Validated assays for the quantification of C9orf72 human pathology

A repeat expansion mutation in the C9orf72 gene is the leading known genetic cause of FTD and ALS. The C9orf72-ALS/FTD field has been plagued by a lack of reliable tools to monitor this genomic locus and its RNA and protein products. We have validated assays that quantify C9orf72 pathobiology at the DNA, RNA and protein levels using knock-out human iPSC lines as controls. Here we show that single-molecule sequencing can accurately measure the repeat expansion and faithfully report on changes to the C9orf72 locus in what has been a traditionally hard to sequence genomic region. This is of particular value to sizing and phasing the repeat expansion and determining changes to the gene locus after gene editing. We developed ddPCR assays to quantify two major C9orf72 transcript variants, which we validated by selective excision of their distinct transcriptional start sites. Using validated knock-out human iPSC lines, we validated 4 commercially available antibodies (of 9 tested) that were specific for C9orf72 protein quantification by Western blot, but none were specific for immunocytochemistry. We tested 15 combinations of antibodies against dipeptide repeat proteins (DPRs) across 66 concentrations using MSD immunoassay, and found two (against poly-GA and poly-GP) that yielded a 1.5-fold or greater signal increase in patient iPSC-motor neurons compared to knock-out control, and validated them in human postmortem and transgenic mouse brain tissue. Our validated DNA, RNA and protein assays are applicable to discovery research as well as clinical trials.

Microscale modelling of dielectrophoresis assembly processes

This work presents a microscale approach for simulating the dielectrophoresis assembly of polarizable particles under an external electric field. The model is shown to capture interesting dynamical and topological features, such as the formation of chains of particles and their incipient aggregation into hierarchical structures. A quantitative characterization in terms of the number and size of these structures is also discussed. This computational model could represent a viable numerical tool to study the mechanical properties of particle-based hierarchical materials and suggest new strategies for enhancing their design and manufacture. This article is part of the theme issue 'Progress in mesoscale methods for fluid dynamics simulation'.

Over half of seniors who start oral bisphosphonate therapy are exposed for 3 or more years: novel rolling window approach and patterns of use

Most adherence studies only consider treatment following a first prescription. Using an extended follow-up, we found that 60% of seniors starting oral bisphosphonate therapy were exposed for ≥ 3 years (48% for ≥ 5 years). Studies are needed to examine the benefits and harms of continuing bisphosphonate therapy beyond 3 years.

INTRODUCTION

The purpose of this study was to identify and describe patterns of long-term oral bisphosphonate use among seniors using a novel methodological approach that considers extended follow-up.

METHODS

Among Ontarians aged 66 years or older, we identified subjects with a first dispensing of alendronate or risedronate between November 2000 and December 2016. We followed them until death or December 2019 to identify patients with ≥ 3 years of bisphosphonate use, defined as a proportion of days covered ≥ 80%, using 3-year rolling windows. We calculated the proportion of patients with long-term therapy (≥ 3 years of use) using Kaplan-Meier estimates. We described patterns of long-term use and compared patient characteristics between patients with and without long-term therapy.

RESULTS

We identified 260,784 eligible seniors initiating bisphosphonate therapy. Of these, 60% continued therapy ≥ 3 years (77% women), and 48% continued ≥ 5 years. Characteristics did not meaningfully differ between patients with or without long-term therapy. The median length of long-term therapy was 7.0 (IQR 5.1) years for women and 6.1 (IQR 4.3) years for men. Only 20% experienced a treatment gap before long-term therapy, yet 50% experienced a treatment gap of ≥ 120 days after a median 5.3 years of therapy. Eighty-one percent who returned to therapy following a treatment gap re-initiated an oral bisphosphonate, with 18% switching to denosumab.

CONCLUSIONS

Among seniors initiating oral bisphosphonates, we found that 60% receive at least 3 years of therapy when using an extended follow-up. Studies are needed to examine the benefits and harms of continuing bisphosphonate therapy beyond 3 years.

Antibiotic Prescribing Choices and Their Comparative C. Difficile Infection Risks: A Longitudinal Case-Cohort Study

BACKGROUND

Antibiotic use is the strongest modifiable risk factor for the development of Clostridioides difficile infection, but prescribers lack quantitative information on comparative risks of specific antibiotic courses. Our objective was to estimate risks of C. difficile infection associated with receipt of specific antibiotic courses.

METHODS

We conducted a longitudinal case-cohort analysis representing over 90% of Ontario nursing home residents, between 2012 and 2017. Our primary exposure was days of antibiotic receipt in the prior 90 days. Adjustment covariates included: age, sex, prior emergency department or acute care stay, Charlson comorbidity index, prior C. difficile infection, acid suppressant use, device use, and functional status. We examined incident C. difficile infection, including cases identified within the nursing home, and those identified during subsequent hospital admissions. Adjusted and unadjusted regression models were used to measure risk associated with 5- to 14-day courses of 18 different antibiotics.

RESULTS

We identified 1708 cases of C. difficile infection (1.27 per 100 000 resident-days). Longer antibiotic duration was associated with increased risk: 10- and 14-day courses incurred 12% (adjusted relative risk [ARR] = 1.12, 95% confidence interval [CI]: 1.09, 1.14) and 27% (ARR = 1.27, 95% CI: 1.21,1.30) more risk compared to 7-day courses. Among 7-day courses with similar indications: moxifloxacin resulted in 121% more risk than amoxicillin (ARR = 2.21, 95% CI: 1.67, 3.08), ciprofloxacin engendered 89% more risk than nitrofurantoin (ARR = 1.89, 95% CI: 1.45, 2.68), and clindamycin resulted in 112% (ARR = 2.12, 95% CI: 1.32, 3.78) more risk than cloxacillin.

CONCLUSIONS

C. difficile infection risk increases with antibiotic duration, and there are wide disparities in risks associated with antibiotic courses used for similar indications.

Virtual learning collaboratives to improve urine culturing and antibiotic prescribing in long-term care: controlled before-and-after study

BACKGROUND

Urine culturing practices are highly variable in long-term care and contribute to overprescribing of antibiotics for presumed urinary tract infections. The purpose of this study was to evaluate the use of virtual learning collaboratives to support long-term care homes in implementing a quality improvement programme focused on reducing unnecessary urine culturing and antibiotic overprescribing.

METHODS

Over a 4-month period (May 2018-August 2018), 45 long-term care homes were self-selected from five regions to participate in virtual learning collaborative sessions, which provided an orientation to a quality improvement programme and guidance for implementation. A process evaluation complemented the use of a controlled before-and-after study with a propensity score matched control group (n=127) and a difference-in-difference analysis. Primary outcomes included rates of urine cultures performed and urinary antibiotic prescriptions. Secondary outcomes included rates of emergency department visits, hospital admission and mortality. An 18-month baseline period was compared with a 16-month postimplementation period with the use of administrative data sources.

RESULTS

Rates of urine culturing and urinary antibiotic prescriptions per 1000 resident days decreased significantly more among long-term care homes that participated in learning collaboratives compared with matched controls (differential reductions of 19% and 13%, respectively, p<0.0001). There was no statistically significant changes to rates of emergency department visits, hospital admissions or mortality. These outcomes were observed with moderate adherence to the programme model.

