Seroprevalence of antibody to pandemic influenza A (H1N1) 2009 among healthcare workers after the first wave in Hong Kong

During the first wave of an influenza pandemic prior to the availability of an effective vaccine, healthcare workers (HCWs) may be at particular risk of infection with the novel influenza strain. We conducted a cross-sectional study of the prevalence of antibody to pandemic influenza A (H1N1) 2009 (pH1N1) among HCWs in Hong Kong in February–March 2010 following the first pandemic wave. Sera collected from HCWs were tested for antibody to pH1N1 influenza virus by viral neutralisation (VN). We assessed factors associated with higher antibody titres, and we compared antibody titres in HCWs with those in a separate community study. In total we enrolled 703 HCWs. Among 599 HCWs who did not report receipt of pH1N1 vaccine, 12% had antibody titre ≥1:40 by VN. There were no significant differences in the age-specific proportions of unvaccinated HCWs with antibody titre ≥1:40 compared with the general community following the first wave of pH1N1. Under good adherence to infection control guidelines, potential occupational exposures in the hospital setting did not appear to be associated with any substantial excess risk of pH1N1 infection in HCWs. Most HCWs had low antibody titres following the first pandemic wave.

Imprinting in the schizophrenia candidate gene GABRB2

Imprinting, characterized by unequal expression of the offspring's genes in a parent-of-origin dependent manner, has been functionally implicated in brain development and in psychiatric disorders. In this study, unambiguous distortion in paternal but not maternal transmission of the disease-associated single-nucleotide polymorphism (SNP) rs6556547 (T/G) clearly indicated the presence of parent-of-origin effect (POE) in the GABAA receptor β2 subunit gene (GABRB2). ‘Flipping’ of allelic mRNA expression in heterozygotes of SNP rs2229944 (C/T) and the observed two-tiered distribution of mRNA expression levels in heterozygotes of the disease-associated SNP rs1816071 (G/A) furnished important support for the occurrence of imprinting at GABRB2. Imprinting in effect introduced heterozygotes from different parents-of-origin endowed with dissimilar mRNA expression capabilities. The deficit of upper-tiered expressions accounted for the lowered mRNA expression levels in the schizophrenic heterozygotes. This pointed to the necessity of differentiating between two kinds of heterozygotes of different parental origins in disease association studies on GABRB2. Bisulfite sequencing revealed hypermethylation in the neighborhood of SNP rs1816071, and methylation differences between controls and schizophrenia patients. Notably, allele-specific methylation was observed at the disease-associated SNPs rs6556547 and rs1816071. These findings raised the possibility that CpG methylation status of these sites could have an impact on the expression of GABRB2 and the risk of schizophrenia. Furthermore, the occurrence of imprinting and allele-specific methylation in the schizophrenia candidate gene GABRB2 was compatible with the epigenetic hypothesis for schizophrenia pathophysiology, thereby calling for the need to explore the role of epigenetic factors in mediating susceptibility to schizophrenia.

Potential predictors of pancreatic cancer: A population-based screen

164

Background: Pancreatic cancer (PC) is the fourth leading cause of cancer-related death in the U.S. Unfortunately, PC is usually diagnosed at late stages. We hypothesized that certain diagnoses may precede PC diagnosis and assist in early identification of pancreatic cancer patients.

Methods: SEER-Medicare 1991-2005 was used to identify PC patients. PC and prePC diagnoses were identified using ICD9 codes. We then examined pre-pancreatic cancer (prePC) diagnoses and compared the frequency of those diagnoses by PC stage at time of cancer diagnosis. Stepwise logistic regression was used to assess potential PrePC diagnoses. Risk factors were compared by stage at diagnosis using Kruskal-Wallis test, stratified univariate analysis and logistic regression. Time to diagnosis was calculated for each PrePC diagnosis.

