Antimicrobial use and appropriateness in neutropenic fever: a study of the Hospital National Antimicrobial Prescribing Survey data

BACKGROUND

Neutropenic fever (NF) is a common complication in patients receiving chemotherapy. Judicious antimicrobial use is paramount to minimize morbidity and mortality and to avoid antimicrobial-related harms.

OBJECTIVES

To use an Australian national dataset of antimicrobial prescriptions for the treatment of NF to describe antimicrobial use, prescription guideline compliance and appropriateness; and to compare these findings across different healthcare settings and patient demographics. We also aimed to identify trends and practice changes over time.

METHODS

Data were extracted from the Hospital National Antimicrobial Prescribing Survey (Hospital NAPS) database from August 2013 to May 2022. Antimicrobial prescriptions with a NF indication were analysed for antimicrobial use, guideline compliance and appropriateness according to the Hospital NAPS methodology. Demographic factors, hospital classifications and disease characteristics were compared.

RESULTS

A total of 2887 (n = 2441 adults, n = 441 paediatric) NF prescriptions from 254 health facilities were included. Piperacillin-tazobactam was the most prescribed antimicrobial. Overall, 87.4% of prescriptions were appropriate. Piperacillin-tazobactam and cefepime had the highest appropriateness though incorrect piperacillin-tazobactam dosing was observed. Lower appropriateness was identified for meropenem, vancomycin, and gentamicin prescribing particularly in the private hospital and paediatric cohorts. The most common reasons for inappropriate prescribing were spectrum too broad, incorrect dosing or frequency, and incorrect duration.

CONCLUSIONS

This study provides insights into antimicrobial prescribing practices for NF in Australia. We have identified three key areas for improvement: piperacillin-tazobactam dosing, paediatric NF prescribing and private hospital NF prescribing. Findings from this study will inform the updated Australian and New Zealand consensus guidelines for the management of neutropenic fever in patients with cancer.

Evaluating the cost-effectiveness of [18F]FDG-PET/CT for investigation of persistent or recurrent neutropenic fever in high-risk haematology patients

BACKGROUND

A recent randomised trial demonstrated [18F]fluorodeoxyglucose positron-emission tomography in combination with low-dose CT (FDG-PET/CT), compared to standard of care computed tomography (CT) imaging, positively impacted antimicrobial management and outcomes of acute leukaemia and haematopoietic stem cell transplant recipients with persistent and recurrent neutropenic fever. We conducted an economic evaluation from a healthcare perspective alongside the clinical trial.

METHODS

Unit costs in Australian dollars were applied to all resources used (antimicrobials, diagnostic tests, ICU and hospital bed days). Effectiveness was measured as number of patients with antimicrobial rationalisation, 6-month mortality and quality-adjusted life years (QALYs) derived from patient-reported trial-based health-related quality-of-life. Generalised linear models were used to analyse costs and outcomes. Incremental cost-effectiveness ratios (ICERs) for all outcomes and net monetary benefit (NMB) for QALYs were calculated. We performed bootstrapping with 1000 replications using the recycled predictions method.

RESULTS

The adjusted healthcare costs were lower for FDG-PET/CT (mean $49,563; 95%CI 36,867, 65,133) compared to CT (mean $57,574; 95% CI 44,837, 73,347). The difference in QALYs between the two groups was small (0.001; 95% CI -0.001, 0.004). When simulated 1000 times, FDG-PET/CT was the dominant strategy as it was cheaper with better outcomes than the standard CT group in 74% of simulations. The estimated NMBs at willingness-to-pay thresholds of $50,000 and $100,000 per QALY were positive, thus FDG-PET/CT remained cost-effective at these thresholds.

CONCLUSIONS

FDG-PET/CT is cost effective when compared to CT for investigation of persistent/recurrent neutropenic fever in high-risk patients, providing further support for incorporation of FDG-PET/CT into clinical guidelines and funding.

TRIAL REGISTRATION

This trial is registered with ClinicalTrials.gov, NCT03429387.