CONCLUSIONS

Rates of urine culturing and urinary antibiotic prescriptions declined among long-term care homes that participated in a virtual learning collaborative to support implementation of a quality improvement programme. The results of this study have refined a model to scale this programme in long-term care.

The Urine-culturing Cascade: Variation in Nursing Home Urine Culturing and Association With Antibiotic Use and Clostridiodes difficile Infection

BACKGROUND

Rates of antibiotic use vary widely across nursing homes and cannot be explained by resident characteristics. Antibiotic prescribing for a presumed urinary tract infection is often preceded by inappropriate urine culturing. We examined nursing home urine-culturing practices and their association with antibiotic use.

METHODS

We conducted a longitudinal, multilevel, retrospective cohort study based on quarterly nursing home assessments between April 2014 and January 2017 in 591 nursing homes and covering >90% of nursing home residents in Ontario, Canada. Nursing home urine culturing was measured as the proportion of residents with a urine culture in the prior 14 days. Outcomes included receipt of any systemic antibiotic and any urinary antibiotic (eg, nitrofurantoin, trimethoprim/sulfonamides, ciprofloxacin) in the 30 days after the assessment and Clostridiodes difficile infection in the 90 days after the assessment. Adjusted Poisson regression models accounted for 14 resident covariates.

RESULTS

A total of 131 218 residents in 591 nursing homes were included; 7.9% of resident assessments had a urine culture in the prior 14 days; this proportion was highly variable across the 591 nursing homes (10th percentile = 3.4%, 90th percentile = 14.3%). Before and after adjusting for 14 resident characteristics, nursing home urine culturing predicted total antibiotic use (adjusted risk ratio [RR] per doubling of urine culturing, 1.21; 95% confidence interval [CI], 1.18-1.23), urinary antibiotic use (RR, 1.33; 95% CI, 1.28-1.38), and C. difficile infection (incidence rate ratio, 1.18; 95% CI, 1.07-1.31).

CONCLUSIONS

Nursing homes have highly divergent urine culturing rates; this variability is associated with higher antibiotic use and rates of C. difficile infection.

Reducing unnecessary urine culturing and antibiotic overprescribing in long-term care: a before-and-after analysis

BACKGROUND

Antibiotic use in long-term care homes is highly variable. High rates of antibiotic use are associated with antibiotic resistance and Clostridium difficile infection. We asked 2 questions regarding a program designed to improve diagnosis and management of urinary tract infections in long-term care: whether the program decreased urine culturing and antibiotic prescribing rates and whether specific strategies of the program were more or less likely to be adopted.

METHODS

The study included 10 long-term care homes in Ontario, Canada, between December 2015 and May 2017. We assessed the implementation of the program's 9 strategies via semistructured interviews with key informants. Using a before-and-after study design, and on the basis of monthly facility-level records, we measured changes in the rates of urine specimens sent for culture and susceptibility testing, prescriptions for antibiotics commonly used to treat urinary tract infections and total antibiotic prescriptions, using Poisson regression.

RESULTS

Participating homes implemented an average of 6.1 of the 9 strategies. Urine culturing decreased from 3.20 to 2.09 per 1000 resident-days from the baseline to the intervention phase (adjusted incidence rate ratio [IRR_adjusted] = 0.72, 95% confidence interval [CI] 0.63-0.82), urinary antibiotic prescriptions fell from 1.52 to 0.83 per 1000 resident-days (IRR_adjusted = 0.60, 95% CI 0.47-0.74) and total antibiotic prescriptions fell from 3.85 to 2.60 per 1000 resident-days (IRR_adjusted = 0.74, 95% CI 0.65-0.83). After adjusting for secular trends, these reductions were not statistically significant.

INTERPRETATION

We demonstrated a reduction in urine culturing and antibiotic use following implementation of the Urinary Tract Infection Program. This initial analysis supports a broader implementation of this program, although ongoing evaluation is required to monitor secular trends in urine culturing and antibiotic use.

Regional variability in outpatient antibiotic use in Ontario, Canada: a retrospective cross-sectional study

BACKGROUND

Regional variability in antibiotic use is associated with both antibiotic overuse and antimicrobial resistance. Our objectives were to benchmark outpatient antibiotic use and to evaluate geographic variability among health regions in the province of Ontario, Canada.

METHODS

This was a cross-sectional study of antibiotics dispensed from outpatient retail pharmacies in Ontario between March 2016 and February 2017. We analyzed variability in the number of antibiotic prescriptions dispensed per 1000 population among Ontario's 14 health regions with crude and adjusted Poisson regression models. Adjusted models controlled for rurality, 4 physician characteristics and 6 population characteristics.

RESULTS

There were 8 352 578 antibiotics dispensed during the 1-year study period or 621 per 1000 population. The most commonly prescribed antibiotic classes were narrow-spectrum penicillins, macrolides, first-generation cephalosporins and second-generation fluoroquinolones, with adult women receiving the highest rate of prescriptions: 985 antibiotic prescriptions per 1000 population. There was geographic variability in total and class-specific antibiotic use. In the health region with the highest use 778 antibiotics were dispensed per 1000 population whereas in the health region with the lowest use 534 antibiotics were dispensed per 1000 population. The adjusted marginal standardized antibiotic prescription rates for the health regions with the highest and lowest use were 787 (95% confidence interval [CI] 658-934) and 546 (95% CI 494-606) antibiotic prescriptions per 1000 population, respectively.

INTERPRETATION

We described baseline antibiotic usage in Ontario over a 12-month period, noting variability among some health regions. Our findings highlight the need for interventions to optimize antibiotic use and slow the emergence of antimicrobial resistance.

High-throughput synthesis and characterization of nanocrystalline porphyrinic zirconium metal-organic frameworks

We describe and employ a high-throughput screening method to accelerate the synthesis and identification of pure-phase, nanocrystalline metal-organic frameworks (MOFs). We demonstrate the efficacy of this method through its application to a series of porphyrinic zirconium MOFs, resulting in the isolation of MOF-525, MOF-545, and PCN-223 on the nanoscale.

Susceptibilities of clinical Clostridium difficile isolates to antimicrobials: a systematic review and meta-analysis of studies since 1970

OBJECTIVES

Although exposure to antibiotics can cause Clostridium difficile infection, certain antibiotics are used to treat C. difficile. Measurements of antimicrobial C. difficile activity could help to identify antibiotic risk and emergent resistance. Here, we describe publication patterns relating to C. difficile susceptibilities and estimate minimum inhibitory concentrations (MIC) for antibiotic classes in the published literature between January 1970 and June 2014.

METHODS

We queried PUBMED and EMBASE for studies reporting antibiotic C. difficile MIC in English or French. We used mixed-effects models to obtain pooled estimates of antibiotic class median MIC (MIC₅₀), 90th percentile of MIC (MIC₉₀), and MIC₉₀:MIC₅₀ ratio.