Results: 19,801 PC patients were identified. Significant (p<0.05) prePC diagnoses included acute pancreatitis, chronic pancreatitis, cyst/pseudocyst, other pancreatic disease, bile duct obstruction, diabetes, weight loss, jaundice, abdominal pain, hepatomegaly. Median time (months) and interquartile range percentiles (25th-75th) before PC diagnosis were as follows: acute pancreatitis 0.97 (0.33-8.6), chronic pancreatitis 1.56 (0.37-11), cyst/pseudocyst 0.83 (0.3-3.5), other pancreatic disease 0.47 (0.2-1.2), bile duct obstruction 0.4 (0.17- 0.83), diabetes 30.6 (11.3-59.8), weight loss 1.16 (0.43-5.1), jaundice 0.43 (0.2-0.8), abdominal pain 16 (1.07-55.5), hepatomegaly 1.06 (0.33-1.07). Patients diagnosed at AJCC stage 0 had a mean of 3.53 prePC diagnoses (±SD 1.42); stage IA, 2.80 (1.68); stage IB, 2.42 (1.57); stage IIA, 2.44 (1.63); stage IIB, 2.46 (1.64); stage III, 2.33 (1.59); and Stage IV, 1.79 (1.40) (p<0.001).

Conclusions: PC patients who presented at later stages were less likely to have prePC claims identified prior to PC diagnosis compared with patients diagnosed at earlier stages. This analysis of potential prePC diagnoses suggests that access to care and earlier identification of PC related conditions may factor into the stage at which this lethal disease is identified. Further studies need to be conducted to identify and analyze additional predictors of PC and better screen individuals at risk.

No significant financial relationships to disclose.

Minimally invasive surgery for resectable pancreatic cancer in the United States: From staging tool to treatment strategy

243

Background: Debate exists regarding the use of laparoscopy in pancreatic malignancy. The goal of this study was to examine recent laparoscopy use in pancreatic resections for cancer in the US. We hypothesized that there would be two noticeable trends in the use of laparoscopy – the first reflecting staging laparoscopy, the second associated with advancement of laparoscopic pancreatectomy.

Methods: The Nationwide Inpatient Sample (NIS), 1998-2007, was used to identify patients ≥ 18 years old with pancreatic cancer who underwent pancreatic resection with or without associated laparoscopy. Patterns of laparoscopy use and correlated outcomes were examined.

Results: Among 47599 patients (nationally weighted) who underwent resection for pancreatic cancer, 2640 (5.5%) had procedures that included laparoscopy. Yearly trend analyses demonstrated a peak in laparoscopy in 2003 followed by decreased use, then steady increase after 2005. Laparoscopy at time of resection was not significantly associated with decreased complications (p=0.09), but was associated with lower mortality compared to open resection alone (3.2% vs. 5.9%, p = 0.008). On multivariate analysis, independent predictors of increased complications included older age, male sex, higher comorbidity (Charlson) score, urban location, and non-teaching hospital. For increased risk of death, predictors were older age, male sex, Charlson >2, non-teaching hospital, and non-use of laparoscopy.

Conclusions: Trends in the use of laparoscopy during pancreatic resections for cancer suggest initial increased use in the early 2000's following published staging recommendations, with a subsequent decrease contemporaneous with improving imaging techniques. A recent upward trend is likely associated with increased attempts at minimally-invasive resection. The use of laparoscopy is not associated with any difference in complication rate following surgery and is associated with improved perioperative survival. The effects of patient factors, selection, and volume status on minimally invasive pancreatectomy outcomes warrant further investigation.

No significant financial relationships to disclose.

Nationwide trends in diagnosis and outcomes of gastrointestinal stromal tumors in the era of targeted therapy

121

Background: Gastrointestinal stromal tumors (GISTs) have historically been inconsistently categorized in tumor registries. Discovery of c-kit expression in 1998 allowed for more precise diagnosis, and use of tyrosine kinase inhibitors for GIST in 2000 marked a new era in management. We examined nationwide trends in the diagnosis, management, and outcomes of GIST in this post-imatinib era.

Methods: Patients ≥ 18 years old with GIST were identified in the SEER database 1998-2007, using the GIST-specific ICD-O-3 code. After a period of steady increase, incidence stabilized after 2001. Trends from 2002 to 2007 were examined. Univariate and multivariate analyses were performed. This cohort was further divided into 2002-2004 and 2005-2007 for survival analysis by Kaplan-Meier methods and Cox proportional-hazard ratios.