Outbreaks of Fungal Infections in Hospitals: Epidemiology, Detection, and Management

Nosocomial clusters of fungal infections, whilst uncommon, cannot be predicted and are associated with significant morbidity and mortality. Here, we review reports of nosocomial outbreaks of invasive fungal disease to glean insight into their epidemiology, risks for infection, methods employed in outbreak detection including genomic testing to confirm the outbreak, and approaches to clinical and infection control management. Both yeasts and filamentous fungi cause outbreaks, with each having general and specific risks. The early detection and confirmation of the outbreak are essential for diagnosis, treatment of affected patients, and termination of the outbreak. Environmental sampling, including the air in mould outbreaks, for the pathogen may be indicated. The genetic analysis of epidemiologically linked isolates is strongly recommended through a sufficiently discriminatory approach such as whole genome sequencing or a method that is acceptably discriminatory for that pathogen. An analysis of both linked isolates and epidemiologically unrelated strains is required to enable genetic similarity comparisons. The management of the outbreak encompasses input from a multi-disciplinary team with epidemiological investigation and infection control measures, including screening for additional cases, patient cohorting, and strict hygiene and cleaning procedures. Automated methods for fungal infection surveillance would greatly aid earlier outbreak detection and should be a focus of research.

The Who, What, When, and Where of Inpatient Direct Oral Penicillin Challenge-Implications for Health Services Implementation

Inpatient direct oral challenge programs are increasingly deployed as part of antimicrobial stewardship initiatives to reduce the burden and impacts of penicillin allergy labels on antibiotic prescribing. Using data from a prospective, multicenter cohort inpatient penicillin allergy program, we identify the key targets for delabeling to aid health service implementation.

Validation of the Antifungal National Antimicrobial Prescribing Survey (AF-NAPS) quality assessment tool

BACKGROUND

The Antifungal National Antimicrobial Prescribing Survey (AF-NAPS) was developed to undertake streamlined quality audits of antifungal prescribing. The validity and reliability of such tools is not characterized.

OBJECTIVES

To assess the validity and reliability of the AF-NAPS quality assessment tool.

METHODS

Case vignettes describing antifungal prescribing were prepared. A steering group was assembled to determine gold-standard classifications for appropriateness and guideline compliance. Infectious diseases physicians, antimicrobial stewardship (AMS) and specialist pharmacists undertook a survey to classify appropriateness and guideline compliance of prescriptions utilizing the AF-NAPS tool. Validity was measured as accuracy, sensitivity and specificity compared with gold standard. Inter-rater reliability was measured using Fleiss' kappa statistics. Assessors' responses and comments were thematically analysed to determine reasons for incorrect classification.

RESULTS

Twenty-eight clinicians assessed 59 antifungal prescriptions. Overall accuracy of appropriateness assessment was 77.0% (sensitivity 85.3%, specificity 68.0%). Highest accuracy was seen amongst specialist (81%) and AMS pharmacists (79%). Prescriptions with lowest accuracy were in the haematology setting (69%), use of echinocandins (73%), mould-active azoles (75%) and for prophylaxis (71%). Inter-rater reliability was fair overall (0.3906), with moderate reliability amongst specialist pharmacists (0.5304). Barriers to accurate classification were incorrect use of the appropriateness matrix, knowledge gaps and lack of guidelines for some indications.

CONCLUSIONS

The AF-NAPS is a valid tool, assisting assessors to correctly classify appropriate prescriptions more accurately than inappropriate prescriptions. Specialist and AMS pharmacists had similar performance, providing confidence that both can undertake AF-NAPS audits to a high standard. Identified reasons for incorrect classification will be targeted in the online tool and educational materials.

Establishing essential metrics for antifungal stewardship in hospitals: the results of an international Delphi survey

BACKGROUND

Guidance on assessment of the quantity and appropriateness of antifungal prescribing is required to assist hospitals to interpret data effectively and structure quality improvement programmes.

OBJECTIVES

To achieve expert consensus on a core set of antifungal stewardship (AFS) metrics and to determine their feasibility for implementation.

METHODS

A literature review was undertaken to develop a list of candidate metrics. International experts were invited to participate in sequential web-based surveys to evaluate the importance and feasibility of metrics in the area of AFS using Delphi methodology. Three surveys were completed. Consensus was predefined as ≥80% agreement on the importance of each metric.

RESULTS

Eighty-two experts consented to participate from 17 different countries. Response rate for each survey was >80%. The panel included adult and paediatric physicians, microbiologists and pharmacists with diverse content expertise. Consensus was achieved for 38 metrics considered important to routinely include in AFS programmes, and related to antifungal consumption (n = 5), quality of antifungal prescribing and management of invasive fungal infection (IFI) (n = 24), and clinical outcomes (n = 9). Twenty-one consensus metrics were considered to have moderate to high feasibility for routine collection.

