A215 MDR3 DEFICIENCY MIMICKING WILSON DISEASE

Background

The chronic phenotype of ALF includes a broad differential diagnosis. Class III multi-drug resistance P-glycoprotein 3 (MDR3) deficiency, also referred to as progressive familial intrahepatic cholestasis type 3, is an autosomal recessive genetic disorder. It is caused by a defect on the ABCB4 gene located on chromosome 7, which encodes MDR3. MDR3 is responsible for transporting phosphatidylcholine across the canalicular membrane, thereby allowing it to be incorporated into bile micelles. MDR3 deficiency results in increased levels of free bile acids and detergent bile. Progressive cholangiopathy ensues from this detergent bile and indirectly leads to cholestasis and liver failure in severe cases. Significantly increased urinary and hepatic copper (Cu), which are hallmarks of Wilson disease, have also been reported in patients with acute hepatitis and cholestasis including patients with MDR3 deficiency

Aims

We report a case of a girl who presented with a chronic phenotype of PALF, who had multiple features of Wilson disease and so was treated as such until genetic analysis confirmed MDR3 deficiency

Methods

Results

A 6 year old girl presented to the ED with a 1mth history of epistaxis and a 1wk history of abdominal pain and distension, facial edema, pallor and fever. Her family history was significant for parental consanguinity and maternal itch during pregnancy. On examination she had clubbing, scleral icterus and a distended abdomen with hepatosplenomegaly. Her bloodwork showed bicytopenia (HGB 53 & Plts 63) along with liver dysfunction (INR 2.9, albumin 25, conjugated bilirubin 9) and raised liver enzymes (transaminases & GGT >10xULN). Her total serum bile acids were raised at 134. An US showed hepatosplenomegaly with multiple hyperechoic nodules and perisplenic varices. She was extensively worked up for malignancy, autoimmune and metabolic disease. Serum ceruloplasmin was reduced, ophthalmology examination showed no KF rings and her 24hr urinary Cu was 10xULN. Liver Cu quantification was markedly raised at 40xULN. Liver biopsy showed cirrhosis with fibrosis related minimal non-specific portal and septal inflammation. Additionally, complete loss of canalicular staining on immunohistochemistry for MDR3 protein was noted, suggestive of MDR3 deficiency. Based on the Cu levels, a provisional diagnosis of Wilson disease was made and Cu chelation therapy was commenced pending genetic testing. A cholestatic gene panel subsequently showed homozygous pathogenic variant for the ABCB4 gene. Trientine was stopped and she was commenced on ursodeoxycholic acid. Though biochemically she remains largely unchanged, she is clinically stable whilst awaiting a liver transplant

Conclusions

This case highlights the diagnostic difficulties associated with Cu test result interpretation in patients with chronic cholestatic liver disease and urges a thorough consideration of alternative diagnoses of PALF

Funding Agencies

None

A110 DGAT1 MUTATION OF LIPID TRAFFICKING ASSOCIATED WITH A RARE CASE OF CONGENITAL DIARRHEA

Background

Congenital diarrheas and enteropathies (CODEs) are rare and cause severe chronic diarrhea in children under 2 years of age.1 Current genomic research has identified several monogenic defects resulting in epithelial disorders of nutrient and electrolyte transport, enzymes function, metabolism and trafficking.

Aims

To discuss a rare case of congential diarrhea.

Methods

Case Report.

Results

A 10-month-old Ashkenazi Jewish boy was referred to Pediatric Gastroenterology for loose stools and failure to thrive. Born at 27 weeks, he was a NICU inpatient for his first 3 months of life. Explosive loose stools were first noticed after discharge and treated as cow’s milk protein allergy. At aged 10 months he was admitted to his local hospital with irritability, abdominal distension, foul smelling loose stools and developmental delay. Despite an intake of 130kcal/kg/day he failed to gain weight (weight and length < 3rd centile). His abdomen was distended but there was no organomegaly on examination.

On transfer to Sick Kids he underwent extensive work up with low albumin 24 g/L but normal CBC, amylase, lipase and IgA and

anti-TTG negative. The lipid profile showed hypertriglyceridemia 2.98 mmol/L (normal <0.85), low HDL 0.81 mmol/L but normal total cholesterol. Low apoliprotein A1 0.79 g/L (0.92 - 1.96), low apoliprotein B 0.54 g (0.59 - 1.46) and vitamin E deficiency 9.6 umol/L (14.5 - 33.0). Normal fecal elastase (> 500 ug/g stool). Upper GI endoscopy showed duodenal villi blunting with non-specific chronic inactive duodenitis on histopathology.