RESULTS

Our search identified 182 articles that met our inclusion criteria, of which 27 were retained for meta-analysis. Aminoglycosides (MIC₅₀ 120 mg/L, 95% CI 62-250), 3rd (MIC₅₀ 75 mg/L, 95% CI 39-130) and 2nd generation cephalosporins (MIC₅₀ 64 mg/L, 95% CI 27-140) had the least C. difficile activity. Rifamycins (MIC₅₀ 0.034 mg/L, 95% CI 0.012-0.099) and tetracyclines (MIC₅₀ 0.29 mg/L, 95% CI 0.054-1.7) had the highest level of activity. The activity of 3rd generation cephalosporins was more than three times lower than that of 1st generation agents (MIC₅₀ 19 mg/L, 95% CI 7.0-54). Time-trends in MIC₅₀ were increasing for carbapenems (70% increase per 10 years) while decreasing for tetracyclines (51% decrease per 10 years).

CONCLUSIONS

We found a 3500-fold variation in antibiotic C. difficile MIC₅₀, with aminoglycosides as the least active agents and rifamycins as the most active. Further research is needed to determine how in vitro measures can help assess patient C. difficile risk and guide antimicrobial stewardship.

Abstract PD5-05: Metabolic obesity, adipose inflammation and aromatase: Potential drivers of breast cancer risk in women with normal body mass index

Background: Elevated body mass index (BMI) is associated with increased risk of postmenopausal breast cancer, which may be partly attributable to an inflammation-aromatase axis. Most individuals with elevated BMI harbor white adipose tissue inflammation (WATi), defined by the presence of crown-like structures in the breast (CLS-B). CLS-B are composed of a dead/dying adipocyte surrounded by CD68+ macrophages. This inflammation is associated with activation of NF-κB and elevated expression of aromatase, which could contribute to tumor development. Additionally, WATi correlates with several circulating changes, including hyperinsulinemia, which increase breast cancer risk. Although breast WATi correlates with rising BMI, it is also present in some normal BMI individuals. Beyond inherited germline syndromes, the etiology of breast cancer in individuals with normal BMI is not well understood. Here we examined the impact of breast WATi on breast aromatase expression and circulating factors in women with normal BMI.

Methods: Non-tumorous breast tissue and fasting blood were collected from 72 women with BMI &lt; 25 kg/m2 undergoing mastectomy at MSKCC. Breast inflammation was detected by the presence of CLS-B using CD68 immunohistochemistry. The primary objective was to determine if breast WATi in normal BMI individuals correlates with elevated aromatase levels in the breast, measured by qPCR, western blotting, immunofluorescence and enzyme activity. Secondary objectives included assessment of breast adipocyte size and circulating metabolic and inflammatory factors.

Results: Breast inflammation was present in 39% of women. Median BMI was 23.0 (range 18.4 to 24.9) in women with breast WATi versus 21.8 (range 17.3 to 24.6) in those without inflammation (P=0.04). Aromatase mRNA expression was positively correlated with WATi (CLS-B/cm2; P=0.002). Those with severe WATi had highest aromatase mRNA levels, compared to those with no or mild WATi (P=0.005). Aromatase protein, assessed by measuring adipose stromal cell-specific immunofluorescence or western blotting, and activity were also higher in CLS-B+ cases compared to CLS-B- (P&lt;0.001). Breast WATi correlated with larger adipocytes (P=0.01) and higher circulating levels of C-reactive protein, leptin, insulin, and triglycerides (P&lt;0.05). Insulin resistance, characterized by the homeostasis model (HOMA2-IR), correlated with breast WATi (P=0.004). Finally, leptin, a known inducer of aromatase and driver of cancer growth, correlated with higher breast aromatase levels (P=0.02) and larger adipocytes (P&lt;0.01).

Conclusions: A metabolically unhealthy state occurs in women with inflamed breast adipose despite having a normal BMI. This subclinical inflammatory state is characterized by elevated aromatase in the breast, insulin resistance, and dysplipidemia. The presence of enlarged adipocytes in the breasts of normal BMI women with inflammation suggests a state of hyperadiposity which could not be predicted based on BMI alone. These findings indicate that normal BMI metabolic obesity may be associated with increased cancer risk. Our results suggest that objective measurements of adiposity rather than BMI may help to identify individuals at increased risk for disease.

Citation Format: Iyengar NM, Brown KA, Zhou XK, Subbaramaiah K, Giri DD, Gucalp A, Howe LR, Zahid H, Bhardwaj P, Wendel NK, Falcone DJ, Morrow M, Wang H, Williams S, Pollak M, Hudis CA, Dannenberg AJ. Metabolic obesity, adipose inflammation and aromatase: Potential drivers of breast cancer risk in women with normal body mass index [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr PD5-05.

Expression of CD11c and EMR2 on neutrophils: potential diagnostic biomarkers for sepsis and systemic inflammation

There is a need for cellular biomarkers to differentiate patients with sepsis from those with the non-infectious systemic inflammatory response syndrome (SIRS). In this double-blind study we determined whether the expression of known (CD11a/b/c, CD62L) and putative adhesion molecules [CD64, CD97 and epidermal growth factor (EGF)-like molecule containing mucin-like hormone receptor (EMR2)] on blood neutrophils could serve as useful biomarkers of infection and of non-infectious SIRS in critically ill patients. We studied 103 patients with SIRS, 83 of whom had sepsis, and 50 healthy normal subjects, using flow cytometry to characterize neutrophils phenotypically in whole blood samples. Patients with SIRS had an increased prevalence of neutrophils expressing CD11c, CD64 and EMR2 in comparison with healthy subjects (P < 0.001), but normal expression of CD11a, CD11b, CD62L and CD97. An increase in the percentage of neutrophils bearing CD11c was associated with sepsis, EMR2 with SIRS and CD64 with sepsis and SIRS. Neutrophils expressing CD11c had the highest sensitivity (81%) and specificity (80%) for the detection of sepsis, and there was an association between the percentage of neutrophils expressing EMR2 and the extent of organ failure (P < 0.05). Contrary to other reports, we did not observe an abnormal expression of CD11b or CD62L on neutrophils from patients with SIRS, and suggest that this discrepancy is due to differences in cell processing protocols. We propose that blood neutrophils expressing CD11c and EMR2 be considered as potential biomarkers for sepsis and SIRS, respectively.

Trends in Antibiotic Use and Nosocomial Pathogens in Hospitalized Veterans With Pneumonia at 128 Medical Centers, 2006-2010

BACKGROUND

In 2005, pneumonia practice guidelines recommended broad-spectrum antibiotics for patients with risk factors for nosocomial pathogens. The impact of these recommendations on the ability of providers to match treatment with nosocomial pathogens is unknown.

METHODS

Among hospitalizations with a principal diagnosis of pneumonia at 128 Department of Veterans Affairs medical centers from 2006 through 2010, we measured annual trends in antibiotic selection; initial blood or respiratory cultures positive for methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa, and Acinetobacter species; and alignment between antibiotic coverage and culture results for MRSA and P. aeruginosa, calculating sensitivity, specificity, and diagnostic odds ratio using a 2 × 2 contingency table.