CONCLUSIONS

The identified core AFS metrics will provide a framework to comprehensively assess the quantity and quality of antifungal prescribing within hospitals to develop quality improvement programmes aimed at improving IFI prevention, management and patient-centred outcomes. A standardized approach will support collaboration and benchmarking to monitor the efficacy of current prophylaxis and treatment guidelines, and will provide important feedback to guideline developers.

Epidemiology, treatment and outcomes of bloodstream infection due to vancomycin-resistant enterococci in cancer patients in a vanB endemic setting

Background

Vancomycin-resistant enterococcus (VRE) is an important cause of infection in immunocompromised populations. Few studies have described the characteristics of vanB VRE infection. We sought to describe the epidemiology, treatment and outcomes of VRE bloodstream infections (BSI) in a vanB predominant setting in malignant hematology and oncology patients.

Methods

A retrospective review was performed at two large Australian centres and spanning a 6-year period (2008–2014). Evaluable outcomes were intensive care admission (ICU) within 48 h of BSI, all-cause mortality (7 and 30 days) and length of admission.

Results

Overall, 106 BSI episodes were observed in 96 patients, predominantly Enterococcus faecium vanB (105/106, 99%). Antibiotics were administered for a median of 17 days prior to BSI, and 76/96 (79%) were neutropenic at BSI onset. Of patients screened before BSI onset, 49/72 (68%) were found to be colonised. Treatment included teicoplanin (59), linezolid (6), daptomycin (2) and sequential/multiple agents (21). Mortality at 30-days was 31%. On multivariable analysis, teicoplanin was not associated with mortality at 30 days.

Conclusions

VRE BSI in a vanB endemic setting occurred in the context of substantive prior antibiotic use and was associated with high 30-day mortality. Targeted screening identified 68% to be colonised prior to BSI. Teicoplanin therapy was not associated with poorer outcomes and warrants further study for vanB VRE BSI in cancer populations.

The QuantiFERON Monitor® assay is predictive of infection post allogeneic hematopoietic cell transplantation

INTRODUCTION

Following allogeneic hematopoietic stem cell transplantation (alloHCT), excessive immunosuppression can be complicated by infection, while inadequate immunosuppression can result in graft-vs-host disease (GVHD). An accurate method to assess overall immune status post HCT is lacking. The QuantiFERON Monitor^® (QFM) assay measures interferon gamma (IFN-γ) release from whole blood following incubation with both innate (Toll-like receptor 7, TLR7) and adaptive (CD3 antibody) stimulants and may result in a more complete assessment of the immune system.

METHODS

Whole blood samples were prospectively collected from alloHCT recipients at conditioning followed by days 10, 30, 60, 90, 120, and 180 post-transplant and assayed by the QFM test. IFN-γ levels were correlated to time post HCT and episodes of infection and GVHD.

RESULTS

Forty patients were enrolled in the study (68% male; median age 47 years; 58% matched related donors, 42% unrelated; 33% myeloablative). Post-stimulation IFN-γ levels rose steadily over the first 180 days post transplantation. IFN-γ levels were significantly lower in those with active infection compared to those without during the neutropenic period (P < .001). The assay was predictive of CMV reactivation (VL > 1000 copies/mL) post alloHCT (P = .001).

CONCLUSION

This is a promising assay to demonstrate immune recovery and predict risk of infection after alloHCT and may allow tailoring of immunosuppression, antimicrobial treatment, and prophylaxis.

Access, knowledge and experience with fluorodeoxyglucose positron emission tomography/computed tomography in infection management: a survey of Australia and New Zealand infectious diseases physicians and microbiologists

BACKGROUND

Despite fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) being funded only for staging and restaging of some malignancies in Australia, there is evidence of benefit of FDG-PET/CT for infection indications such as pyrexia of unknown origin (PUO), prolonged neutropenic fever (NF) and prosthetic device infection.

AIM

To evaluate the current knowledge, utilisation of and gaps in access to FDG-PET/CT for infectious indications by Australasian infectious diseases (ID) physicians and microbiologists.

METHODS

An online survey was administered to ID and microbiology doctors practising in adult medicine in Australia and New Zealand through two established email networks. Using targeted questions and case-based examples, multiple themes were explored, including access to FDG-PET/CT, use and perceived benefit of FDG-PET/CT in diagnosis and monitoring of non-malignant conditions such as NF and PUO, and barriers to clinical use of FDG-PET/CT.