Due to ongoing poor weight gain he commenced TPN. A repeat endoscopy four weeks after admission revealed patchy villous blunting, crypt hyperplasia and enterocyte vacuolization. However, ultrastructural electron microscopy examination showed normal enterocyte brush border with well-formed microvilli with no inclusions or vesicular bodies. With a differential diagnosis of chylomicron retention disorder, abetalipoproteinemia or hypolipoproteinemia he was commenced on a low-fat diet with MCT feeds. A 72-hour fecal fat collection on this diet was within normal range 5.4 mmol/day (2–7).

One year later his weight is now on 3rd centile and his albumin levels have normalized. However, triglycerides remain elevated. Whole exome sequencing identified two pathogenic variants in the DGAT1 gene; c.629_631delCCT, pSer210del and c751 + 2T>C, IVSB+2T>C.

Conclusions

Diacylglycerol acyltransferase (DGAT)1 catalyzes triglyceride biosynthesis.2 Loss of function DGAT1 gene mutations are described in several cases studies3,4 characterized by electrolyte transport–related diarrhea, protein-losing enteropathy and growth failure. Our cases adds to the understanding of the phenotypic and histological spectrum of DGAT1 mutations. Management strategies currently focus on growth with dietary lipid restriction, while substituting fat-soluble vitamins and essential fatty acids.

Funding Agencies

CAG

DNAAF1 links heart laterality with the AAA+ ATPase RUVBL1 and ciliary intraflagellar transport

DNAAF1 (LRRC50) is a cytoplasmic protein required for dynein heavy chain assembly and cilia motility, and DNAAF1 mutations cause primary ciliary dyskinesia (PCD; MIM 613193). We describe four families with DNAAF1 mutations and complex congenital heart disease (CHD). In three families, all affected individuals have typical PCD phenotypes. However, an additional family demonstrates isolated CHD (heterotaxy) in two affected siblings, but no clinical evidence of PCD. We identified a homozygous DNAAF1 missense mutation, p.Leu191Phe, as causative for heterotaxy in this family. Genetic complementation in dnaaf1-null zebrafish embryos demonstrated the rescue of normal heart looping with wild-type human DNAAF1, but not the p.Leu191Phe variant, supporting the conserved pathogenicity of this DNAAF1 missense mutation. This observation points to a phenotypic continuum between CHD and PCD, providing new insights into the pathogenesis of isolated CHD. In further investigations of the function of DNAAF1 in dynein arm assembly, we identified interactions with members of a putative dynein arm assembly complex. These include the ciliary intraflagellar transport protein IFT88 and the AAA+ (ATPases Associated with various cellular Activities) family proteins RUVBL1 (Pontin) and RUVBL2 (Reptin). Co-localization studies support these findings, with the loss of RUVBL1 perturbing the co-localization of DNAAF1 with IFT88. We show that RUVBL1 orthologues have an asymmetric left-sided distribution at both the mouse embryonic node and the Kupffer's vesicle in zebrafish embryos, with the latter asymmetry dependent on DNAAF1. These results suggest that DNAAF1-RUVBL1 biochemical and genetic interactions have a novel functional role in symmetry breaking and cardiac development.

The Doctor Can See You Now: A Key Stakeholder Study Into The Acceptability Of Ambulance Based Telemedicine

Using telecommunications technology it would be possible to link a patient and paramedic to a Doctor in the Emergency Department (ED) at the point of first patient contact. A questionnaire-based study on telemedicine in the pre-hospital environment involving patients, paramedics, doctors and nurses in the ED, was performed to assess if they would want and accept telemedicine in pre-hospital emergency care. When asked 98.5% (55) of patients, 89% (11) of doctors, 76% (14) of nurses and 91% (42) of ambulance personnel saw the potential of an audio-visual link from the pre-hospital environment to the ED. The potential benefits were felt to be in diagnosis of time-dependent illnesses, time management, increased hospital preparedness for incoming patients and increased triage efficiency. Stakeholder enthusiasm for pre-hospital telemedicine must be met with the technological requirements to provide such a service. As noted by one patient a pre-hospital audio-visual link to the ED could be “potentially a life saving service”.