RESULTS

In 95 511 hospitalizations for pneumonia, initial use of vancomycin increased from 16% in 2006 to 31% in 2010, and piperacillin-tazobactam increased from 16% to 27%, and there was a decrease in both ceftriaxone (from 39% to 33%) and azithromycin (change from 39% to 36%) (P < .001 for all). The proportion of hospitalizations with cultures positive for MRSA decreased (from 2.5% to 2.0%; P < .001); no change was seen for P. aeruginosa (1.9% to 2.0%; P = .14) or Acinetobacter spp. (0.2% to 0.2%; P = .17). For both MRSA and P. aeruginosa, sensitivity increased (from 46% to 65% and 54% to 63%, respectively; P < .001) and specificity decreased (from 85% to 69% and 76% to 68%; P < .001), with no significant changes in diagnostic odds ratio (decreases from 4.6 to 4.1 [P = .57] and 3.7 to 3.2 [P = .95], respectively).

CONCLUSIONS

Between 2006 and 2010, we found a substantial increase in the use of broad-spectrum antibiotics for pneumonia despite no increase in nosocomial pathogens. The ability of providers to accurately match antibiotic coverage to nosocomial pathogens remains low.

Automated analysis of respiratory behavior in extremely preterm infants and extubation readiness

BACKGROUND

Rates of extubation failure of extremely preterm infants remain high. Analysis of breathing patterns variability during spontaneous breathing under endotracheal tube continuous positive airway pressure (ETT-CPAP) is a potential tool to predict extubation readiness.

OBJECTIVE

To investigate if automated analysis of respiratory signals would reveal differences in respiratory behavior between infants that were successfully extubated or not.

METHODS

Respiratory Inductive Plethysmography (RIP) signals were recorded during ETT-CPAP just prior to extubation. Signals were digitized, and analyzed using an Automated Unsupervised Respiratory Event Analysis (AUREA). Extubation failure was defined as reintubation within 72 hr. Statistical differences between infants who were successfully extubated or failed were calculated.

RESULTS

A total of 56 infants were enrolled and one was excluded due to instability during the ETT-CPAP; 11 out of 55 infants studied failed extubation (20%). No differences in demographics were observed between the success and failure groups. Significant differences on the variability of some respiratory parameters or 'metrics' estimated by AUREA were observed between the 2 groups. Indeed, a simple classification using the variability of two metrics of respiratory behavior predicted extubation failure with high accuracy.

CONCLUSION

Automated analysis of respiratory behavior during a short ETT-CPAP period may help in the prediction of extubation readiness in extremely preterm infants.

Belatacept-based immunosuppression in de novo liver transplant recipients: 1-year experience from a phase II randomized study

This exploratory phase II study evaluated the safety and efficacy of belatacept in de novo adult liver transplant recipients. Patients were randomized (N = 260) to one of the following immunosuppressive regimens: (i) basiliximab + belatacept high dose [HD] + mycophenolate mofetil (MMF), (ii) belatacept HD + MMF, (iii) belatacept low dose [LD] + MMF, (iv) tacrolimus + MMF, or (v) tacrolimus alone. All received corticosteroids. Demographic characteristics were similar among groups. The proportion of patients who met the primary end point (composite of acute rejection, graft loss, death by month 6) was higher in the belatacept groups (42–48%) versus tacrolimus groups (15–38%), with the highest number of deaths and grafts losses in the belatacept LD group. By month 12, the proportion surviving with a functioning graft was higher with tacrolimus + MMF (93%) and lower with belatacept LD (67%) versus other groups (90%: basiliximab + belatacept HD; 83%: belatacept HD; 88%: tacrolimus). Mean calculated GFR was 15–34 mL/min higher in belatacept-treated patients at 1 year. Two cases of posttransplant lymphoproliferative disease and one case of progressive multifocal leukoencephalopathy occurred in belatacept-treated patients. Follow-up beyond month 12 revealed an increase in death and graft loss in another belatacept group (belatacept HD), after which the study was terminated.

The impact of hepatitis C burden: an evidence-based approach

BACKGROUND

Infection with the hepatitis C virus (HCV) has been considered a major cause of mortality, morbidity and resource utilisation in the US. In addition, HCV is the main cause of hepatocellular cancer (HCC) in the US. Recent developments in the diagnosis and treatment of HCV, including new recommendations pertaining to screening for HCV by the Centers for Disease Control and Prevention and newer treatment regimens with high efficacy, short duration and the potential for interferon-free therapies, have energised the health care practitioners regarding HCV management.

AIM

To assess the full impact of HCV burden on clinical, economic and patient-reported outcomes.

METHODS

An expert panel was convened to assess the full impact of HCV burden on a number of important outcomes using an evidence-based approach predicated on Grading of Recommendations Assessment, Development and Evaluation methodology. The literature was summarised, graded using an evidence-based approach and presented during the workshop. Workshop presentations were intended to review recent, relevant evidence-based literature and provide graded summary statements pertaining to HCV burden on topics including the relationships between HCV and the development of important outcomes.

RESULTS

The associations of HCV with cirrhosis, HCC, liver-related mortality, type 2 diabetes mellitus, rheumatological diseases and quality of life impairments are supported by strong evidence. Also, there is strong evidence that sustained viral eradication of HCV can improve important outcomes such as mortality and quality of life.

CONCLUSIONS

The current evidence suggests that HCV has been associated with tremendous clinical, economic and quality of life burden.

Modified hydra bioassay to evaluate the toxicity of multiple mycotoxins and predict the detoxification efficacy of a clay-based sorbent

Food shortages and a lack of food supply regulation in developing countries often leads to chronic exposure of vulnerable populations to hazardous mixtures of mycotoxins, including aflatoxin B(1) (AFB(1)) and fumonisin B(1) (FB(1)). A refined calcium montmorillonite clay [i.e. uniform particle size NovaSil (UPSN)] has been reported to tightly bind these toxins, thereby decreasing bioavailability in humans and animals. Hence, our objectives in the present study were to examine the ability of UPSN to bind mixtures of AFB(1) and FB(1) at gastrointestinally relevant pH in vitro, and to utilize a rapid in vivo bioassay to evaluate AFB(1) and FB(1) toxicity and UPSN efficacy. Isothermal sorption data indicated tight AFB(1) binding to UPSN surfaces at both pH 2.0 and 6.5, but substantially more FB(1) bound at pH 2.0 than 6.5. Site-specific competition occurred between the toxins when exposed to UPSN in combination. Importantly, treatment with UPSN resulted in significant protection to mycotoxin-exposed hydra maintained at pH 6.9-7.0. Hydra were exposed to FB(1), AFB(1) and FB(1) /AFB(1) combinations with and without UPSN. A toxic response over 92 h was rated based on morphology and mortality. Hydra assay results indicated a minimum effective concentration (MEC) of 20 µg ml(-1) for AFB(1), whereas the MEC for FB(1) was not reached. The MEC for co-exposure was 400 µg ml(-1) FB(1) + 10 µg ml(-1) AFB(1). This study demonstrates that UPSN sorbs both mycotoxins tightly at physiologically relevant pH levels, resulting in decreased bioavailability, and that a modified hydra bioassay can be used as an initial screen in vivo to predict efficacy of toxin-binding agents.

