neurotrophic factor (CNTF)-dependent induction of expression of the neuropeptide vasoactive intestinal peptide (VIP) gene is mediated by a 180-base pair cytokine response element (CyRE) in the VIP promoter. To elucidate the molecular mechanisms mediating the transcriptional activation by CNTF, intracellular signaling to the CyRE has been studied in a neuroblastoma cell line. It has been shown previously that CNTF induces Stat proteins to bind to a site within the CyRE. CNTF also induces a second protein to bind to a C/EBP-like site within the CyRE. In this report, we show that this inducible CyRE binding protein is composed of the AP-1 proteins c-Fos, JunB, and JunD. These proteins bind to a non-canonical AP-1 site located near the previously characterized C/EBP site. The serine/threonine kinase inhibitor H7 prevents CNTF-dependent induction of AP-1 binding and CyRE-mediated transcription, suggesting that an H7-sensitive kinase is important to mediating CNTF effects on VIP transcription. The integration at the VIP CyRE of the Jak-Stat and AP-1 signaling pathways with other pre-existing proteins provides a cellular mechanism for cell- and cytokine-specific signaling.

A minimal CGRP gene promoter is inducible by nerve growth factor in adult rat dorsal root ganglion neurons but not in PC12 phaeochromocytoma cells

The calcitonin/CGRP gene is transcribed in thyroid C cells and some neuronal cells but not in other cell types. Although the promoter sequences mediating gene activity in thyroid C cells have been extensively studied, the elements responsible for promoter activity in neuronal cells and its stimulation by nerve growth factor (NGF) have not previously been defined. We report the first use of the calcium phosphate procedure to successfully transfect adult rat dorsal root ganglion neurons, which naturally express the calcitonin/calcitonin gene-related peptide (CGRP) in an NGF-inducible manner. This method was used to characterize the elements in the calcitonin/CGRP promoter which are responsible for its basal activity and NGF inducibility in DRG neurons and in PC12 cells, a neuronally derived cell line which does not naturally express the calcitonin/CGRP gene. Although the sequences required for basal activity are similar in each cell type, we show that a minimal calcitonin/CGRP promoter is NGF-responsive in dorsal root ganglion cells, but that upstream sequences are required for such inducibility in PC12 cells.

STAT proteins participate in the regulation of the vasoactive intestinal peptide gene by the ciliary neurotrophic factor family of cytokines

Ciliary neurotrophic factor (CNTF) and leukemia inhibitory factor (LIF) are members of a family of neuropoietic cytokines that have a broad range of actions on many different neuronal populations. In cultured sympathetic neurons, CNTF and LIF induce transcription of the VIP and other neuropeptide genes as part of a program of differentiation. To gain insight into the nuclear events involved in cytokine-mediated activation of the neuropeptide genes involved in neuronal differentiation, we have investigated the mechanisms of transcriptional activation of the vasoactive intestinal peptide (VIP) gene by the CNTF family of cytokines. In the neuroblastoma cell line NBFL, CNTF, LIF, and a related cytokine, oncostatin-M, activate VIP gene transcription through a 180-base pair cytokine response element (CyRE). Deletion analysis of the VIP CyRE showed that multiple regions within the 180 base-pairs are important for cytokine-mediated transcriptional activation of the VIP gene. To one of these regions within the CyRE, cytokine treatment induces binding of a protein complex composed of members of the signal transducers and activators of transcription (STAT) transcription factor family. Mutation of this STAT-binding site attenuates cytokine-mediated transcriptional activation. LIF treatment of primary sympathetic neurons also induced binding of a STAT-containing protein complex to the VIP CyRE. Thus, activation of STAT transcription factors contributes to the induction of the VIp gene by the CNTF family of cytokines and may be involved in cytokine-mediated differentiation of sympathetic neurons.

Oncostatin M regulates VIP expression in a human neuroblastoma cell line

Oncostatin-M (OM), a recently described glycoprotein cytokine, is structurally and functionally related to cholinergic differentiation factor/leukemia inhibitory factor (CDF/LIF) and ciliary neurotrophic factor (CNTF). To determine whether OM, like CDF/LIF and CNTF, possesses trophic or differentiative functions for neurons we examined the effects of recombinant human OM on ciliary neuron survival and neurotransmitter expression in sympathetic neurons. Like CDF/LIF, but in contrast to CNTF, OM had no effect on ciliary neuronal survival at any concentration tested. OM produced small but reproducible increases in choline acetyl transferase (ChAT) activity and vasoactive intestinal peptide (VIP) levels in rat sympathetic neuron cultures, but this effect was significantly less than that of CNTF or CDF/LIF. To determine if human OM would elicit a more robust response from human cells, we utilized a human neuroblastoma cell line, NBFL, that responds to CNTF and CDF/LIF by altering vasoactive intestinal peptide (VIP) levels. OM specifically elevated VIP and c-fos mRNA levels in NBFL cells and was as potent as CDF/LIF in this assay. Our data provides evidence that OM acts on neurons and identifies a neural cell line responsive to OM, CNTF, CDF/LIF.

Toxic nephropathy after low-dose methoxyflurane anesthesia: drug interaction with secobarbital?

Vasopressin-resistant nonoliguric renal insufficiency developed in a 57-year-old man after 2 1/2 hours of low-dose methoxyflurane anesthesia. Secobarbital, 100 mg daily, had been taken for 1 month before. Of 13 patients in whom the influence of methoxyflurane on renal function was being studied, he was the only one to have taken a drug that induces microsomal enzymes. Blood values of methoxyflurane in this patient were lower than group means on all five occasions during anesthesia. Postoperatively his serum inorganic fluoride value reached 114 mumol/l -- more than two standard deviations greater than the group mean. Peak values for serum urea nitrogen, creatinine and uric acid and postvasopressin urine osmolality, and the lowest creatinine clearance in this patient also differed by more than 2 SD from the group mean, and the peak amount of oxalate excreted in his urine was double the group mean. Pretreatment with the barbiturate appears to have altered methoxyflurane metabolism and led to toxic concentrations of metabolites in the blood.