Developing a risk-based trading scheme for cattle in England: farmer perspectives on managing trading risk for bovine tuberculosis

This paper examines farmer attitudes towards the development of a voluntary risk-based trading scheme for cattle in England as a risk mitigation measure for bovine tuberculosis (bTB). The research reported here was commissioned to gather evidence on the type of scheme that would have a good chance of success in improving the information farmers receive about the bTB risk of cattle they buy. Telephone interviews were conducted with a stratified random sample of 203 cattle farmers in England, splitting the interviews equally between respondents in the high-risk area and low-risk area for bTB. Supplementary interviews and focus groups with farmers were also carried out across the risk areas. Results suggest a greater enthusiasm for a risk-based trading scheme in low-risk areas compared with high-risk areas and among members of breed societies and cattle health schemes. Third-party certification of herds by private vets or the Animal and Plant Health Agency were regarded as the most credible source, with farmer self-certification being favoured by sellers, but being regarded as least credible by buyers. Understanding farmers' attitudes towards voluntary risk-based trading is important to gauge likely uptake, understand preferences for information provision and to assist in monitoring, evaluating and refining the scheme once established.

Improved Delivery through Biological Membranes. Synthesis and Antiviral Activity of a Series of Ribavirin Chemical Delivery Systems: 2′ and 3′ Derivatives

Ribavirin was chemically manipulated to provide a number of derivatives in which a 1,4-dihydrotrigonellinate species was attached to either the 2′ or 3′-position. In addition, a variety of other modifications was used to augment the lipophilicity and stability of the ribavirin redox systems. Prepared compounds were tested in a murine model of viral encephalitis. Intravenous administration of an isomeric pair of derivatives (1-[3′-O-(N-methyl-3-carbonyl-1,4-dihydropyridine)-2′-O-benzoyl-β-D-ribofuranosyl]-1,2,4-triazole-3-carboxamide/1-[2′-O-(N-methyl-3-carbonyl-1,4-dihydropyridine)-3′-O-benzoyl-β-D-ribofuranosyl]-1,2,4-triazole-3-carboxamide) resulted in 43% survival compared with 0% for vehicle treatment and resulted in a decrease in brain viral titres by 10-fold.

Mutual information as a measure of image quality for 3D dynamic lung imaging with EIT

We report on a pilot study of dynamic lung electrical impedance tomography (EIT) at the University of Manchester. Low-noise EIT data at 100 frames per second were obtained from healthy male subjects during controlled breathing, followed by magnetic resonance imaging (MRI) subsequently used for spatial validation of the EIT reconstruction. The torso surface in the MR image and electrode positions obtained using MRI fiducial markers informed the construction of a 3D finite element model extruded along the caudal-distal axis of the subject. Small changes in the boundary that occur during respiration were accounted for by incorporating the sensitivity with respect to boundary shape into a robust temporal difference reconstruction algorithm. EIT and MRI images were co-registered using the open source medical imaging software, 3D Slicer. A quantitative comparison of quality of different EIT reconstructions was achieved through calculation of the mutual information with a lung-segmented MR image. EIT reconstructions using a linear shape correction algorithm reduced boundary image artefacts, yielding better contrast of the lungs, and had 10% greater mutual information compared with a standard linear EIT reconstruction.

Femtosecond luminescence spectroscopy of core states in silicon nanocrystals

We present a study of ultrafast carrier transfer from highly luminescent states inside the core of silicon nanocrystal (due to quasidirect transitions) to states on the nanocrystal-matrix interface. This transfer leads to a sub-picosecond luminescence decay, which is followed by a slower decay component induced by carrier relaxation to lower interface states. We investigate the luminescence dynamics for two different surface passivation types and we propose a general model describing spectral dependence of ultrafast carrier dynamics. Our results stress the crucial role of the energy distribution of the interface states on surface-related quenching of quasidirect luminescence in silicon nanocrystals. We discuss how to avoid this quenching in order to bring the attractive properties of the quasidirect recombination closer to exploitation.