Regulation of LKB1 expression by sex hormones in adipocytes

OBJECTIVE

In the adipose tissue, activation of AMP-activated protein kinase (AMPK) by phosphorylation favours local fatty acid oxidation and inhibition of lipogenesis. We have previously shown that the potent androgen dihydrotestosterone (DHT) can inhibit phosphorylation of AMPK in adipose tissue and 3T3-L1 adipocytes in a dose-dependent manner. This negative effect of DHT was reversed by oestrogen treatment. The purpose of this current study was to determine the underlying mechanisms whereby androgens and oestrogens can regulate AMPK phosphorylation in adipocytes, and whether this mechanism is receptor dependent.

RESULTS

Phosphorylation of AMPK was assessed by western blot in cells treated for 24 h with testosterone or DHT (1-1000 nM). Testosterone and DHT significantly inhibited basal phosphorylation of AMPK. Addition of the androgen receptor antagonist Flutamide (1 μM) to the media reversed the negative effect of testosterone and DHT by returning AMPK phosphorylation levels to those of basal. To further dissect the mechanism underlying AMPK inhibition by testosterone or DHT, we examined the mRNA expression of the upstream activator of AMPK, namely LKB1. Testosterone and DHT treatment of murine 3T3-L1 or human SGBS adipocytes for 24 h significantly decreased the mRNA expression of LKB1. In contrast, 17β-estradiol treatment increased LKB1 mRNA, an effect mediated by oestrogen receptor alpha.

CONCLUSION

We conclude that regulation of AMPK phosphorylation by androgens and oestrogens is receptor-dependent, and demonstrate for the first time that LKB1 is regulated by sex hormones in adipocytes.

The influence of induction therapy on graft and patient survival in patients with and without hepatitis C after liver transplantation

We used the United Network for Organ Sharing Database to determine the influence of antibody-based induction therapy on patient and graft survival in orthotopic liver transplant (OLT) recipients with and without hepatitis C (HCV). We identified all initial OLT patients with HCV serology. Patients were divided into four groups: HCV positive without induction (17 362), HCV positive with induction (3479), HCV negative without induction (20 417) and HCV negative with induction (4357). Both HCV positive and negative patients who received induction did better than those who did not. For HCV positive patients, 5-year patient survival was 70.8% versus 68.7% (p = 0.004) and graft survival was 65.2% versus 62.1% (p < 0.001). For HCV negative patients, 5-year patient survival was 78.8% versus 76.7% (p < 0.001) and graft survival was 74.0% versus 70.8% (p < 0.001). On multivariate analysis, induction was associated with improved patient (HR = 0.91: p = 0.024) and graft (HR = 0.88: p < 0.001) survival in HCV positive patients and improved patient (HR = 0.87: p = 0.003) and graft survival (HR = 0.87: p < 0.001) in HCV negative patients. The benefit of induction occurred early and largely dissipated when patients with death within a year were censored. The benefit of induction therapy appeared most pronounced in patients with renal insufficiency or on organ-perfusion support at transplant.

Power-based segmentation of respiratory signals using forward-backward bank filtering

We present an automated method for the segmentation of ribcage and abdominal signals measured by noninvasive respiratory inductance plethysmography (RIP) into quiet breathing and artifact-corrupted segments. This procedure, which involves forward-backward filtering, is applicable to the automated off-line analysis of long records of respiratory signals. Examples of applications include home and sleep laboratory studies of cardiorespiratory data. The new procedure was successfully applied to the segmentation of cardiorespiratory signals acquired post-operatively from infants in the recovery room of the Montreal Children's Hospital (MCH).

Clinical trial: healing of NSAID-associated gastric ulcers in patients continuing NSAID therapy - a randomized study comparing ranitidine with esomeprazole

BACKGROUND

The use of non-steroidal anti-inflammatory drugs (NSAID) is associated with an increased risk of gastric ulcer (GU) development.

METHODS

This multicentre, randomized, double-blind, parallel-group trial compared endoscopic healing rates at 4 and 8 weeks after treatment with oral esomeprazole 40 or 20 mg once daily, or ranitidine 150 mg twice daily, in patients with 1 baseline GU > or = 5 mm but no GUs or duodenal ulcers >25 mm in diameter who received continued cyclooxygenase-2-selective or non-selective NSAID therapies. The primary outcome was the percentage of patients in each treatment group who had no GUs at week 8.

RESULTS

Four hundred and forty patients were randomized to treatment. At week 8, GU healing rates (95% CI) with esomeprazole 40 mg, esomeprazole 20 mg and ranitidine were 85.7 (79.8-91.7)%, 84.8 (78.8-90.8)% and 76.3 (69.2-83.3)%, respectively; between-group differences were not statistically significant. Week-4 GU healing rates were 70.7 (62.9-78.4)% and 72.5 (65.0-79.9)% with esomeprazole 40 and 20 mg, respectively, and were significantly higher (P < 0.01 for both doses) than those with ranitidine [55.4 (47.1-63.7)%].

CONCLUSION

In patients who require continued NSAID therapy, GU healing rates at 8 weeks numerically favoured esomeprazole but were not significantly different from ranitidine.

Detection of movement artifacts in respiratory inductance plethysmography: performance analysis of a Neyman-Pearson energy-based detector

In [3] we developed a method for the automated estimation of the phase relation between thoracic and abdominal signals measured by noninvasive respiratory inductance plethysmography (RIP). In the present paper, we improve on the phase estimator by including an automated procedure for the detection of periods of gross body movements. We assume that the number of sleep obstructive events during periods of gross body movements is zero in probability. We hope that combining the phase estimator with the gross body movement detector should yield improved diagnostic tools for the automated classification of obstructive hypopnea events.

Randomised trial of infant sleep location on the postnatal ward

OBJECTIVE

To determine whether postnatal mother-infant sleep proximity affects breastfeeding initiation and infant safety.

DESIGN

Randomised non-blinded trial analysed by intention to treat.

SETTING

Postnatal wards of the Royal Victoria Hospital (RVI), Newcastle upon Tyne, UK.

PARTICIPANTS

64 newly delivered mother-infant dyads with a prenatal intention to breastfeed (vaginal deliveries, no intramuscular or intravenous opiate analgesics taken in the preceding 24 h).

INTERVENTION

Infants were randomly allocated to one of three sleep conditions: baby in mother's bed with cot-side; baby in side-car crib attached to mother's bed; and baby in stand-alone cot adjacent to mother's bed.

MAIN OUTCOME MEASURES

Breastfeeding frequency and infant safety observed via night-time video recordings.

RESULTS

During standardised 4-h observation periods, bed and side-car crib infants breastfed more frequently than stand-alone cot infants (mean difference (95% confidence interval (CI)): bed v stand-alone cot = 2.56 (0.72 to 4.41); side-car crib v stand-alone cot = 2.52 (0.87 to 4.17); bed v side-car crib = 0.04 (-2.10 to 2.18)). No infant experienced adverse events; however, bed infants were more frequently considered to be in potentially adverse situations (mean difference (95% CI): bed v stand-alone cot = 0.13 (0.03 to 0.23); side-car crib v stand-alone cot = 0.04 (-0.03 to 0.12); bed v side-car crib = 0.09 (-0.03-0.21)). No differences were observed in duration of maternal or infant sleep, frequency or duration of assistance provided by staff, or maternal rating of postnatal satisfaction.