RESULTS

A response was received from 120 participants across all states and territories. Onsite and offsite FDG-PET/CT access was 63% and 31% respectively. Eighty-six percent reported using FDG-PET/CT for one or more infection indications and all had found it clinically useful, with common indications being PUO, prosthetic device infections and use in the immunocompromised host for prolonged NF and invasive fungal infection. Thirty-eight percent reported barriers in accessing FDG-PET/CT for infection indications and 76% would utilise FDG-PET/CT more frequently if funding existed for infection indications.

CONCLUSION

Access to FDG-PET/CT in Australia and New Zealand is modest and is limited by lack of reimbursement for infection indications. There is discrepancy between recognised ID indications for FDG-PET/CT and funded indications.

FDG-PET/CT in managing infection in patients with hematological malignancy: clinician knowledge and experience in Australia

PET/CT is useful for investigation of neutropenic fever (NF) and potential invasive fungal infection (IFI) in those with hematological malignancies (HM). An online survey evaluating the utility and current practices regarding PET/CT scanning for investigation of NF was distributed to infectious diseases (ID) clinicians and hematologists via email lists hosted by key professional bodies. One-hundred and forty-five clinicians responded (120 ID; 25 hematologists). Access to PET/CT was fair but timeliness of investigation was limited (within 3 days in 35% and 46% of ID and hematology respondents, respectively). Among those with experience with PET/CT for infection (n = 109), 40% had utilized PET/CT for prolonged NF and 20% for diagnosing IFI. The majority of respondents indicated the desire to utilize PET/CT more frequently for infection indications. There is a strong desire among surveyed Australian clinicians to use PET/CT for prolonged NF and potential IFI. However, access to PET/CT is a current barrier to uptake.

Utilizing genomic analyses to investigate the first outbreak of vanA vancomycin-resistant Enterococcus in Australia with emergence of daptomycin non-susceptibility

INTRODUCTION

The majority of vancomycin-resistant Enterococcus faecium (VREfm) in Australia is of the vanB genotype. An outbreak of vanA VREfm emerged in our haematology/oncology unit between November 2014 and May 2015. The first case of daptomycin non-susceptible E. faecium (DNSEfm) detected was a patient with vanA VREfm bacteraemia who showed clinical failure of daptomycin therapy, prompting microbiologic testing confirming daptomycin non-susceptibility.

OBJECTIVES

To describe the patient profiles, antibiotic susceptibility and genetic relatedness of vanA VREfm isolates in the outbreak.

METHODS

Chart review of vanA VREfm colonized and infected patients was undertaken to describe the demographics, clinical features and outcomes of therapy. Whole genome sequencing of vanA VREfm isolates involved in the outbreak was conducted to assess clonality.

RESULTS

In total, 29 samples from 24 patients tested positive for vanA VREfm (21 screening swabs and 8 clinical isolates). Five isolates were DNSEfm (four patients colonized, one patient with bacteraemia), with only one patient exposed to daptomycin previously. In silico multi-locus sequence typing of the isolates identified 25/26 as ST203, and 1/26 as ST796. Comparative genomic analysis revealed limited core genome diversity amongst the ST203 isolates, consistent with an outbreak of a single clone of vanA VREfm.

CONCLUSIONS

Here we describe an outbreak of vanA VREfm in a haematology/oncology unit. Genomic analysis supports transmission of an ST203 vanA VRE clone within this unit. Daptomycin non-susceptibility in 5/24 patients left linezolid as the only treatment option. Daptomycin susceptibility cannot be assumed in vanA VREfm isolates and confirmatory testing is recommended.

FDG PET/CT imaging in detecting and guiding management of invasive fungal infections: a retrospective comparison to conventional CT imaging

PURPOSE

Invasive fungal infections (IFIs) are common in immunocompromised patients. While early diagnosis can reduce otherwise high morbidity and mortality, conventional CT has suboptimal sensitivity and specificity. Small studies have suggested that the use of FDG PET/CT may improve the ability to detect IFI. The objective of this study was to describe the proven and probable IFIs detected on FDG PET/CT at our centre and compare the performance with that of CT for localization of infection, dissemination and response to therapy.

METHODS

FDG PET/CT reports for adults investigated at Peter MacCallum Cancer Centre were searched using keywords suggestive of fungal infection. Chart review was performed to describe the risk factors, type and location of IFIs, indication for FDG PET/CT, and comparison with CT for the detection of infection, and its dissemination and response to treatment.