Accelerated dobutamine stress testing: safety and feasibility in patients with known or suspected coronary artery disease

BACKGROUND

Dobutamine pharmodynamics require approximately 10 min to reach steady state. Despite this, standard dobutamine stress echo typically uses 3-min stages of advancing dobutamine doses because of safety concerns.

HYPOTHESIS

In patients with a high pretest probability of coronary artery disease (CAD), a continuous infusion of high-dose dobutamine is a feasible and safe method for performing a dobutamine stress test.

METHODS

Forty-seven consecutive patients (mean age 64 +/- 11 years) with 3.0 +/- 1.4 cardiac risk factors underwent dobutamine stress testing utilizing a single, high-dose (40 mcg/kg/min), continuous dobutamine infusion. The 40 mcg/kg/min infusion was continued for up to 10 min or until a test endpoint had been reached. If a test endpoint was not achieved, atropine (up to 1.0 mg) was added.

RESULTS

Heart rate rose from 71 +/- 12 to 137 +/- 18 beats/min at peak (p<0.0001) with a concomitant change in systolic blood pressure (143 +/- 35 vs. 167 +/- 38 mmHg; p = 0.001) but no change in diastolic blood pressure (74 +/- 19 vs. 75 +/- 18 mmHg; p = NS). Target heart rate was achieved in 20 of 47 (43%) patients with accelerated dobutamine alone and in 34 of 47 (72%) with the addition of atropine. An average of 11.6 +/- 3.7 min was required to obtain target heart rate. Subjective sensations from the dobutamine occurred in 49% of patients (palpitations 21%, nausea 6%, chest pain 6%, headache 6%, dizziness 13%), mild arrhythmia in 48% of patients (ventricular premature beats 38%, supraventricular tachycardia 10%), and one patient had nonsustained ventricular tachycardia.

CONCLUSION

A single, high-dose (40 mcg/kg/min) dobutamine-atropine protocol provides an efficient means of performing dobutamine stress echocardiography with a similar symptom profile as conventional dobutamine infusion protocols in patients with a high pretest probability of CAD. Randomized, controlled studies will be necessary to assess the sensitivity and specificity of this accelerated dobutamine echo protocol.

Emergency intubation for acutely ill and injured patients

BACKGROUND

Emergency intubation has been widely advocated as a life saving procedure in severe acute illness and injury associated with real or potential compromises to the patient's airway and ventilation. However, some initial data have suggested a lack of observed benefit.

OBJECTIVES

To determine in acutely ill and injured patients who have real or anticipated problems in maintaining an adequate airway whether emergency endotracheal intubation, as opposed to other airway management techniques, improves the outcome in terms of survival, degree of disability at discharge or length of stay and complications occurring in hospital.

SEARCH STRATEGY

We searched the Cochrane Injuries Group Specialised Register (December 2006), Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2006, Issue 4), MEDLINE (1950 to November 2006), EMBASE (1980 to week 50, December 2006), National Research Register (Issue 4, 2006), CINAHL (1980 to December 2006), BIDS (to December 2006) and ICNARC (to December 2006). We also examined reference lists of articles for relevant material and contacted experts in the field. Non-English language publications were searched for and examined.

SELECTION CRITERIA

All randomised (RCTs) or controlled clinical trials involving the emergency use of endotracheal intubation in the injured or acutely ill patient were examined.

DATA COLLECTION AND ANALYSIS

The full texts of 452 studies were reviewed independently by two authors using a standard form. Where the review authors felt a study may be relevant for inclusion in the final review or disagreed, the authors examined the study and a collective decision was made regarding its inclusion or exclusion from the review. The results were not combined in a meta-analysis due to the heterogeneity of patients, practitioners and alternatives to intubation that were used.

MAIN RESULTS

We identified three eligible RCTs carried out in urban environments. Two trials involved adults with non-traumatic out-of-hospital cardiac arrest. One of these trials found a non-significant survival disadvantage in patients randomised to receive a physician-operated intubation versus a combi-tube (RR 0.44, 95% CI 0.09 to 1.99). The second trial detected a non-significant survival disadvantage in patients randomised to paramedic intubation versus an oesophageal gastric airway (RR 0.86, 95% CI 0.39 to 1.90). The third included study was a trial of children requiring airway intervention in the prehospital environment. The results indicated no difference in survival (OR 0.82, 95% CI 0.61 to 1.11) or neurologic outcome (OR 0.87, 95% CI 0.62 to 1.22) between paramedic intubation versus bag-valve-mask ventilation and later hospital intubation by emergency physicians; however, only 42% of the children randomised to paramedic endotracheal intubation actually received it.

