Disruption of IL-17-mediated immunosurveillance in the respiratory mucosa results in invasive Streptococcus pyogenes infection

Introduction

Streptococcus pyogenes is a Gram-positive pathogen that causes a significant global burden of skin pyoderma and pharyngitis. In some cases, infection can lead to severe invasive streptococcal diseases. Previous studies have shown that IL-17 deficiency in mice (IL-17-/-) can reduce S. pyogenes clearance from the mucosal surfaces. However, the effect of IL-17 on the development of severe invasive streptococcal disease has not yet been assessed.

Methods

Here, we modeled single or repeated non-lethal intranasal (IN) S. pyogenes M1 strain infections in immunocompetent and IL-17-/- mice to assess bacterial colonization following a final IN or skin challenge.

Results

Immunocompetent mice that received a single S. pyogenes infection showed long-lasting immunity to subsequent IN infection, and no bacteria were detected in the lymph nodes or spleens. However, in the absence of IL-17, a single IN infection resulted in dissemination of S. pyogenes to the lymphoid organs, which was accentuated by repeated IN infections. In contrast to what was observed in the respiratory mucosa, skin immunity did not correlate with the systemic levels of IL-17. Instead, it was found to be associated with the activation of germinal center responses and accumulation of neutrophils in the spleen.

Discussion

Our results demonstrated that IL-17 plays a critical role in preventing invasive disease following S. pyogenes infection of the respiratory tract.

A Glycolipidated-liposomal peptide vaccine confers long-term mucosal protection against Streptococcus pyogenes via IL-17, macrophages and neutrophils

Mucosally active subunit vaccines are an unmet clinical need due to lack of licensed immunostimulants suitable for vaccine antigens. Here, we show that intranasal administration of liposomes incorporating: the Streptococcus pyogenes peptide antigen, J8; diphtheria toxoid as a source of T cell help; and the immunostimulatory glycolipid, 3D(6-acyl) PHAD (PHAD), is able to induce long-lived humoral and cellular immunity. Mice genetically deficient in either mucosal antibodies or total antibodies are protected against S. pyogenes respiratory tract infection. Utilizing IL-17-deficient mice or depleting cellular subsets using antibodies, shows that the cellular responses encompassing, CD4+ T cells, IL-17, macrophages and neutrophils have important functions in vaccine-mediated mucosal immunity. Overall, these data demonstrate the utility of a mucosal vaccine platform to deliver multi-pronged protective responses against a highly virulent pathogen.

Streptolysin O Deficiency in Streptococcus pyogenes M1T1 covR/S Mutant Strain Attenuates Virulence in In Vitro and In Vivo Infection Models

Mutation within the Streptococcus pyogenes (Streptococcus group A; Strep A) covR/S regulatory system has been associated with a hypervirulent phenotype resulting from the upregulation of several virulence factors, including the pore-forming toxin, streptolysin O (SLO). In this study, we utilized a range of covR/S mutants, including M1T1 clonal strains (5448 and a covS mutant generated through mouse passage designated 5448AP), to investigate the contribution of SLO to the pathogenesis of covR/S mutant Strep A disease. Up-regulation of slo in 5448AP resulted in increased SLO-mediated hemolysis, decreased dendritic cell (DC) viability post coculture with Strep A, and increased production of tumor necrosis factor (TNF) and monocyte chemoattractant protein 1 (MCP-1) by DCs. Mouse passage of an isogenic 5448 slo-deletion mutant resulted in recovery of several covR/S mutants within the 5448Δslo background. Passage also introduced mutations in non-covR/S genes, but these were considered to have no impact on virulence. Although slo-deficient mutants exhibited the characteristic covR/S-controlled virulence factor upregulation, these mutants caused increased DC viability with reduced inflammatory cytokine production by infected DCs. In vivo, slo expression correlated with decreased DC numbers in infected murine skin and significant bacteremia by 3 days postinfection, with severe pathology at the infection site. Conversely, the absence of slo in the infecting strain (covR/S mutant or wild-type) resulted in detection of DCs in the skin and attenuated virulence in a murine model of pyoderma. slo-sufficient and -deficient covR/S mutants were susceptible to immune clearance mediated by a combination vaccine consisting of a conserved M protein peptide and a peptide from the CXC chemokine protease SpyCEP. IMPORTANCE Streptococcus pyogenes is responsible for significant numbers of invasive and noninvasive infections which cause significant morbidity and mortality globally. Strep A isolates with mutations in the covR/S system display greater propensity to cause severe invasive diseases, which are responsible for more than 163,000 deaths each year. This is due to the upregulation of virulence factors, including the pore-forming toxin streptolysin O. Utilizing covR/S and slo-knockout mutants, we investigated the role of SLO in virulence. We found that SLO alters interactions with host cell populations and increases Strep A viability at sterile sites of the host, such as the blood, and that its absence results in significantly less virulence. This work underscores the importance of SLO in Strep A virulence while highlighting the complex nature of Strep A pathogenesis. This improved insight into host-pathogen interactions will enable a better understanding of host immune evasion mechanisms and inform streptococcal vaccine development programs.