CONCLUSION

Suckling frequency in the early postpartum period is a well-known predictor of successful breastfeeding initiation. Newborn babies sleeping in close proximity to their mothers (bedding-in) facilitates frequent feeding in comparison with rooming-in. None of the three sleep conditions was associated with adverse events, although infrequent, potential risks may have occurred in the bed group. Side-car cribs are effective in enhancing breastfeeding initiation and preserving infant safety in the postnatal ward.

HER2 expression as a potential marker for response to therapy targeted to the EGFR

Since human epidermal growth factor receptor 2 (HER2) is known to participate with the epidermal growth factor receptor (EGFR) in mitogenic signalling, we hypothesised that HER2 overexpression might indicate responsiveness to EGFR targeted therapies. MCF7 breast cancer cells transfected with the HER2 gene were subcloned to establish a set of genetically related cell lines expressing graded levels of HER2 by immunoblot analysis. The subcloned cell lines and parental MCF7 cells were characterised by their growth characteristics, and cell by cell patterns of EGFR, HER2 and HER3 expression as well as levels of phosphorylated mitogen-activated protein kinase (MAPK) and AKT by laser scanning cytometry (LSC). Growth inhibition assays were used to characterise response to EGFR targeted therapy, and to determine the relationship between therapeutic response and levels of tyrosine kinase expression. The levels of growth inhibition of AG1478 and of the AG1478-trastuzumab combinations were correlated with levels of HER2 expression among the different cell lines. Among EGFR, HER2 and HER3, HER2 overexpression was the best single predictive marker, but combinations of two markers provided additional predictive information.

Neutrophils in development of multiple organ failure in sepsis

Multiple organ failure is a major threat to the survival of patients with sepsis and systemic inflammation. In the UK and in the USA, mortality rates are currently comparable with and projected to exceed those from myocardial infarction. The immune system combats microbial infections but, in severe sepsis, its untoward activity seems to contribute to organ dysfunction. In this Review we propose that an inappropriate activation and positioning of neutrophils within the microvasculature contributes to the pathological manifestations of multiple organ failure. We further suggest that targeting neutrophils and their interactions with blood vessel walls could be a worthwhile therapeutic strategy for sepsis.

Human chorionic gonadotropin-dependent induction of an equine aldo-keto reductase (AKR1C23) with 20alpha-hydroxysteroid dehydrogenase activity during follicular luteinization in vivo

Aldo-keto reductases (AKRs) are multifunctional enzymes capable of acting on a wide variety of substrates, including sex steroids. AKRs having 20alpha-hydroxysteroid dehydrogenase (20alpha-HSD) activity can reduce progesterone to 20alpha-hydroxy-4-pregnen-3-one (20alpha-DHP), a metabolite with lower affinity for the progesterone receptor. The objective of this study was to investigate the regulation of equine AKR1C23 during human chorionic gonadotropin (hCG)-induced ovulation/luteinization. The equine AKR1C23 cDNA was cloned and shown to encode a 322 amino acid protein that is conserved (71-81% identity) when compared with mammalian orthologs. RT-PCR/Southern blotting analyses were performed to study the regulation of AKR1C23 transcripts in equine preovulatory follicles isolated between 0 and 39 h after hCG treatment (ovulation occurring 39-42 h post-hCG). Results showed the presence of low AKR1C23 expression before hCG treatment, but a marked increase was observed in follicles obtained 12 h after hCG (P<0.05). Analyses of isolated preparations of granulosa and theca interna cells identified low mRNA expression in both cell types prior to hCG treatment, with granulosa cells clearly being the predominant site of follicular AKR1C23 mRNA induction. A specific polyclonal antibody was raised against a fragment of the equine protein and immunoblotting analyses showed an increase in AKR1C23 protein in granulosa cell extracts when comparing follicles isolated at 36 h post-hCG vs those collected prior to treatment, in keeping with mRNA results. Immunohistochemical data confirmed the induction of the enzyme in follicular cells after hCG treatment. The enzyme was tested for 20alpha-HSD activity and was shown to exhibit a K(M) of 3.12 microM, and a V(max) of 0.86 pmol/min per 10 microg protein towards progesterone. The levels of 20alpha-DHP measured in follicular fluid reflected this activity. Collectively, these results demonstrate for the first time that the gonadotropin-dependent induction of follicular luteinization is accompanied by an increase in AKR1C23 expression. Considering the 20alpha-HSD activity of AKR1C23, its regulated expression in luteinizing preovulatory follicles may provide a biochemical basis for the increase in ovarian 20alpha-DHP observed during gonadotropin-induced luteinization/ovulation. (The nucleotide sequence reported in this paper has been submitted to GenBank with accession number AY955082.).

Sleep and breathing on the first night after adenotonsillectomy for obstructive sleep apnea

Adenotonsillectomy (T&A) has established effectiveness for the treatment of obstructive sleep apnea (OSA). However, more than 20% of children with OSA have respiratory compromise requiring medical intervention in the postoperative period. The reasons for this complication are not well-defined. We aimed to compare the nature and severity of sleep-disordered breathing in children with mild and severe OSA on the first night following adenotonsillectomy. Ten children were classified into groups of mild and severe OSA, based on preoperative testing. On the first night after T&A, they underwent polysomnography, including electroencephalograph, submental electromyography, bilateral electro-oculograms, monitoring of respiratory movements, heart rate, ECG, and oxygen saturation. Sleep-disordered breathing was assessed by the apnea-hypopnea index, the SaO(2) nadir, and the desaturation index, including dips in saturation below 90% (DI(90)). Sleep quality was assessed by sleep efficiency, time spent in each sleep state, and respiratory arousal index. Obstructive events occurred postoperatively in all children, but were more frequent in those with severe OSA preoperatively: the median (interquartile range) mixed/obstructive apnea/hypopnea indicies were 6.9 (2.2-9.8) events/hr and 21.5 (15.1-112.1) events/hr for the mild OSA group and the severe OSA group, respectively (P = 0.009). Obstructive events were the major cause of desaturation during sleep postoperatively. Sleep quality was severely disrupted in both groups, with reductions in both slow-wave sleep and rapid eye movement sleep. In conclusion, despite removal of obstructing lymphoid tissue, upper airway obstruction occurred on the first postoperative night in children with OSA. This study is the first to demonstrate the mechanism of respiratory compromise after adenotonsillectomy, a common postoperative complication in children with severe OSA.

Modulation of in vivo 3-deoxyglucosone levels

Fructoselysine 3-phosphate is synthesized in vivo by the recently discovered fructoseamine-3-kinase (F3K) from fructoselysine and ATP and decomposes to lysine, Pi and 3-deoxyglucosone (3DG). This pathway appears to dominate 3DG production in vivo, making it possible to modulate 3DG levels by stimulating or inhibiting the reaction. Present inhibitors are non-reacting substrate analogues with relatively high Ki values and can inhibit F3K sufficiently in vivo to reduce 3DG in diabetic rat plasma by approx. 50%. Stimulation of the F3K pathway by feeding glycated casein causes an increase of 10–20-fold in plasma levels of 3DG and 3-fold in kidney tubules. Consequences of this increase were studied in two systems: the Eker rat, a model of susceptible kidney tubules; and birth rates in two rat strains. In both cases substantial pathological effects were observed. In the Eker rats, an approx. 3-fold increase in kidney lesions was observed (P<0.00001). In both Fischer 344 and Sprague–Dawley rats, birth rates were reduced by 56% (P<0.0001) and 12% (P<0.015) respectively. These results suggest that inhibition of F3K is a promising new therapeutic target for diabetic complications, as well as other 3DG-dependent pathologies.