RESULTS

Between 2007 and 2017, 45 patients had 48 proven/probable IFIs diagnosed prior to or following FDG PET/CT. Overall 96% had a known malignancy with 78% being haematological. FDG PET/CT located clinically occult infection or dissemination to another organ in 40% and 38% of IFI patients, respectively. Of 40 patients who had both FDG PET/CT and CT, sites of IFI dissemination were detected in 35% and 5%, respectively (p < 0.001). Of 18 patents who had both FDG PET/CT and CT follow-up imaging, there were discordant findings between the two imaging modalities in 11 (61%), in whom normalization of FDG avidity of a lesion suggested resolution of active infection despite a residual lesion on CT.

CONCLUSION

FDG PET/CT was able to localize clinically occult infection and dissemination and was particularly helpful in demonstrating response to antifungal therapy.

Risk factors and prophylaxis against invasive fungal disease for haematology and stem cell transplant recipients: an evolving field

INTRODUCTION

Due to increasing intensity and complexity of therapies and longer survivorship, many patients with haematologic malignancy (HM) are at risk of invasive fungal disease (IFD). Mortality from IFD is high and treatment of an episode of IFD results in an excess length of hospital stay and costs and delays delivery of curative therapy of the underlying haematologic condition. Therefore, prevention and early recognition and treatment of IFD are crucial. Areas covered: Risk factors particular to certain HMs and haematopoietic stem cell transplantation, as well as those risk factors universal to all HM groups are examined. Expert commentary: Risk stratification identifies those patients who would benefit most from mould active versus yeast active prophylaxis and those who can be safely managed with monitoring and clinically driven interventions for IFD. This approach aids in antifungal stewardship.

Emerging infections caused by non-Aspergillus filamentous fungi

There are three broad groups of non-Aspergillus moulds: the mucormycetes, the hyalohyphomycetes and the phaeohyphomycetes. Infections with these pathogens are increasingly reported, particularly in the context of increasing use of immunosuppressant agents and improved diagnostics. The epidemiology of non-Aspergillus mould infections varies with geography, climate and level of immunosuppression. Skin and soft-tissue infections are the predominant presentation in the immunocompetent host and pulmonary and other invasive infections in the immunocompromised host. The more common non-Aspergillus moulds include Rhizopus, Mucor, Fusarium and Scedosporium species; however, other emerging pathogens are Rasamsonia and Verruconis species, which are discussed in this article. Outbreaks of non-Aspergillus mould infections have been increasingly reported, with contaminated medical supplies and natural disasters as common sources. Currently culture and other conventional diagnostic methods are the cornerstone of diagnosis. Molecular methods to directly detect and identify mould pathogens in tissue and body fluids are increasingly used.

Effects of scorpion and rattlesnake venoms on the canine pancreas following pancreaticoduodenal arterial injections

Three scorpion venoms caused a transitory decrease in the rate of fluid secretion and increases in the concentration, in pancreatic juice, of total protein and individual enzymes. Protein and enzyme elevations 4-7 fold over the basal levels were produced by the venom of Tityus bahiensis and 6-7 fold by venoms from Tityus serrulatus and Buthus quinquestriatus. Although these increases were smaller than those stimulated by the C-terminal octapeptide of cholecystokin (OP-CCK; 8-9 fold), the secretory responses were of longer duration, so that the total output of protein caused by each of the three venoms was significantly greater than that observed with OP-CCK. Although electron microscopy revealed evidence of widespread degeneration of acinar cells at 1 hr and more extensive damage at 2 hr following injection of scorpion venom, no free protease was detected in pancreatic secretion collected during this period. The scorpion venoms also caused hypersecretion of viscid saliva. In contrast, rattlesnake venom, had no detectable effect on salivation, pancreatic secretion or morphology of the pancreas.

Tiotidine, a new H2-receptor antagonist, is a potent inhibitor of nocturnal acid secretion in duodenal ulcer patients

The efficacy of tiotidine, a new H2-receptor antagonist, in reducing nocturnal acid secretion of duodenal ulcer patients (N = 12, ages 21-60 years) was investigated. Different doses of tiotidine, 25, 50, 100, and 150 mg or placebo, were given as a single oral dose and acid secretion collected overnight. Tiotidine produced a significant, prolonged, and dose-related reduction of the nocturnal acid secretion without important side effects. The inhibition of cumulative H+ secretion after 25, 50, 100, and 150 mg tiotidine was 80, 89, 96, and 98% of that observed after placebo, while 300 mg of cimetidine caused an 87% inhibition. Compared to cimetidine, tiotidine appears to be approximately eight times more potent on a molar basis than cimetidine as an inhibitor of acid secretion, and the tiotidine effect is more prolonged. This strong and safe H2-receptor antagonist may be an important addition to the treatment of acid hypersecretory states.