Prime-Pull Immunization with a Bivalent M-Protein and Spy-CEP Peptide Vaccine Adjuvanted with CAF®01 Liposomes Induces Both Mucosal and Peripheral Protection from covR/S Mutant Streptococcus pyogenes

Infections with Streptococcus pyogenes and their sequelae are responsible for an estimated 18 million cases of serious disease with >700 million new primary cases and 500,000 deaths per year. Despite the burden of disease, there is currently no vaccine available for this organism. Here, we define a combination vaccine P*17/K4S2 comprising of 20-mer B-cell peptide epitopes, p*17 (a mutant derived from the highly conserved C3-repeat region of the M-protein), and K4S2 (derived from the streptococcal anti-neutrophil factor, Spy-CEP). The peptides are chemically conjugated to either diphtheria toxoid (DT) or a nontoxic mutant form of diphtheria toxin, CRM197. We demonstrate that a prime-pull immunization regimen involving two intramuscular inoculations with P*17/K4S2 adjuvanted with a two-component liposomal adjuvant system (CAF01; developed by Statens Serum Institut [SSI], Denmark), followed by an intranasal inoculation of unadjuvanted vaccine (in Tris) induces peptide- and S. pyogenes-binding antibodies and protects from mucosal and skin infection with hypervirulent covR/S mutant organisms. Prior vaccination with DT does not diminish the response to the conjugate peptide vaccines. Detailed Good Laboratory Practice (GLP) toxicological evaluation in male and female rats did not reveal any gross or histopathological adverse effects.IMPORTANCE A vaccine to control S. pyogenes infection is desperately warranted. S. pyogenes colonizes the upper respiratory tract (URT) and skin, from where it can progress to invasive and immune-mediated diseases. Global mortality estimates for S. pyogenes-associated diseases exceeds 500,000 deaths per year. S. pyogenes utilizes antigenic variation as a defense mechanism to circumvent host immune responses and thus a successful vaccine needs to provide strain-transcending and multicompartment (mucosal and skin) immunity. By defining highly conserved and protective epitopes from two critical virulence factors (M-protein and Spy-CEP) and combining them with a potent immunostimulant, CAF®01, we are addressing an unmet clinical need for a mucosally and skin-active subunit vaccine. We demonstrate that prime-pull immunization (2× intramuscular injections followed by intranasal immunization) promotes high sustained antibody levels in the airway mucosa and serum and protects against URT and invasive disease.

Author Correction: M-protein based vaccine induces immunogenicity and protection from Streptococcus pyogenes when delivered on a high-density microarray patch (HD-MAP)

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Qualitative study of clinician and patient perspectives on the mode of anaesthesia for emergency surgery

Background

Although delivering a chosen mode of anaesthesia for certain emergency surgery procedures is potentially beneficial to patients, it is a complex intervention to evaluate. This qualitative study explored clinician and patient perspectives about mode of anaesthesia for emergency surgery.

Methods

Snowball sampling was used to recruit participants from eight National Health Service Trusts that cover the following three emergency surgery settings: ruptured abdominal aortic aneurysms, hip fractures and inguinal hernias. A qualitative researcher conducted interviews with clinicians and patients. Thematic analysis was applied to the interview transcripts.

Results

Interviews were conducted with 21 anaesthetists, 21 surgeons, 14 operating theatre staff and 23 patients. There were two main themes. The first, impact of mode of anaesthesia in emergency surgery, had four subthemes assessing clinician and patient ideas about: context and the ‘best’ mode of anaesthesia; balance in choosing it over others; change and developments in anaesthesia; and the importance of mode of anaesthesia in emergency surgery. The second, tensions in decision‐making about mode of anaesthesia, comprised four subthemes: clinical autonomy and guidelines in anaesthesia; conforming to norms in mode of anaesthesia; the relationship between expertise, preference and patient involvement; and team dynamics in emergency surgery. The results highlight several interlinking factors affecting decision‐making, including expertise, preference, habit, practicalities, norms and policies.

Conclusion

There is variation in practice in choosing the mode of anaesthesia for surgery, alongside debate as to whether anaesthetic autonomy is necessary or results in a lack of willingness to change.