AUTHORS' CONCLUSIONS

The efficacy of emergency intubation as currently practised has not been rigorously studied. The skill level of the operator may be key in determining efficacy. In non-traumatic cardiac arrest, it is unlikely that intubation carries the same life saving benefit as early defibrillation and bystander cardiopulmonary resuscitation (CPR). In trauma and paediatric patients, the current evidence base provides no imperative to extend the practice of prehospital intubation in urban systems. It would be ethical and pertinent to initiate a large, high quality randomised trial comparing the efficacy of competently practised emergency intubation with basic bag-valve-mask manoeuvres (BVM) in urban adult out-of-hospital non-traumatic cardiac arrest.

Efficacy and toxicity of dose-adjusted EPOCH-rituximab in adults with newly diagnosed Burkitt lymphoma

8035

Background: Burkitt Lymphoma (BL) is a rare and highly aggressive lymphoma, characterized by a high tumor proliferation rate. While the standard therapy of BL is highly effective, it involves intensive, multi-agent chemotherapy that is associated with considerable treatment-related toxicity and mortality, especially in older patients. We hypothesized that the regimen DA-EPOCH may be effective in BL, based on the observation that it overcomes the adverse effect of high proliferation in diffuse large B-cell lymphoma. Methods: We investigated DA-EPOCH-rituximab (R) in untreated BL in an attempt to maintain the high cure rates of standard therapy with minimal treatment related toxicity. Eligible patients had a diagnosis of untreated BL and could be HIV negative or positive with HIV negative patients (n=13) receiving 6 cycles of DA-EPOCH-R as previously described (Blood 99: 2685, 2002) and HIV positive (n=6) patients receiving 3–6 cycles of DA- EPOCH-R for 1 cycle beyond CR for a minimum of 3 cycles. All patients received intrathecal methotrexate prophylaxis and outpatient therapy where possible. Results: The characteristics of 19 enrolled patients are: median age (range) 29 (18–66) and ECOG PS 1(1–3); stage III/IV 10 (53%); LDH > N 11 (61%); male sex 15 (79%); extranodal sites 13 (68%) and ileocecal disease 13 (68%). No patients so far had CNS involvement at diagnosis. Response is CR/CRu in 100% of patients with one patient receiving consolidative radiotherapy to a site of residual disease. OS and PFS are both 100% and EFS 93.3% at a median potential follow-up time of 29 months. Toxicities were fever/neutropenia in 16%, grade 4 neutropenia in 47% and grade 3/4 thrombocytopenia in 22% of cycles. There was one case of tumor lysis syndrome and no treatment related deaths. Conclusions: DA-EPOCH-R is highly effective in BL. It appears to be associated with much lower toxicity compared to standard high-dose regimens and may significantly advance the therapeutic index of BL treatment. Accrual continues.

No significant financial relationships to disclose.

A prospective mini health impact assessment of the 'Towards 2010' programme in Sandwell and West Birmingham in the West Midlands

OBJECTIVES

To conduct a health impact assessment (HIA) of the four 'Towards 2010' programme options under consideration. This is an innovative and visionary programme involving a 750 million pound capital investment to deliver modern and flexible healthcare services across Sandwell and West Birmingham in the West Midlands, UK. The HIA aimed to inform the Board which of the four options would be most beneficial for the local population.

STUDY DESIGN

A prospective mini HIA.

METHODS

The study involved a desktop exercise using a combination of the Merseyside and West Midlands Directors of Public Health guidelines for conducting HIAs. Ten broad determinants of health including employment and economy, education, transport, housing, visual amenity (environment), access to services, crime, lifestyle, pollution, and family and social cohesion were selected. For each determinant potential positive and negative impacts were identified using readily available local information and professional knowledge.

RESULTS

Overall over 600 positive and negative impacts were predicted across the four options. These were summarized into 90 positive and 84 negative impacts for each of the ten broad determinants of health. The findings suggest that two out of the four options seem to offer maximum opportunity for improving the health and wellbeing of the local population and for linking into the wider regeneration initiatives within the programme area.