Studies of pure pancreatic secretions in chronic alcoholic subjects without pancreatic insufficiency

To determine the role alcohol might play in altering pancreatic function, we have examined pure pancreatic juice, obtained by endoscopic cannulation of the pancreatic duct, from a group of 10 chronic alcoholic subjects without history or clinical or laboratory evidence of pancreatic disease and compared the results with those obtained from 15 healthy, non-alcoholic subjects. These findings confirm observations in experimental animals made by others and support the hypothesis that chronic alcohol abuse may damage the pancreas via a sequence of events involving protein hypersecretion. Increase in concentration was not uniform for all proteins measured. Unexpectedly, chronic alcoholics exhibited a highly significant elevation (two- to three-fold over normal) in trypsinogen, in contrast to statistically insignificant increases of other zymogens and trypsin inhibitor. The strikingly increased ratio of trypsinogen to trypsin inhibitor observed in all our alcoholic patients may indicate a weakening of the defence mechanism provided by the trypsin inhibitor against premature intraductal activation of zymogens and explain the predisposition of these patients to pancreatitis.

alpha-Amylase of human pure pancreatic juice: effects of pancreatic disease and the occurrence of variant forms in pancreatic juice from healthy volunteers

Pure pancreatic juice (PPJ) from healthy human volunteers and from patients with pancreatic or liver disease was subjected to isoelectric focussing (IEF) and assayed for alpha-amylase activity. In PPJ from most normals, a single predominant form of amylase was found, comprising congruent to 83% of the total activity recovered, and having pIapp congruent to pH 6.8. In PPJ from six normals, variant principal forms of amylase were found at pH congruent to 6.4 or pH congruent to 7.3, in addition to the peak at pH 6.8. IEF patterns of PPJ from individuals with pancreatic or liver disease were indisquishable from patterns obtained with PPJ from the control group of healthy volunteers.

Highly purified basal lateral plasma membranes from rat duodenum. Physical criteria for purity

Preparations of intestinal epithelial cell basal lateral plasma membranes were analyzed with free flow electrophoresis and density perturbation with digitonin. The initial basal lateral membrane preparations were obtained by equilibrium density gradient centrifugation after two different schemes of homogenization and differential sedimentation (A.K. Mircheff, C.H. van Os, and E.M. Wright. 1978. Membr. Biochem. 1:177, and A.K. Mircheff, S.D. Hanna, M.W. Walling, and E.M. Wright. 1979. Prep. Biochem. 9:33. In these preparations, Na,K-ATPase, a marker for the basal lateral mambrane, was purified 16- to 18-fold over the initial homogenate. The preparations were also enriched in NADPH-cytochrome c reductase, alkaline phosphatase, acid phosphatase, and galactosyltransferase. Both free-flow electrophoresis, which separates on the basis of surface charge, and density perturbation with digitonin, which depends on a specific interaction of digitonin with cholesterol-rich membranes, resolved the preparation into three populations of particles. The major population, which represented basal lateral membranes purified 20- to 32-fold with respect to the initial homogenate, contained Na,K-ATPase, alkaline phosphatase, adenylate cyclase, and acid phosphatase. A second population was defined by its content of NADPH-cytochrome c reductase, and the third was defined by its content of galactosyltransferase. Guanylate cyclase appeared to be partitioned between the Na,K-ATPase-rich and NADPH-cytochrome c reductase-rich populations. Galactosyltransferase is also present in fractions which contain the Na,K-ATPase-rich membranes, but the present data cannot exclude the possibility of spillover by the adjacent, galactosyltransferase-rich population. This work emphasizes the importance of multiple, physical criteria for purity in the isolation of subcellular components.

Profiles of pure pancreatic secretions in patients with acute pancreatitis: the possible role of proteolytic enzymes in pathogenesis

Studies have been performed on pure pancreatic juice obtained by direct cannulation of the pancreatic duct in 2 patients with acute pancreatitis. The striking abnormalities observed, which were in marked contrast to our observations in 15 normal subjects, were high concentrations of protein throughout the period of secretin stimulation and the sporadic appearance of free proteolytic activity in many 1-min specimens throughout the collection period. In 1 subject repeat studies were performed after resolution of the pancreatitis when the profile observed was normal. Our findings are consistent with the hypothesis that obstruction of ductules and intraductal activation of zymogens may be important in the pathogenesis of acute pancreatitis.