Moral reasoning and decision-making in adolescents who sustain traumatic brain injury

Objective: Emerging evidence suggests that moral processes are disrupted by traumatic brain injury (TBI). The objective of this study was to explore moral reasoning (MR) and decision-making in adolescents with TBI, and to examine potential associations with global manifestations of social competence.Design: This retrospective, cross-sectional research design compared MR and decision-making in adolescents with mild TBI (n = 20), moderate-severe TBI (n = 23) and typically developing controls (n = 93).Methods: Participants completed a visual task of socio-moral reasoning (SoMoral) and the Index of Empathy for Children and Adolescents. Their parents completed questionnaires documenting their child's behavior (Child Behavior Checklist) and adaptive functioning (Adaptive Behavior Assessment System-Second Edition).Main results: Adolescents with both mild and moderate-severe TBI displayed more immature MR than typically developing peers. Participants with TBI also provided fewer socially adapted decisions. Closer inspection revealed that this difference was apparent only in the mild TBI group. No significant group differences were observed for empathy, behavior or adaptive skills.Conclusions: Sustaining TBI appears to affect adolescents' ability to provide mature moral justifications when faced with moral dilemmas representative of everyday social conflicts. These difficulties do not appear to be associated with behavior problems, reduced empathy, or adaptive functioning.

Programmed cell death-1 expression correlates with disease severity and IL-5 in chronic rhinosinusitis with nasal polyps

BACKGROUND

Programmed cell death-1 (PD-1) is a negative regulator of T-cell responses. Expression of PD-1 and its ligands PD-L1 and PD-L2 in chronic rhinosinusitis with nasal polyps (CRSwNP) is poorly studied.

METHODS

Expression of PD-1, PD-L1, PD-L2, TGF-β, IL-5, and IL-10 mRNA was measured by real-time quantitative PCR on tissue homogenates of patients with CRSwNP (n = 21) and healthy controls (n = 21) and on primary epithelial cells. Disease severity was scored using the Lund-Mackay scores of maxillofacial computed tomography (CT) scans. Expression of PD-1 and PD-L1/L2 was evaluated at the cellular and tissue levels (n = 6) by flow cytometry and immunohistochemistry.

RESULTS

Programmed cell death-1 mRNA expression was increased in tissue homogenates from patients with CRSwNP compared with controls, irrespective of the atopy status. Importantly, expression of PD-1 correlated with the total CT scan scores (r = 0.5, P = 0.02). Additionally, a significant association was found between PD-1 mRNA and expression of IL-5 mRNA in control nasal tissue (r = 0.95, P < 0.0001) and in CRSwNP (r = 0.63, P = 0.002). PD-1 was expressed on different subsets of T cells and CD11b^- dendritic cells. Both PD-1 and its ligands were expressed on primary epithelial cells from control nasal tissue and nasal polyp tissue.

CONCLUSIONS

Higher PD-1 expression was found in CRSwNP than in nasal tissue from controls. This was associated with disease severity and tissue IL-5 expression but unrelated to the patients' atopy status.

Improving Film Die Flow Uniformity Using Optimization Methods Coupled with Finite Element Computational Fluid Dynamics (CFD) Analysis

The aim of this study was to evaluate various optimization strategies to be used with computational fluid dynamics (CFD), in order to optimize the geometry for a polymer die to meet the dual objectives of uniform flow at the exit with minimal pressure drop. 3D finite element simulations using the numerically optimized geometry predict a more uniform flow than simulations using the baseline geometry. However, some of the initial optimized results yielded die geometries that would be impractical to fabricate. Additional constraints were placed on the allowable geometric parameters and solution space to push the optimization towards more feasible optimal solutions. Thus we have shown how CFD-based optimization methods, coupled with knowledge of die design technology and fabrication techniques can lead to the design of better performing polymer dies.

Rural and remote obstetric care close to home: program description, evaluation and discussion of Sioux Lookout Meno Ya Win Health Centre obstetrics

PROBLEM BEING ADDRESSED

Aboriginal and non-Aboriginal women in rural and remote settings struggle to access obstetric care close to home. Objective of the program: To deliver a full range of modern and safe obstetric care to 28 remote Aboriginal communities served by rural-based health care.

PROGRAM DESCRIPTION

Rural family physicians provide intrapartum, cesarean delivery and anesthesia services to 350 rural, primarily Aboriginal women in a collegial, supportive environment.

CONCLUSION

Rural and remote obstetric services need support before they fail. Patient volume, remote location and organizational culture are key elements. Evidence teaches us that outcomes are best when women deliver closer to home.