Results: 3,604 patients were identified. There was a dramatic increase in diagnoses from 1998 to 2001 (109 to 376 cases, p < 0.0001), but no significant change from 2002 to 2007 (p = 0.572). During this period of stable incidence (2002-2007), the proportion of patients recommended for surgery continued to decrease (85.2% to 80.1%, p = 0.0006), while utilization of radiation (which dropped to 1.1% by 2001) remained relatively constant (p = 0.101). Anatomic distribution remained stable (p = 0.529), with stomach (52.9%) and small bowel (29.3%) predominating. There was also no change in stage distribution (p = 0.811). Late stage, black race, and advanced age were predictive of not receiving resection. Female sex, younger age, local disease, later year of diagnosis, and resection were associated with lower risk of death. Survival for patients diagnosed in 2005-2007 improved over 2002-2004 for both unresected (p = 0.027) and resected (p = 0.0998) groups. Resection was an independent predictor of survival in both periods (p < 0.0001).

Conclusions: Incidence of GIST as identified in the SEER database has stabilized 2002-2007, likely reflecting more accurate diagnosis. Survival for both resected and unresected patients has improved since the introduction of imatinib, and continues upward. These population-level findings confirm the significant benefit of surgical therapy beyond clinical trials.

No significant financial relationships to disclose.

Diagnostic ultrasound patterns of parotid glands in human immunodeficiency virus-positive patients in Mulago, Uganda

OBJECTIVES

The purpose of this study was to determine sonographically, in parotid glands of human immunodeficiency virus-positive patients, the condition of glands with or without enlargement, and propose a classification system for the patterns observed using diagnostic ultrasound imaging.

METHODS

In this prospective clinical study, ultrasound scans were performed on 200 patients aged 4-62 years at Mulago Hospital, Uganda.

RESULTS

There were four main distinct ultrasound pathological patterns in the parotids, i.e. lymphocytic aggregations (LAs), lymphoepithelial cysts (LECs), fatty infiltration (FI) and lymphadenopathy only. There were additional subdivisions depending on the presence of echogenic foci and intraparotid lymphadenopathy. Of those patients (n = 64) without parotid enlargement, only 8% showed normal ultrasound features, whereas 34% showed LECs and 31% showed LAs. Of those (n = 136) with parotid enlargement, 46% showed LECs, 23% showed FI and 15% showed LAs. The overall prevalence of LECs in the study sample was 42%. LECs were multiple, mainly between 7 mm and 12 mm in diameter and 26% showed internal echogenic foci either mobile or stationary. In contrast, LAs tended to be ill-defined, less than 5 mm and were not associated with posterior acoustic enhancement. Features differentiating LAs from LECs have not been previously described. Parotid FI (lipodystrophy) was noted in patients on highly active antiretroviral therapy, who showed lesser prevalence of LECs after 12 months of treatment.

CONCLUSIONS

Our study of 200 patients is probably the largest such study in the English language literature. The wide spectrum of diagnostic ultrasound patterns was categorized into four main groups (ten subgroups).

Radiation dose measurements for personnel performing 90Y-ibritumomab tiuxetan administration: a comparison between two injection methods for dose reduction

The purpose of this study was to directly measure, using thermoluminescent dosimeters, the radiation doses received by radiation team members performing (90)Y-ibritumomab tiuxetan administration. The occupational doses associated with two injection methods for patient administration - an automatic syringe driver and an injection box - were compared. The associated risks, namely cancer induction and hereditary effect, were also estimated from the results and compared with risk factors recommended by the International Commission on Radiological Protection publication 103. The results showed that the doses received by the index and thumb of the right hand and the index finger of the left hand of the radiation oncologist were significantly reduced by using the injection box method. The difference in the dose received by the medical physicist using the two methods was not statistically significant. It was observed that three pairs of latex gloves could further reduce the dose to the hands. The radiological risks of cancer induction and hereditary effect were negligible: of the order of 10(-6) and 10(-7) per (90)Y-ibritumomab tiuxetan administration, respectively, for both methods. However, the results of our study also showed that it would be possible in a busy centre for pregnant women to receive a dose of (90)Y-ibritumomab tiuxetan that exceeds the recommended annual dose limit for the surface of the abdomen.