Choledochal cyst presenting as acute pancreatitis: evaluation with endoscopic retrograde cholangiopancreatography

A unusual case of choledochal cyst in an adult presenting as acute pancreatitis is described. Subsequent evaluation by ERCP revealed two atypical features, involvement of the cystic duct (proximal dilatation) and a long (six times normal) intrapancreatic common channel, which may be etiologically related to the pancreatitis.

The spectrum of paracetamol (acetaminophen) overdose: clinical and epidemiological studies

In a regional survey of paracetamol overdose, 201 patients were admitted to hospital over 12 months. Chronic alcoholism was present in 10% of cases. Over 25% of patients were females aged 20 years or less. Initial blood paracetamol levels were in the toxic range in 16% and histologically severe liver damage eventually found in 20% of those biopsied. This finding corresponded to a serum aspartate aminotransferase of 600 i.u./l or more. Renal failure severe enough to require peritoneal dialysis developed in 1%. Elevated serum amylase was recorded in 22% of a 108-patient subset. Evidence of myocardial damage was found in 11.6% of an eighty-six patient subset. An unfavourable prognosis was indicated by a prothrombin ratio of 20% or less and hepatic coma, the overall mortality being 3.5%. The apparent safety of this useful analgesic is compromized by its widespread employment in parasuicide. This, the insidious and delayed onset of toxicity in overdose and ineffectiveness of late treatment argues for controlling availability to the general public.

Paracetamol (acetaminophen) kinetics in patients with Gilber's syndrome

The pahrmacokinetics of paracetamol after intravenous and oral administration has been studied in 6 patients with Gilbert's syndrome, and 6 healthy controls. Paracetamol clearance was significantly less in the patients (255 ml/min SE +/- 23 ml/min) than in the normal subjects (352 ml/min SE +/- 40 ml/min). Moreover, whilst paracetamol concentrations declined monoexponentially in the patients, the decline was biexponential in the controls. No difference in the bioavailability of 500 mg paracetamol given orally was observed between the two groups. The results suggest that not only is paracetamol elimination impaired in Gilbert's syndrome, but that its distribution kinetics are also abnormal. Both these findings could be attributed to a decrease in hepatic glucuronyl transferase activity.

A comparative study of double contrast and single contrast barium meals with endoscopic arbitration in the diagnosis of peptic ulcer

The study compares the ability of a simple double contrast technique with our standard single contrast barium meal to diagnose peptic ulceration. Two hundred and six patients were randomly allocated to either examination. Endoscopy was used as the definitive diagnostic procedure. Deformity of the duodenal cap was more accurately detected by the double contrast technique (P less than 0.01). There was no significant difference in the detection rates for duodenal ulcer. False positive or false negative diagnoses of duodenal pathology were similar by both techniques. The incidence of gastric ulceration in the series was too low for statistical analysis.

Fulminant Wilson's disease with haemolysis and renal failure: copper studies and assessment of dialysis regimens

Two girls, aged 12 and 17 years, presented with hepatocellular dysfunction and severe haemolysis due to Wilson's disease (hepatolenticular degeneration). This was accompanied by acute renal failure. In the absence of renal function sufficient for the urinary excretion of penicillamine, studies were performed to assess the potential of peritoneal dialysis, ascites removal by ultrafiltration-reinfusion, and haemodialysis as alternative excretory pathways for copper. The greatest amount of copper, as judged by rising bath concentrations, seemed to be eliminated with haemodialysis. But this was accompanied by a progressive increase in serum copper concentrations with rapid clinical and biochemical deterioration leading to death within 48 hours. A small amount of copper was lost with ascites removal. Significant amounts of copper were removed during peritoneal dialysis (36 mumol/day (2287 microgram/day)), although a clinical response was not evident before haemodialysis was introduced. The administration of penicillamine orally, intravenously, or intraperitoneally produced no measurable increase in copper excretion into the peritoneal dialysate. Hence peritoneal dialysis alone appears to offer the greatest potential benefit with regard to both eliminating copper and altering the course of this fulminant form of Wilson's disease.