Health information seeking and its effect on the doctor-patient digital divide

A survey of 224 individuals using SureStart services (for young families) within an inner-London area was complemented by qualitative data from five focus groups of parents and general practitioners in the same area. Descriptive and multivariate statistics were used to identify and describe discrete geographical districts with differing patterns of health information seeking. A geographically defined group of 'information hungry'/'online' health seekers was identified. This group contrasted with those acquiring information through 'assimilation' ('offline' information seekers). Qualitative data revealed the processes underpinning these characteristics and professional attitudes towards the Internet as a source of health information.

Health visiting at the crossroads: which way to the 21st century?

This article presents a response from a group of lecturers at Florence Nightingale School of Nursing and Midwifery, King's College London and one service user to the perception of a crisis of confidence within health visiting. Changes in registration procedures and shifts in policy have led health visiting to question its place within primary care and the model of preparation for health visiting practice. The group argues that this debate is based on a misunderstanding of the changing health care environment and that health visiting can find a place within the primary care team. Key to this is the continued adherence to a basic nursing training. The authors suggest an incremental model of health visitor training to provide the fullest scope to implement the new health agenda.

Successful PCR amplification of genomic DNA from Cryptosporidium parvum oocysts extracted from a human faecal sample: a rapid and simple method suited for outbreak analysis

A method to extract genomic DNA from oocysts of Cryptosporidium parvum in human faecal material was developed and consisted of a simple alkali wash, freeze/boil technique. This method was simple, quick, sensitive, inexpensive and resulted in the production of genomic DNA which was free of PCR inhibitors and as such was a suitable template for the detection of C. parvum by various PCR amplification targets.

Prognostic significance of failure of the initial antiepileptic drug in children with absence epilepsy

PURPOSE

In children with childhood absence epilepsy (CAE) and juvenile absence epilepsy (JAE), to determine the impact of failure of initial antiepileptic drug (AED) for lack of efficacy in eventual seizure control and long-term remission of epilepsy.

METHODS

Centralized EEG records for the province of Nova Scotia allowed identification of all children seen with CAE or JAE between 1977 and 1985. Information regarding success or failure of initial AED in fully controlling seizures and long-term seizure control and remission of epilepsy was collected by patient questionnaire and chart review.

RESULTS

Eighty-six of 92 eligible patients were followed up (75 CAE, 11 JAE). Initial AED treatment was successful in 52 (60%) of 86. Success tended to be greater for valproate (VPA) than for other AEDs (p = 0.07), and lower if generalized tonic-clonic or myoclonic seizures coexisted (p < 0.004 and p < 0.03). Terminal remission was more likely if the initial AED was successful than if it had failed (69% vs. 41%; p < 0.02). Compared with those in whom the initial AED was successful, subjects whose initial AED had failed were more likely to progress to juvenile myoclonic epilepsy (JME) at last follow-up (32% vs. 10%; p < 0.02) and to develop intractable epilepsy (17% vs. 2%; p < 0.04).

CONCLUSIONS

Initial AED was successful in 60% of children with AE. If the first AED failed, the outcome was less favorable, with a lower rate of terminal remission and a higher rate of progression to JME and intractable epilepsy.

Image-guided radiosurgery for the spine and pancreas

A robotic image-guided radiosurgical system has been modified to treat extra-cranial sites using implanted fiducials and skeletal landmarks to locate the treatment targets. The system has been used to treat an artero-venous malformation in the cervical spine, a recurrent schwannoma of the thoracic spine, a metastatic adenocarcinoma of the lumbar spine, and three pancreatic cancers. During each treatment, the image guidance system monitored the position of the target site and relayed the target coordinates to the beam-pointing system at discrete intervals. The pointing system then dynamically aligned the therapy beam with the lesion, automatically compensating for shifts in target position. Breathing-related motion of the pancreas lesions was managed by coordinating beam gating with breath-holding by the patient. The system maintained alignment with the spine lesions to within +/- 0.2 mm on average, and to within +/- 1 mm for the pancreatic tumors. This experience has demonstrated the feasibility of using image-guided robotic radiosurgery outside the cranium.

Effects of a structured curriculum in osteopathic manipulative treatment (OMT) on osteopathic structural examinations and use of OMT for hospitalized patients

Osteopathic manipulative treatment (OMT) is a defining feature of osteopathic medicine; however, use of OMT by osteopathic physicians is declining. Recent studies reveal that many osteopathic physicians are abandoning use of OMT as early as medical school. Current national efforts are aimed at reversing this trend by standardizing osteopathic medical records and clinical training in OMT. The authors found that a structured clinical curriculum in OMT taught to house staff significantly increased the percentage of patients who received osteopathic structural examinations and the percentage of patients who received OMT as part of their hospital care.