Transforming growth factor-beta1 is the predominant isoform required for breast cancer cell outgrowth in bone

Transforming growth factor (TGF)-beta signaling is a potent modulator of the invasive and metastatic behavior of breast cancer cells. Indeed, breast tumor responsiveness to TGF-beta is important for the development of osteolytic bone metastases. However, the specific TGF-beta isoforms that promote breast cancer outgrowth in bone is unknown. We demonstrate that expression of a TGF-beta ligand trap, which neutralizes TGF-beta1 and TGF-beta3, in MDA-MB-231 breast cancer cells diminished their outgrowth in bone and reduced the severity of osteolytic lesion formation when compared with controls. We further show that a reduction or loss of TGF-beta1 expression within the bone microenvironment of TGF-beta1+/- and TGF-beta1-/- mice significantly reduced the incidence of breast tumor outgrowth compared with wild-type animals. Interestingly, those tumors capable of growing within the tibiae of TGF-beta1-deficient mice had upregulated expression of all three TGF-beta isoforms. Finally, breast cancer cells expressing the TGF-beta ligand trap showed a pronounced reduction in their ability to form osteolytic lesions when injected into the tibiae of TGF-beta1+/- mice. Thus, our studies show that both host- and tumor-derived TGF-beta expression plays a critical role during the establishment and outgrowth of breast cancer cells in bone.

Amyloid load in Parkinson's disease dementia and Lewy body dementia measured with [11C]PIB positron emission tomography

BACKGROUND

Neuropathological studies have reported varying amounts of amyloid pathology in dementia with Lewy bodies (DLB) and Parkinson's disease dementia (PDD). [11C]PIB positron emission tomography (PET) is a marker of brain amyloid deposition. The aim of this study was to quantify in vivo amyloid load in DLB and PDD compared with control subjects and subjects with Parkinson's disease (PD) without dementia.

METHODS

13 DLB, 12 PDD, 10 PD subjects and 41 age matched controls (55-82 years) were recruited. Each subject underwent clinical evaluation, neuropsychological assessment, T1 and T2 MRI, and [11C]PIB PET. The amyloid load was estimated from 60-90' target region:cerebellar [11C]PIB uptake ratios. Object maps were created by segmenting individual MRIs and convolving them with a probabilistic atlas. Cortical [11C]PIB uptake was assessed by region of interest analysis.

RESULTS

The DLB cohort showed a significant increase in mean brain [11C]PIB uptake and individually 11 of the 13 subjects with DLB had a significantly increased amyloid load. In contrast, mean [11C]PIB uptake was normal for the PDD group although two of 12 patients with PDD individually showed a raised amyloid load. Where significant increases in [11C]PIB uptake were found, it was increased in cortical association areas, cingulate and striatum. None of the subjects with PD showed significantly raised cortical [11C]PIB uptake.

CONCLUSION

This study suggests that amyloid load is significantly raised in over 80% of subjects with DLB, while amyloid pathology is infrequent in PDD. These in vivo PET findings suggest that the presence of amyloid in DLB could contribute to the rapid progression of dementia in this condition and that anti-amyloid strategies may be relevant.

Asia Pacific consensus recommendations for colorectal cancer screening

Colorectal cancer (CRC) is rapidly increasing in Asia, but screening guidelines are lacking. Through reviewing the literature and regional data, and using the modified Delphi process, the Asia Pacific Working Group on Colorectal Cancer and international experts launch consensus recommendations aiming to improve the awareness of healthcare providers of the changing epidemiology and screening tests available. The incidence, anatomical distribution and mortality of CRC among Asian populations are not different compared with Western countries. There is a trend of proximal migration of colonic polyps. Flat or depressed lesions are not uncommon. Screening for CRC should be started at the age of 50 years. Male gender, smoking, obesity and family history are risk factors for colorectal neoplasia. Faecal occult blood test (FOBT, guaiac-based and immunochemical tests), flexible sigmoidoscopy and colonoscopy are recommended for CRC screening. Double-contrast barium enema and CT colonography are not preferred. In resource-limited countries, FOBT is the first choice for CRC screening. Polyps 5-9 mm in diameter should be removed endoscopically and, following a negative colonoscopy, a repeat examination should be performed in 10 years. Screening for CRC should be a national health priority in most Asian countries. Studies on barriers to CRC screening, education for the public and engagement of primary care physicians should be undertaken. There is no consensus on whether nurses should be trained to perform endoscopic procedures for screening of colorectal neoplasia.