DISCUSSION

Besides the obvious benefits that one would expect from brand new modern healthcare facilities, a wide range of other impacts were identified. This raised a level of awareness amongst the decision makers of the range of impacts that would need to be maximized or minimized to improve the health and wellbeing of the local population.

Role of the central region of NifL in conformational switches that regulate nitrogen fixation

The NifL regulatory protein is an anti-activator that tightly regulates transcription of genes required for nitrogen fixation in Azotobacter vinelandii by controlling the activity of its partner protein NifA through the formation of a protein-protein complex. NifL modulates the activity of NifA in response to the redox, carbon and nitrogen status to ensure that nitrogen fixation occurs only under physiological conditions that are appropriate for nitrogenase activity. The domain architecture of NifL is similar to that of some histidine protein kinases, with two N-terminal PAS (PER, ARNT, SIM) domains, one of which contains an FAD cofactor that senses the redox status, and a C-terminal domain containing conserved residues that constitutes the nucleotide-binding domain of the GHKL (gyrase, Hsp90, histidine kinase, MutL) superfamily of ATPases. We have evidence that the central region of NifL, which is located between the PAS domains and the C-terminal GHKL nucleotide-binding domain, plays a crucial role in the propagation of signals perceived in response to the redox and fixed nitrogen status and that this region participates in conformational changes that switch NifL between active and inactive states. We have identified a critical arginine residue in the central region of NifL that participates in the conformational switch that activates NifL. Mutations in the central region of NifL that disable the redox-sensing function of NifL but leave the protein competent to respond to the nitrogen signal conveyed by the signal transduction protein GlnK have also been isolated. Our results suggest that the topological relationship between the central region and the GHKL domain may alter as a consequence of conformational changes induced in response to signal perception.

Replacement of routine liver biopsy by procollagen III aminopeptide for monitoring patients with psoriasis receiving long-term methotrexate: a multicentre audit and health economic analysis

BACKGROUND

Patients receiving long-term methotrexate for psoriasis are at risk of developing hepatic fibrosis. Repeated liver biopsy has long been regarded as the only reliable method of detecting this and it is still recommended by the American Academy of Dermatology (AAD). More recently, monitoring by serum procollagen III aminopeptide (PIIINP) measurement (Orion Diagnostica, Espoo, Finland) has been advocated as a means of significantly reducing the need for liver biopsy.

OBJECTIVES

To assess the validity of guidelines developed in Manchester for the use of PIIINP to monitor patients with psoriasis receiving long-term methotrexate; to assess the anticipated benefits to patients of introducing this change in practice, including reduction in requirement for liver biopsy; and to determine the impact of its introduction on healthcare costs.

METHODS

A multicentre audit was conducted over a 24-month period to compare the healthcare costs and outcomes of two intervention groups from centres where serial PIIINP measurement was employed with those of two control groups from centres in which AAD guidelines were followed.

RESULTS

A sevenfold reduction in the need for liver biopsy was observed in the two intervention groups (n = 166; 0.04 and 0.02 biopsies/patient/year, respectively) compared with the two control groups (n = 87; 0.26 and 0.30 biopsies/patient/year, respectively). Abnormalities of sufficient severity to influence management were identified in one in five patients biopsied in the main intervention group compared with one in 16 in the control groups. The overwhelming majority of patients surveyed expressed a preference for being monitored by methods that would minimize the need for liver biopsy. The adoption of PIIINP for monitoring would result in significant cost savings.

CONCLUSIONS

This audit has shown that patients managed by the Manchester protocol using serial PIIINP measurement and selective liver biopsy were not disadvantaged in comparison with those managed according to AAD guidelines; they were subjected to sevenfold fewer liver biopsies without evidence that important liver toxicity was missed in the process. If PIIINP monitoring were widely adopted, methotrexate would become a more acceptable option for many patients who are dissuaded from considering it because of the threat of repeated liver biopsy; it would also result in significant savings to the healthcare budget.