Anti-Yo positive paraneoplastic cerebellar degeneration associated with ovarian carcinoma: case report and review of the literature

Paraneoplastic cerebellar degeneration (PCD) is a rare nonmetastatic neurological complication in cancer patients. Anti-Yo is one of the anti-onconeural antibodies found in PCD patients. It is believed that anti-Yo occurs almost always in women and is most likely associated with gynecologic or breast cancers, although exceptions exist. Here we report a PCD patient with ovarian cancer having high-titer anti-Yo. The acute onset of her PCD symptoms mimicked that of a stroke. Her ovarian cancer tissue contained abundant plasma cells and lymphocytes. After a thorough review of the literature, we propose a schematic hypothesis for the autoimmune pathogenesis of PCD. Despite anecdotal case reports of neurological improvement with different combinations of treatment, including IVIg, there is still no definitely effective treatment for PCD. Further research on the pathogenesis of PCD may lead to more effective therapies.

Results of percutaneous plastic stents for malignant distal biliary obstruction following failed endoscopic stent insertion and comparison with current literature on expandable metallic stents

BACKGROUND

Endoscopic stenting is an effective method of relieving biliary obstruction in patients with unresectable malignancy. If this fails, optimal management is controversial. Percutaneous insertion of plastic or mesh metal stents has been advocated.

AIM

To review the outcome of percutaneous plastic stents and compare this with contemporary data from the literature on mesh metal stenting.

PATIENTS AND METHODS

Over a period of six years, 400 patients had attempted endoscopic stenting for distal malignant biliary obstruction which failed in 54 (13.5%). These 54 patients were treated with percutaneously placed plastic stents.

RESULTS

Percutaneous stenting was technically successful in 48 patients (89%). Early complications occurred in 13 patients (24%), the commonest being acute cholangitis in seven (12%). There was no procedure-related mortality but a 30-day mortality of 11 % (n = 6). Ten patients (18%) required re-admission after 30 days for stent block (mean period 4 months). Forty-seven patients (87%) were followed up until death. The median survival for the patients undergoing palliative stenting was 3 months (5 days to 17 months).

CONCLUSIONS

These results suggest that percutaneous plastic stents can be used safely and effectively in patients who have failed endoscopic stenting.

The Sioux Lookout Diabetes Program: diabetes prevention and management in northwestern Ontario

Clinically, non-insulin-dependent diabetes mellitus (NIDDM) in the First Nations population of the Sioux Lookout Zone (SLZ), Northwestern Ontario, represents a very different entity than that found in the general Canadian population. Here, its prevalence reaches upwards of 17% (over the age of 10) and children as young as five years of age have been diagnosed. Diabetic ketoacidosis is frequently found, and clients with blood glucose levels of 50 mmol/L or more have remained asymptomatic. Prevention and management of NIDDM in the SLZ must reflect this reality, as well as those of geographic remoteness; community-specific needs; and cultural, in addition to personal, relevance. Over the past five years, the Sioux Lookout Diabetes Program has been developing innovative services and resources to address these needs. Traveling foot-care and diabetes education programs, Community Health Representative training programs, a youth camp, school programs, grocery store labeling programs, and culturally relevant education manuals are a few such initiatives. Visions for the future include the development of a network of community-based diabetes workers to address more completely prevention and management needs on an ongoing basis and the development of stress management workshops for First Nations clients. With our current programming, these new initiatives, and an aggressive early screening program, we hope to stem the imminent onslaught of amputations, heart attacks, renal failure, and blindness.

Gestational diabetes and subsequent development of NIDDM in aboriginal women of northwestern Ontario

OBJECTIVES

To determine (1) the risk of development of non-insulin-dependent diabetes mellitus (NIDDM) in women with a previous history of gestational diabetes mellitus (GDM), (2) the average duration between diagnoses of GDM and NIDDM, (3) various modes of presentation, and (4) adequacy of follow-up post diagnosis of GDM.

METHODS

A retrospective chart review of women diagnosed with GDM in the Sioux Lookout Zone between 1985-1995. There were 4,211 pregnancies and 332 women with a diagnosis of GDM. Sixty-one charts were randomly selected. Both GDM and NIDDM were defined according to World Health Organization standards.

RESULTS

Seventy percent of the women with GDM went on to develop NIDDM. The average duration between diagnosis of GDM and diagnosis of NIDDM was three years. Greater than 70% of the women developed NIDDM within four years post diagnosis of GDM. The majority presented with asymptomatic hyperglycemia (88%); 3% presented with acidosis; 6% presented with symptoms of polydipsia and polyuria; and 3% presented with abnormal weight gain. Specific physician-requested follow-up after six weeks postpartum occurred in only 38% of the cases. However six-week follow-up occurred in 41%, a yearly follow-up occurred in 61% of the women, and 81% of the women had some sort of follow-up post diagnosis of GDM.