Twists and turns: a tale of two shikimate-pathway enzymes

We are studying two enzymes from the shikimate pathway, dehydroquinate synthase (DHQS) and 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS). Both enzymes have been the subject of numerous studies to elucidate their reaction mechanisms. Crystal structures of DHQS and EPSPS in the presence and absence of substrates, cofactors and/or inhibitors are now available. These structures reveal movements of domains, rearrangements of loops and changes in side-chain positions necessary for the formation of a catalytically competent active site. The potential for using complementary small-angle X-ray scattering (SAXS) studies to confirm the presence of these structural differences in solution has also been explored. Comparative analysis of crystal structures, in the presence and absence of ligands, has revealed structural features critical for substrate-binding and catalysis. We have also analysed these structures by generating GRID energy maps to detect favourable binding sites. The combination of X-ray crystallography, SAXS and computational techniques provides an enhanced analysis of structural features important for the function of these complex enzymes.

Yersinia pestis and plague

Yersinia pestis is the aetiological agent of plague, a disease of humans that has potentially devastating consequences. Evidence indicates that Y. pestis evolved from Yersinia pseudotuberculosis, an enteric pathogen that normally causes a relatively mild disease. Although Y. pestis is considered to be an obligate pathogen, the lifestyle of this organism is surprisingly complex. The bacteria are normally transmitted to humans from a flea vector, and Y. pestis has a number of mechanisms which allow survival in the flea. Initially, the bacteria have an intracellular lifestyle in the mammalian host, surviving in macrophages. Later, the bacteria adopt an extracellular lifestyle. These different interactions with different host cell types are regulated by a number of systems, which are not well characterized. The availability of the genome sequence for this pathogen should now allow a systematic dissection of these regulatory systems.

Differential expression of beta1 and beta2 integrins and L-selectin on CD4+ and CD8+ T lymphocytes in human blood: comparative analysis between isolated cells, whole blood samples and cryopreserved preparations

Flow cytometric analysis was used to compare the expression of adhesion molecules on human CD4+ and CD8+ T lymphocytes in isolated blood mononuclear cells (MNCs) in whole blood samples and in cryopreserved MNC preparations. Examination of MNCs revealed that the CD11b and CD11c components of the beta2 integrins were preferentially expressed on CD8+ T cells, whereas CD62L was present on more CD4+ T cells. All CD4+ and CD8+ T lymphocytes were positive for CD11a but the CD8+ population had a higher intensity of expression of CD11a and also CD11b. Virtually identical results were obtained with T cells in whole blood samples. In relation to the beta1 integrins, the only difference between isolated CD4+ and CD8+ T cells was that the latter subset had a greater proportion of cells bearing CD49d. The naive cell marker CD45RA was present on the majority of CD8+ T cells whereas CD45RA and the memory marker CD45RO were evenly distributed within the CD4+ T cell subset. Although cryopreservation of lymphocytes did not modify the expression of beta1 and beta2 integrins it produced a marked reduction in the percentage of CD4+ and CD8+ T cells bearing CD62L. With regard to endothelial interactions, it appears that cryopreserved lymphocytes are suitable for inclusion in studies of integrin-mediated adhesion but not for those relating to tethering or recognition of addressins on high endothelial venules. Differences in adhesion molecule expression between CD4+ and CD8+ T lymphocytes could underlie the selective extravasation of these subsets into sites of infection and inflammation.

Automated analysis of paradoxical ribcage motion during sleep in infants

Identification of thoracoabdominal asynchrony (TAS) during breathing is currently detected by visual coding of records of ribcage (RC) and abdominal (AB) movements. There is thus a need to automate this process in order to save time and improve TAS detection accuracy. We studied 15 infants of 39-49 weeks postconceptional age. RC and AB signals were recorded continuously by inductance plethysmography for 4-24 hr immediately after herniorraphy. In our novel analysis approach, the records were divided into 10 sec epochs, and the equation RC = alphaAB + beta was fit to each epoch, using recursive linear regression with an exponential memory time constant of 1 and 2 sec. This yielded 10 sec signals for alpha corresponding to each epoch. The fraction of time that each alpha signal was positive was taken as a measure of synchrony between RC and AB for that epoch, while asynchrony was indicated by the fraction of time the signal was negative. We also assessed synchrony and asynchrony using a conventional measure known as thoracic delay (TD), which is based on the degree to which the peaks in RC and AB are coincident in time. Using TD as the basis of comparison, we found that our new recursive least squares method gave a positive predictive value of 99%. We conclude that our recursive least squares method is able to accurately identify portions of the RC and AB records that correspond to TAS, and we speculate that it may be useful in automating detection of TAS.

Factors modifying the migration of lymphocytes across the blood-brain barrier

Characterising the factors that control the entry of leucocytes into tissue in response to inflammatory or microbial insult continues to generate considerable interest. Of all the tissues studied it is probably that of the CNS which is the most fascinating because of the specialised properties of its blood vessel walls, which constitute the blood-brain barrier (BBB). In health, very few leucocytes penetrate the BBB but in disorders such as MS the barrier becomes compromised with the result that there is an intense infiltration of the CNS by T lymphocytes whose subsequent activity appears to underlie the onset and progression of disease. The purpose of this article is to summarise and assess recent literature pertaining to how lymphocytes bind to cerebral endothelial cells, migrate across the blood vessel walls and enter the CNS parenchyma. Particular emphasis is devoted to the cellular and molecular aspects of these events and addressing the questions of whether certain subsets of circulating T lymphocytes are more favourably disposed than others to CNS infiltration and whether entry is dependent upon the initial expression of distinct groups of adhesion molecules and upon the generation of chemotactic factors. This article also focuses upon identifying the key stages of lymphocyte migration across the BBB and their susceptibility to antagonism by therapeutic agents. It is intended that the review will provide a useful source of information and offer additional insights into the mechanisms controlling lymphocyte passage across the BBB during pathological disturbance.

Failure of single-toxin assays to detect clostridium difficile infection in pediatric inflammatory bowel disease

OBJECTIVES

The aims of this retrospective study were 1) to determine the ability of single-toxin assays for Clostridium difficile to detect infection among pediatric patients with inflammatory bowel disease (IBD) and 2) to determine the toxin assays routinely used by pediatric tertiary care hospitals in the United States.

METHODS

Stool specimens from patients with IBD (submitted from January, 1996, to August, 1999) were evaluated for the presence of C. difficile toxin A and toxin B. Toxin profile (toxin A alone, toxin B alone, toxin A and B together) was compared in positive specimens. A phone interview was conducted with representatives from laboratories in 22 pediatric hospitals to investigate which toxin assays were routinely used.