Liver function and structure in survivors of acetaminophen poisoning. A follow-up study of serum bile acids and liver histology

A series of 30 patients, hospitalized with acetaminophen overdose, were studied during initial admission and again three months later. The quantity of acetaminophen ingested varied from 5 to 50 g and 19 patients developed raised transaminase levels in the serum during the initial period. Liver damage, on the basis of needle biopsy findings, was categorized as severe in 5, moderate in 7, and mild or minimal in 18 patients. At three months' follow-up all but one of the biochemical indicants of liver damage had reverted to normal in all patients. The exception was the serum total bile acids. Residual changes found on liver biopsy at three months were minimal and nonspecific, apart from one previously severely affected patient in whom there was evidence of scarring. It is concluded that in the usual spectrum of acetaminophen poisoning requiring hospitalization there is no evidence of lasting liver damage.

Iron-transport characteristics of vesicles of brush-border and basolateral plasma membrane from the rat enterocyte

Vesicles of brush-border and basolateral plasma membrane were prepared from enterocytes of the rat small intestine. The separateness of these two varieties of plasma membrane was confirmed by appropriate enzyme assays. The uptake of Fe2+ by these membrane vesicles was studied, and the results suggest differences between the two types of membrane in both the amount of Fe2+ taken up and in the rate of uptake. At low (up to 3 micrometer) concentrations of Fe2+, uptake by both membrane types showed evidence of saturation and could be blocked with the thiol inactivator N-ethylmaleimide. The studies suggest that Fe2+ is taken into an osmotically active space by a process of facilitated diffusion at low concentrations, but that at higher concentrations the process appeared to obey first-order kinetics. The data provide further evidence for the existence of functional polarity in the epithelial cell of the small intestine.

Gastric emptying in coeliac disease

Images

The binding of a glycopeptide component of wheat gluten to intestinal mucosa of normal and coeliac human subjects

A carbohydrate-containing component of wheat gluten (glyc-gli) has been prepared which is toxic to coeliac intestinal mucosa. Its amino acid composition is uniquely different from that of the parent gluten and from alpha-gliadin. This glyc-gli material has been shown to bind to membrane components of the coeliac intestinal cell but to bind only poorly to normal intestinal cell membranes. Furthermore this binding can be interfered with by exogenous free carbohydrate suggesting that the toxic moiety of gluten acts in an analagous way to plant lectins. These data suggest that the underlying defect in coeliac disease is related to the composition of the surface membrane of the enterocyte.

Diagnosis of Giardia lamblia infection as a cause of diarrhoea

Retrospective analysis of the records of 31 patients diagnosed as having Giardia lamblia infection in our hospital over a five-year period suggests that the condition is not considered often or early enough. Adult patients particularly "suffer" more, having to endure more investigations (mean of 16) than do symptomatic children (mean of 6) before a diagnosis is made. The length of time to reach the diagnosis from first referral further supports this view, being almost seven weeks in adults and three weeks in children--both groups having had symptoms for an average of seven months before referral.

Caroli's disease with intrahepatic gall-stones and salmonella infection

At operation for small bowel intussusception, a 26-year-old man was found to have an enlarged liver and spleen. Subsequent investigations suggested bile passage infection associated with numerous intrahepatic gall-stones but symptomatic cholangitis did not present until 5 months later. Retrograde cholangiography showed cavernous ectasia of the bile ducts which contained gall-stones.

Evaluation of paracetamol-induced damage in liver biopsies. Acute changes and follow-up findings

In 100 patients who had taken an acute overdose of paracetamol the liver was biopsied percutaneously on the 4th day or as soon thereafter as recovery of the clotting mechanism allowed. A system for grading the histological changes in the liver is described. The hallmark of severe (grade III) damage is centrizonal necrosis, for which there is probably a dosage threshold. Consequent changes include phagocytosis of cell debris, reticulin collapse, and an inflammatory infiltration; acidophil degeneration of hepatocytes is sometimes prominent; regenerative growth is already evident after 4 days. Mild (grade I) damage is characterized by excess of lipofuscin pigment in centrizonal hepatocytes, sparse focal necrosis of liver cells, and some phagocytosis of lipofuscin. The findings in moderate (grade II) damage are similar but more pronounced. Five patients died in acute hepatic failure, and 22/100 showed severe (grade III) changes but survived. Forty-nine patients representing all three grades of liver damage were rebiopsied after 3 months. Central necrotic zones were found to have been completely reconstituted leaving only minor abnormalities except for one patient who showed mild centrilobular fibrosis and scarring of a nonprogressive nature.