CONCLUSIONS

The risk of developing NIDDM after GDM is very high in Aboriginal women of the Sioux Lookout Zone. There is an urgent need for a structured follow-up program for this group of high-risk women. Furthermore, the offspring of these pregnancies should be a focus for follow-up and preventive programs.

A review of nonclinical toxicology studies of becaplermin (rhPDGF-BB)

Becaplermin (recombinant human platelet-derived growth factor-BB [BB homodimer, rhPDGF-BB]) has demonstrated a favorable safety profile in a series of nonclinical studies designed to assess its systemic toxicity, sensitization, local irritation, and genotoxic potential. No significant local or systemic toxicity directly attributable to becaplermin was observed following single and multiple intravenous or subcutaneous administration at doses up to 3 mg/kg in monkeys. Administration of single large intravenous doses (up to 100 mg/kg) and repeated dosing at 1 or 3 mg/kg in mice resulted in rapidly reversible vasodilation and central nervous system depression. In a bone-toxicity study, becaplermin produced histomorphologic changes suggestive of accelerated bone remodeling, which were judged to be potentially reversible. Similar findings have not been observed in humans. Although becaplermin was not considered a dermal or ocular irritant, some skin-sensitizing effects were observed in animals; this finding was not unexpected for a recombinant human-derived protein. Becaplermin was not genotoxic in a variety of in vitro assays and in one in vivo assay.

Juvenile rheumatoid arthritis in a Canadian First Nations (aboriginal) population: onset subtypes and HLA associations

OBJECTIVE

To determine onset subtypes and HLA associations of juvenile rheumatoid arthritis (JRA) in a First Nations (aboriginal) population; to determine whether population frequencies of HLA antigens may explain the distribution of subtypes of JRA in this population.

METHODS

All patients were children from Manitoba and Northwestern Ontario seen in a single pediatric rheumatology clinic between 1975 and 1996. Patients were identified from a clinic registry. Controls were adults of Algonkian Cree and Ojibway heritage. Class I and II major histocompatibility (HLA) typing was performed for First Nations patients and controls.

RESULTS

There were a total of 74 First Nations patients with JRA. The relative frequency of rheumatoid factor (RF) positive polyarticular JRA was higher and that of pauciarticular JRA was lower in First Nations compared with Caucasian patients (42 versus 3% and 22 versus 58%, respectively; p = 0.00000). HLA-DRB1*04 (63%), 08 (43%), and 1402 (25%) were the most common DRB1 antigens among controls. The main subtypes of DRB1*04 were 0404 (33% of controls) and 0407 (23%). HLA typing was performed for 39 First Nations patients; 27 were Cree or Ojibway, 4 were from other tribes, and 8 were part First Nations. Among Cree and Ojibway, 59% of controls and 63% of patients with RF positive polyarticular JRA (n = 16) had HLA-DRB1 antigens bearing the rheumatoid arthritis (RA) shared epitope (OR 1.16, 95% CI: 0.38, 3.48). The OR for polyarticular RF positive JRA in those with DRB1*0802 and 0901 were 0.15, 95% CI: 0.02; and 1.24 and 5.83, 95% CI: 1.58, 28.38, respectively.

CONCLUSION

There was a high frequency of the RA shared epitope represented by both HLA-DRB1*0404 and 1402 in this Algonkian population. This high frequency may explain the high frequency of RF positive polyarticular JRA. DRB1*0802 may be protective, whereas DRB1*0901 may increase the risk for this subtype of JRA.

Prospective study of hepatobiliary scintigraphy and endoscopic cholangiography for the detection of early biliary complications after orthotopic liver transplantation

BACKGROUND

Biliary complications are a significant cause of morbidity and death after orthotopic liver transplantation (OLT). This study was a prospective evaluation of endoscopic retrograde cholangiography (ERC) and hepatobiliary scintigraphy (HBS), using 99mTc Mebrofenin, to detect early biliary complications following OLT.

METHODS

One hundred consecutive patients who had OLT with a biliary duct-to-duct anastomosis were studied. Of these, 67 had both ERC and HBS performed within 30 days of OLT. Sensitivity, specificity and diagnostic accuracy of HBS in identifying biliary leak or stricture was calculated.

RESULTS

Of the 67 cholangiographies performed 45 were normal. In 22 patients there was radiological evidence of a leak (n = 14) or stricture (n = 8) which required further intervention in nine and four patients respectively. The sensitivity and specificity of scintigraphy for the detection of biliary leak after transplantation was 50 and 79 per cent and for biliary stricture 62 and 64 per cent respectively. No patient with normal scintigraphy required biliary intervention. Only six of 14 patients with biliary leaks and two of 20 with strictures suggested by scintigraphy required intervention. If both ERC and HBS reported leak or stricture, the intervention rate was considerably higher at five of seven leaks and two of five strictures.