RESULTS

A total of 697 specimens were submitted from 284 IBD patients. In all, 81 IBD patients (28.5%) had at least one documented infection. Toxin A assay failed to identify 41.5% of C. difficile infections. Toxin B assay failed to detect 34.9% of C. difficile infections. Toxin profile changed in 55% of patients with multiple infections. Of the hospitals surveyed, 59% did not test for both toxins.

CONCLUSIONS

Single-toxin assays for C. difficile fail to detect a significant percentage of infections. The toxins identified during one infection are not predictive of the toxins identified in subsequent infections. Despite this, many pediatric hospitals do not routinely use both toxin assays to diagnose C. difficile infection. When infection is suspected, assays for C. difficile toxin A and toxin B should be requested.

Increased distribution and expression of CD64 on blood polymorphonuclear cells from patients with the systemic inflammatory response syndrome (SIRS)

Evidence is growing to suggest that the multiple organ damage of the systemic inflammatory response syndrome (SIRS) arises from the untoward activity of blood polymorphonuclear cells (PMNs), which upon activation acquire the IgG high affinity receptor, CD64. In the current study, flow cytometry was used to assess the prevalence of CD64-bearing PMNs and the intensity of expression of CD64 in whole blood samples from 32 SIRS patients, 11 healthy normal subjects and from eight non-SIRS patients in the intensive care unit (ICU). The percentage of PMNs expressing CD64 was higher in SIRS patients (mean 65%) than in non-SIRS patients (mean 42%; P < 0.02) and in healthy controls (mean 19%; P < 0.001) and was particularly evident in patients with SIRS and sepsis (mean 71%; P < 0.02) as opposed to SIRS alone (mean 55%). There were more CD64 molecules expressed on PMNs from patients with SIRS (median 1331 molecules/cell) in comparison with PMNs from healthy subjects (median 678 molecules/cell; P < 0.01). The highest intensity of CD64 expression was associated with PMNs from patients with both SIRS and sepsis. Functional studies revealed that the supranormal binding of PMNs from patients with SIRS to endothelial monolayers treated with TNFalpha was impeded by anti-CD64 antibodies (mean 24% inhibition; P < 0.01). Monitoring the distribution of CD64+ PMNs and their level of CD64 expression could be of assistance in the rapid discrimination of patients with SIRS from other ICU patients and in the identification of PMNs which are likely to participate in the pathological manifestations of the disease.

Distinctive patterns of Her-2/neu, c-myc, and cyclin D1 gene amplification by fluorescence in situ hybridization in primary human breast cancers

BACKGROUND

Human solid tumors undergo clonal evolution as they progress, but evidence for specific sequences of genetic changes that occur in individual tumors and are recapitulated in other tumors is difficult to obtain.

METHODS

Patterns of amplification of Her-2/neu, c-myc, and cyclin D1 were determined by fluorescence in situ hybridization (FISH) in relation to the presence of p53 dysfunction and ploidy in 60 primary human breast cancers.

RESULTS

We show that there are clusters of genophenotypic abnormalities that distinguish lobular breast cancers from nonlobular tumors; that cyclin D1 amplification occurs prior to the divergence of lobular breast cancers from nonlobular cancers; that p53 dysfunction, Her-2/neu amplification, and c-myc amplification are characteristic features of nonlobular breast cancers, but not of lobular breast cancers; and that the frequencies of amplification of all three oncogenes examined increase progressively with increasing aneuploidy, but that each gene exhibits a different profile of increasing amplification in relation to tumor progression. Early amplification of c-myc appears to be an especially prominent feature of hypertetraploid/hypertetrasomic tumors.

CONCLUSIONS

The data suggest that in tumors containing multiple abnormalities, these abnormalities often accumulate in the same cells within each tumor. Furthermore, the same patterns of accumulation of multiple genophenotypic abnormalities are recapitulated in different tumors.

Identification from a bitemark in a wad of chewing gum

A wad of used chewing gum recovered from the scene of a burglary contained impressions of human teeth. Casts of these impressions displayed unique morphological characteristics which were found to show concordance with corresponding features present on casts of the posterior teeth of a suspect.

The use of hepatitis C viral RNA levels in liver tissue to distinguish rejection from recurrent hepatitis C

Persistence of hepatitis C virus (HCV) after orthotopic liver transplantation is almost universal in HCV-infected patients. Histological examination of liver biopsy specimens can be variable in distinguishing between recurrent hepatitis C and acute cellular rejection. The purpose of this study is to determine whether hepatic HCV RNA levels can be used to distinguish rejection from recurrent HCV by determining whether hepatic HCV RNA levels correlate with histological characteristics and clinical course. Seventy-two biopsy specimens were evaluated from 36 liver transplant recipients with HCV and elevated liver-related enzyme levels. Based on histological findings and clinical response to therapy, patients were defined as belonging to 1 of 5 groups: (1) definite rejection, (2) probable rejection, (3) indeterminate findings, (4) probable HCV, and (5) definite HCV. Hepatic HCV RNA was quantified using the Amplicor Monitor assay (Roche Diagnostic Systems Inc, Branchburg, NJ). There was a difference across groups in HCV RNA levels (P =.046). The median HCV RNA level was 10,695 copies/mg of tissue DNA in the definite-HCV group compared with 1,024 copies/mg of tissue DNA in the definite-rejection group. Using pairwise comparisons, significant differences were found between definite HCV and definite rejection, probable HCV and definite rejection, probable HCV and probable rejection, and probable HCV and indeterminate. Our findings support the following conclusions. (1) In liver transplant recipients, hepatic HCV RNA levels are statistically greater in patients with recurrent HCV than rejection, although there is considerable overlap between groups. (2) Patients with low HCV RNA levels were unlikely to have recurrent HCV. (3) Patients with minimal and indeterminate findings on biopsy (group 3) had low HCV RNA levels.

Liver transplantation

Continued discussion over organ allocation and distribution remained a focal point in the field of liver transplantation in the year 2000. Despite the ongoing debate, no significant changes were implemented in the current allocation system. By far, the most widely discussed topic in liver transplantation this year was live donor adult-to-adult liver transplantation. Several authors reported on their initial experience, with both recipient and donor outcomes appearing excellent. As the number of transplant centers performing this procedure increases we look forward to further studies regarding the safety and long-term outcome of this innovative procedure. Studies on viral hepatitis after liver transplantation again focused on the problem of recurrent hepatitis B and hepatitis C. Several small studies found benefit in patients with hepatitis B treated with intramuscular hepatitis B immunoglobulin and lamivudine after transplantation. Although breakthrough replication remains a problem in some patients, these studies offer hope that combination therapy for hepatitis B may provide improved long-term graft survival in these patients. In patients with hepatitis C, several studies focused on identifying risk factors to predict graft recurrence of the virus after liver transplantation. Both cellular rejection and level of viral replication may be important predictors of recurrent hepatitis C virus in the graft. Early treatment reports using interferon and ribavirin suggest that some patients may have a viral response during therapy; however, it is short lived, and tolerance of medication is difficult. Certainly, we look forward to further studies looking at means of prevention and treatment of viral hepatitis in patients undergoing liver transplantation.