Nitrogen fixation: key genetic regulatory mechanisms

The necessity to respond to the level of fixed nitrogen and external oxygen concentrations and to provide sufficient energy for nitrogen fixation imposes common regulatory principles amongst diazotrophs. The NifL-NifA system in Azotobacter vinelandii integrates the signals of redox, fixed-nitrogen and carbon status to regulate nif transcription. Multidomain signalling interactions between NifL and NifA are modulated by redox changes, ligand binding and interaction with the signal-transduction protein GlnK. Under adverse redox conditions (excess oxygen) or when fixed nitrogen is in excess, NifL forms a complex with NifA in which transcriptional activation is prevented. Oxidized NifL forms a binary complex with NifA to inhibit NifA activity. When fixed nitrogen is in excess, the non-covalently modified form of GlnK interacts with NifL to promote the formation of a GlnK-NifL-NifA ternary complex. When the cell re-encounters favourable conditions for nitrogen fixation, it is necessary to deactivate the signals to ensure that the NifL-NifA complex is dissociated so that NifA is free to activate transcription. This is achieved through interactions with 2-oxoglutarate, a key metabolic signal of the carbon status, which binds to the N-terminal GAF (cGMP-specific and stimulated phosphodiesterases, Anabaena adenylate cyclases and Escherichia coli FhlA) domain of NifA.

REM sleep behavior disorder is related to striatal monoaminergic deficit in MSA

OBJECTIVE

To explore the neurochemical basis of REM sleep behavior disorder (RBD) in multiple-system atrophy (MSA).

METHODS

In 13 patients with probable MSA, nocturnal, laboratory-based polysomnography was used to rate the severity of REM atonia loss by the percentage of REM sleep with tonically increased electromyographic (EMG) activity and the percentage of REM sleep with phasic EMG bursts. PET with (+)-[11C]dihydrotetrabenazine ([11C]DTBZ) was employed to measure the density of striatal monoaminergic terminals and SPECT with (-)-5-[123I]iodobenzovesamicol ([123I]IBVM) to measure the density of 123I]IBVM.

RESULTS

Age and gender distributions were similar in patient and normal control groups. The MSA subjects showed decreased mean [11C]DTBZ binding in the striatum (p < 0.0001) and decreased [123I]IBVM binding in the thalamus (p < 0.001). Moreover, in the MSA group, striatal [11C]DTBZ binding was inversely correlated with the severity of REM atonia loss (p = 0.003). Thalamic [123I]IBVM binding, however, was not correlated to the severity of REM atonia loss.

CONCLUSION

Decreased nigrostriatal dopaminergic projections may contribute to RBD in MSA.

Obstructive sleep apnea is related to a thalamic cholinergic deficit in MSA

OBJECTIVE

To explore the neurochemical basis of obstructive sleep apnea (OSA) in multiple-system atrophy (MSA).

METHODS

In 13 patients with probable MSA, nocturnal, laboratory-based polysomnography was used to rate the severity of OSA using the apnea-hypopnea index during sleep. SPECT with (-)-5-[123I]iodobenzovesamicol ([123I]IBVM) was utilized to measure the density of thalamic cholinergic terminals, which project from the brainstem pedunculopontine and laterodorsal tegmental nuclei. PET with (+)-[11C]dihydrotetrabenazine ([11C]DTBZ) was also used to measure the density of striatal monoaminergic terminals, which project from the brainstem. Findings in the patient group were compared with data from 12 normal control subjects scanned utilizing [123I]IBVM and 15 normal control subjects utilizing [11C]DTBZ.

RESULTS

Age and gender distributions were similar in patient and control groups. The MSA subjects showed decreased [123I]IBVM binding in the thalamus (p < 0.001) and decreased mean [11C]DTBZ binding in the striatum (p < 0.0001) in comparison with the control subjects. In the MSA group, thalamic [123I]IBVM binding was inversely correlated with the severity of OSA (p = 0.011). Striatal [11C]DTBZ binding was not correlated with the severity of OSA (p = 0.19).

CONCLUSION

Decreased pontine cholinergic projections may contribute to OSA in MSA.

Shape and propagation of systemic pulsatile blood pressure during the evolution of porcine haemorrhagic shock

Background

The shape and propagation of systemic pulsatile blood pressure was evaluated during the evolution of haemorrhagic shock in pigs.