Quantitative evaluation of motor functional recovery process in chronic stroke patients during robot-assisted wrist training

This study was to investigate the motor functional recovery process in chronic stroke during robot-assisted wrist training. Fifteen subjects with chronic upper extremity paresis after stroke attended a 20-session wrist tracking training using an interactive rehabilitation robot. Electromyographic (EMG) parameters, i.e., EMG activation levels of four muscles: biceps brachii (BIC), triceps brachii (TRI, lateral head), flexor carpiradialis (FCR), and extensor carpiradialis (ECR) and their co-contraction indexes (CI) were used to monitor the neuromuscular changes during the training course. The EMG activation levels of the FCR (11.1% of decrease from the initial), BIC (17.1% of decrease from the initial), and ECR (29.4% of decrease from the initial) muscles decreased significantly during the training (P<0.05). Such decrease was associated with decreased Modified Ashworth Scores for both the wrist and elbow joints (P<0.05). Significant decrease (P<0.05) was also found in CIs of muscle pairs, BIC&TRI (21% of decrease from the initial), FCR&BIC (11.3% of decrease from the initial), ECR&BIC (49.3% of decrease from the initial). The decreased CIs related to the BIC muscle were mainly caused by the reduction in the BIC EMG activation level, suggesting a better isolation of the wrist movements from the elbow motions. The decreased CI of ECR& FCR in the later training sessions (P<0.05) was due to the reduced co-contraction phase of the antagonist muscle pair in the tracking tasks. Significant improvements (P<0.05) were also found in motor outcomes related to the shoulder/elbow and wrist/hand scores assessed by the Fugl-Meyer assessment before and after the training. According to the evolution of the EMG parameters along the training course, further motor improvements could be obtained by providing more training sessions, since the decreases of the EMG parameters did not reach a steady state before the end of the training. The results in this study provided an objective and quantitative EMG measure to describe the motor recovery process during poststroke robot-assisted wrist for the further understanding on the neuromuscular mechanism associated with the recovery.

Abeta deposits in older non-demented individuals with cognitive decline are indicative of preclinical Alzheimer's disease

Approximately 30% of healthy persons aged over 75 years show Abeta deposition at autopsy. It is postulated that this represents preclinical Alzheimer's disease (AD). We evaluated the relationship between Abeta burden as assessed by PiB PET and cognitive decline in a well-characterized, non-demented, elderly cohort. PiB PET studies and cognitive tests were performed on 34 elderly participants (age 73+/-6) from the longitudinal Melbourne Healthy Aging Study (MHAS). Subjects were classified as being cognitively 'stable' or 'declining' by an independent behavioural neurologist based on clinical assessment and serial word-list recall scores from the preceding 6-10 years. Decline was calculated from the slope of the word-list recall scores. Abeta burden was quantified using Standardized Uptake Value normalized to cerebellar cortex. Ten subjects were clinically classified as declining. At the time of the PET scans, three of the declining subjects had mild cognitive impairment, one had AD, and six were declining but remained within the normal range for age on cognitive tests. Declining subjects were much more likely to show cortical PiB binding than stable subjects (70% vs. 17%, respectively). Neocortical Abeta burden correlated with word-list recall slopes (r=-0.78) and memory function (r=-0.85) in the declining group. No correlations were observed in the stable group. Abeta burden correlated with incident memory impairment and the rate of memory decline in the non-demented ageing population. These observations suggest that neither memory decline nor Abeta deposition are part of normal ageing and likely represent preclinical AD. Further longitudinal observations are required to confirm this hypothesis.

Current trends in the management of acute appendicitis

BACKGROUND

While laparoscopic appendectomy (LA) has become established in the diagnosis and treatment of acute appendicitis, its utilisation compared to open appendectomy (OA) is variable.

AIM

To compare the utilisation and outcome of laparoscopic (LA) versus OA in an Irish regional hospital setting.

METHOD

Retrospective review of OA and LA performed from 2003 to 2005.