CONCLUSION

This study suggests that scintigraphy is a useful screening test for biliary complications after OLT, ERC is only necessary if HBS is abnormal.

Prospective study of hepatobiliary scintigraphy and endoscopic cholangiography for the detection of early biliary complications after orthotopic liver transplantation

BACKGROUND

Biliary complications are a significant cause of morbidity and death after orthotopic liver transplantation (OLT). This study was a prospective evaluation of endoscopic retrograde cholangiography (ERC) and hepatobiliary scintigraphy (HBS), using 99mTc Mebrofenin, to detect early biliary complications following OLT.

METHODS

One hundred consecutive patients who had OLT with a biliary duct-to-duct anastomosis were studied. Of these, 67 had both ERC and HBS performed within 30 days of OLT. Sensitivity, specificity and diagnostic accuracy of HBS in identifying biliary leak or stricture was calculated.

RESULTS

Of the 67 cholangiographies performed 45 were normal. In 22 patients there was radiological evidence of a leak (n = 14) or stricture (n = 8) which required further intervention in nine and four patients respectively. The sensitivity and specificity of scintigraphy for the detection of biliary leak after transplantation was 50 and 79 per cent and for biliary stricture 62 and 64 per cent respectively. No patient with normal scintigraphy required biliary intervention. Only six of 14 patients with biliary leaks and two of 20 with strictures suggested by scintigraphy required intervention. If both ERC and HBS reported leak or stricture, the intervention rate was considerably higher at five of seven leaks and two of five strictures.

CONCLUSION

This study suggests that scintigraphy is a useful screening test for biliary complications after OLT, ERC is only necessary if HBS is abnormal.

Fatal acute fulminant liver failure due to clozapine: a case report and review of clozapine-induced hepatotoxicity

Clozapine-induced hepatotoxicity is not well known and is usually of no clinical significance. This report describes fatal acute fulminant liver failure caused by clozapine in a 39-year-old man with chronic paranoid schizophrenia. The hepatotoxicity of clozapine is reviewed. Asymptomatic elevation of transaminase levels is observed most commonly, affecting between 30% and 50% of patients. Icteric hepatitis is uncommon, noted in 84 of 136,000 patients (0.06%). Fatal acute fulminant hepatitis has been documented in 2 patients (0.001%). The mechanism of clozapine hepatotoxicity is unknown. Although serious toxicity is rare, prescribers of clozapine should be aware of the hepatotoxic potential.

Antibiotic prophylaxis in gastrointestinal endoscopy: a report by a Working Party for the British Society of Gastroenterology Endoscopy Committee

Antibiotic prophylaxis is recommended for endoscopic procedures if the patient is at high risk of endocarditis or of symptomatic bacteraemia as a consequence of immunosuppression or neutropenia. In most circumstances parenteral amoxycillin and gentamicin are recommended. The addition of parenteral metronidazole is recommended in patients with neutropenia. Vancomycin or teicoplanin are recommended in patients allergic to penicillin. Antibiotic prophylaxis is recommended for all patients undergoing ERCP with evidence of biliary stasis or pancreatic pseudocyst. Oral ciprofloxacin or parenteral gentamicin (or parenteral quinolone, cephalosporin or ureidopenicillin) are recommended for ERCP.

Establishment of reference pressure of transcutaneous oxygen for the comparative evaluation of problem wounds

Seventy-two healthy males and females serially breathed air and 100% O2 at 1.0 atm abs (1.01 bar; AIR and O2, respectively), then 100% O2 at 2.36 atm abs (2.39 bar, HBO) to establish reference values for chest (CH), leg (LG), and foot (FT) PtcO2. Subjects sequentially a) rested supine with legs extended (baseline); b) elevated their monitored leg; c) returned to supine/extended position; d) assumed a seated, both legs dependent posture; and e) returned to supine/extended position. LG and FT PtcO2 decreased during leg elevation and increased when both legs were dependent during AIR, O2, and HBO (P < 0.0001, respectively). LG PtcO2 of females exceeded that for males in all conditions (P < 0.05 to P < 0.0001). Baseline CH PtcO2 also was greater than LG PtcO2 for all subjects in all conditions (P < 0.01 to P < 0.0001) and greater than FT PtcO2 for all conditions (P < 0.01 to P < 0.0001) except AIR. We conclude that: a) position and hyperoxygenation of an extremity significantly affect PtcO2; b) PtcO2 does not follow a decreasing CH to FT gradient in all conditions; c) a gender difference exists for LG PtcO2; and d) PtcO2 reference data are established for the comparative evaluation and clinical management of problem wounds.