Methods

Twenty-seven Saffan anaesthetized, mechanically ventilated pigs were randomized to a control group, a haemorrhage group with no resuscitation (25 per cent blood loss over 20 min) and an identical haemorrhage group but with reinfusion of shed blood over a further 20 min. Standard invasive haemodynamic monitoring was conducted, as well as digital recordings of blood pressure (via semiconductor catheter-tipped pressure transducers) at consecutive sites from the aortic arch to the femoral artery.

Results

The data are presented as time-averaged isobaric pulsatile contour plots of wave propagation from the aortic arch to the femoral artery. The colour contours encompass relative pressure measurements from the troughs of diastole (blue) to the peaks of systole (red). Distance from aortic arch to femoral artery was 50 cm in this series and the time axis travelled from left to right and over 0·7 s for each figure. Data were obtained before and after 25% haemorrhage and again after restoration of blood volume.

Conclusion

The time-domain morphology of the pulsatile blood pressure waveform and its systemic propagation is changed during a survivable haemorrhage. Furthermore, recovery is apparent following blood volume restoration.

TNF alpha and IL-6 involvement in surgical trauma. II. In vitro cytokine production

The study aimed to correlate TNF alpha and IL-6 dynamics during surgical trauma as well as the changes which appear in the circulating monocytes' response after LPS stimulation in vitro. Three patients with major abdominal operations were chosen and serial blood samples were taken before, during and after the operation. Normal unmatched individuals were used as control group during a two hours bed resting period. Both TNF alpha and IL-6 in vitro production showed similar patterns with an initial drop and almost full recovery 24 hours after the operation. We propose a model for TNF alpha and IL-6 role in trauma induced inflammation.

Rehabilitation after total shoulder arthroplasty

Physical therapy constitutes an essential determinant of clinical outcome after total shoulder arthroplasty. We reviewed our results in 81 shoulders at a minimum of 2 years' follow-up, with specific focus on the maintenance of motion and the development of soft tissue healing problems. Our findings show that our graduated rehabilitation program allows most patients to obtain motion comparable to that possible intraoperatively with few complications. Of patients, 70% maintained their elevation, and 90% maintained external rotation. Patients with a diagnosis of rheumatoid arthritis, traumatic arthritis, and osteonecrosis were identified as being at risk for failure to regain motion and for tendon healing complications.

Role of Escherichia coli nitrogen regulatory genes in the nitrogen response of the Azotobacter vinelandii NifL-NifA complex

The redox-sensing flavoprotein NifL inhibits the activity of the nitrogen fixation (nif)-specific transcriptional activator NifA in Azotobacter vinelandii in response to molecular oxygen and fixed nitrogen. Although the mechanism whereby the A. vinelandii NifL-NifA system responds to fixed nitrogen in vivo is unknown, the glnK gene, which encodes a PII-like signal transduction protein, has been implicated in nitrogen control. However, the precise function of A. vinelandii glnK in this response is difficult to establish because of the essential nature of this gene. We have shown previously that A. vinelandii NifL is able to respond to fixed nitrogen to control NifA activity when expressed in Escherichia coli. In this study, we investigated the role of the E. coli PII-like signal transduction proteins in nitrogen control of the A. vinelandii NifL-NifA regulatory system in vivo. In contrast to recent findings with Klebsiella pneumoniae NifL, our results indicate that neither the E. coli PII nor GlnK protein is required to relieve inhibition by A. vinelandii NifL under nitrogen-limiting conditions. Moreover, disruption of both the E. coli glnB and ntrC genes resulted in a complete loss of nitrogen regulation of NifA activity by NifL. We observe that glnB ntrC and glnB glnK ntrC mutant strains accumulate high levels of intracellular 2-oxoglutarate under conditions of nitrogen excess. These findings are in accord with our recent in vitro observations (R. Little, F. Reyes-Ramirez, Y. Zhang, W. Van Heeswijk, and R. Dixon, EMBO J. 19:6041-6050, 2000) and suggest a model in which nitrogen control of the A. vinelandii NifL-NifA system is achieved through the response to the level of 2-oxoglutarate and an interaction with PII-like proteins under conditions of nitrogen excess.

Successful treatment of vancomycin-resistant Enterococcus endocarditis with oral linezolid

We report a case of vancomycin-resistant Enterococcus faecium endocarditis that failed to respond to sequential monotherapy with chloramphenicol and quinupristin/dalfopristin but was successfully treated with oral linezolid.