MRI and nonverbal cognitive deficits in children with neurofibromatosis 1

Magnetic resonance imaging brain scans and neuropsychological assessments of 17 children who met the NIH consensus diagnostic criteria for neurofibromatosis Type 1 were carried out in order to determine if there is a relationship between presence of high intensity signal abnormalities on MRI scans and nonverbal cognitive deficits. Cranial MRI scans in 10 patients (58.8%) demonstrated high intensity signal abnormalities, most frequently in the cerebral peduncles. Fifteen patients had nonverbal cognitive deficits (88.2%), including difficulty judging the orientation of lines, matching complex visual stimulus configurations, recalling pictures of faces, as well as copying and drawing from memory a complex geometric figure. There was not a significant association between nonverbal neuropsychological deficits and presence of high intensity signal abnormalities on MRI scans, possibly because the location of these hyperintense abnormalities was typically below the level of the basal ganglia. These findings suggest that the high intensity signal lesions seen on the MRI scans of children with neurofibromatosis Type 1 do not predict or explain their nonverbal cognitive deficits.

Use of transcutaneous pressure of oxygen in the evaluation of edematous wounds

Transcutaneous pressure of oxygen (Ptco2) was measured in edematous wounds before and after a regimen of hyperbaric oxygen (HBO2) therapy, in patients breathing normobaric air (AIR), 100% normobaric oxygen (O2), and 100% O2 at 239 kPa (2.36 atm abs; HBO). Wounds also were scored for severity, including three ratings for periwound edema. Only during AIR was pre Ptc O2 of markedly edematous wounds significantly lower than that of moderately edematous and non-edematous wounds (P < 0.001). After HBO2 therapy, wound severity score and periwound edema rating decreased significantly (P < 0.001), and periwound edema ratings could no longer be distinguished by PtcO2. Although pre periwound PtcO2 measured during both O2 and HBO evaluations was significantly greater than that measured during AIR (P < 0.0001) and was positively correlated with subsequent change in wound severity (P < 0.05), regression analyses failed to yield a significant prediction equation. The authors conclude: a) dramatically marked increases in PtcO2 of normally hypoxic (< 30 Torr O2) edematous wounds during O2 and HBO challenges demonstrate that periwound edema is an O2 diffusion barrier during normal conditions; b) HBO2 therapy significantly reduces periwound edema in markedly edematous wounds; c) despite significant correlations between pre-therapy periwound PtcO2 measured during O2 and HBO challenges and changes in wound severity, single PtcO2 measurements are not predictive of changes in periwound edema or overall wound severity.

Families are content to discontinue antiepileptic drugs at different risks than their physicians

PURPOSE

To define the risk of seizure recurrence (RSR) that families and physicians would accept before discontinuing antiepileptic drugs (AEDs) for children with controlled epilepsy.

METHODS

A questionnaire was completed by families of 76 children with epilepsy > or = 3 months seizure-free and by their attending epilepsy specialist (n = 4).

RESULTS

Forty-two percent of families were unwilling to discontinue AEDs with an RSR of 25%. In contrast, 20% were willing to accept a > 75% RSR. Several factors differentiated the risk acceptable to families: previous seizure frequency (risk adverse with intermediate frequency), multiple seizure types (risk taking), grade or grades repeated in school (risk adverse), and the family's strategy of playing lotteries. Although families and physicians were prepared to accept similar median RSR (35 and 40%, respectively), individual answers did not correlate (r2 = -0.07). Physicians were unable to predict the families response (r2 = 0.09).

CONCLUSIONS

Our current practice is to discontinue AEDs after 2 years of seizure-free results in seizure recurrence of 30-40%. This risk may seem excessive to more than half of families, whereas other families will risk stopping AEDs at higher risks of recurrence. Physicians are poor judges of the degree of risk that is acceptable to a particular family, which may account in part for the anxiety manifested by families at AED discontinuation.

Discontinuation of anticonvulsant therapy in children free of seizures for 1 year: a prospective study

We studied 97 children who were weaned from antiepileptic drug therapy 1 year after their last seizure. Medication was withdrawn over 4 to 8 weeks, and patients were followed for 12 to 57 months (32.4 +/- 13.1; mean +/- SD) or until seizure recurrence. The overall probability of remaining seizure free was 78% at 3 months, 71% at 6 months, 66% at 12 months, and 61% at 24 months (95% CI, 51, 71), similar to studies that have required longer treatment periods. Factors retained in multivariate analysis were female sex, age at seizure onset over 120 months of age, seizure type, and clinical evidence of neurologic abnormalities. Using these risk factors, a simple method of predicting the 24-month recurrence risk was possible.