RESULTS

Intention-to-treat analysis of 787 patients in this study revealed that 149 patients (19%) had LA and 638 patients (81%) had OA. Consultants were significantly more likely than trainees to undertake a LA (P < 0.0001). Twenty-two complications (2.8%) were recorded in the post-operative period. The overall negative appendectomy rate by histopathology was 17% with no significant difference between the rate in the LA group (19%) and the OA (17%) group.

CONCLUSION

Mean length of stay and complication rate were comparable between the LA and OA groups.

High affinity Fc receptor binding and potent induction of antibody-dependent cellular cytotoxicity (ADCC) in vitro by anti-epidermal growth factor receptor antibody cetuximab

3041

Background: Cetuximab is an IgG1 monoclonal antibody specific for human epidermal growth factor receptor (EGFR). Cetuximab acts as a functional antagonist by blocking ligand (EGF and TGFa) binding to EGFR and, therefore, inhibits EGFR activation and downstream signaling in tumor cells. Methods: In the present study, we analyzed the binding activity of cetuximab to human Fc receptors and tested whether cetuximab can elicit antibody-dependent cellular cytotoxicity (ADCC) in vitro using tumor cell lines expressing various levels of EGFR. Results: Cetuximab bound to human FcRI and FcRIII with high affinity (EC50 of 0.13 nM and 6 nM, respectively), whereas an aglycosylated form of cetuximab or an IgG2 antibody to EGFR (panitumumab) did not bind to FcRI and FcRIII. A panel of head and neck, colon, and breast tumor cell lines were tested for cetuximab-mediated ADCC using human peripheral blood mononuclear cells (PBMC) from normal donors as effector cells. We found that cetuximab-induced ADCC to these tumor cell lines ranging from 20–90% specific killing. Interestingly, the extent of ADCC induced by cetuximab correlated with the level of EGFR expression on cell surface. The aglycosylated form of cetuximab or panitumumab, did not elicit ADCC of EGFR expressing tumor cells, even though cetuximab and panitumumab bind to EGFR with similar affinity (Kd=87 pM and 83 pM, respectively). To identify the immune cell population responsible for ADCC, NK cells were isolated from PBMC and tested in an ADCC assay. Purified NK cells elicited high levels of specific killing of cetuximab bound tumor cells, suggesting that NK cells are one of effector cell populations in human PBMCs responsible for the observed ADCC activity. Conclusions: Thus, cetuximab can effectively link effector cells to EGFR expressing tumor cells and mediate potent ADCC against EGFR-expressing human tumors.

[Table: see text]

A stromal-associated gene expression signature predicting for survival in a series of patients with advanced high-grade serous ovarian cancer

5552

Background: Prognostic gene expression signatures have been derived for undissected serous ovarian epithelial tumors, yet the specific contribution of stromal cells to patient survival has not been addressed. The aim of this study is to identify stromal genes impacting patient survival in the context of serous ovarian cancer. Methods: Expression profiling utilizing Affymetrix U133 Plus 2.0 oligonucleotide arrays was completed for 50 microdissected stromal samples derived from high-grade, late-stage serous tumors displaying a broad spectrum of survival endpoints. A semi-supervised dimension reduction method employing multivariate Cox regression and principal components analysis was applied to the expression data to identify genes associated with patient survival and establish a predictive model. qRT-PCR was employed to validate the microarray expression data. Results: Cox regression analysis identified 267 significant genes. The first 6 principal components of these genes, representing >65% of total variance, entered a multivariate Cox model through which the relative hazard of future patients can be predicted. To confirm our finding, the microarray data underwent leave-one-out validation. The patients were equally divided into low- and high-risk groups and non-parametric Kaplan-Meier analysis and log rank test demonstrated the two groups were significantly different in survival (p = 0.0115). Genes associated with cell survival and migration were identified in the prognostic signature. For validation, qRT-PCR data for all 50 specimens was correlated with microarray expression values for a series of select prognostic genes. Conculsions: In this study, we characterized and validated a stromal dervied prognostic signature associated with poor patient survival. Contained in this novel predictor may be stromal targets suitable for the design of new therapeutic interventions, or use as independent diagnostic markers.

No significant financial relationships to disclose.

Imaging beta-amyloid burden in aging and dementia

OBJECTIVE

To compare brain beta-amyloid (Abeta) burden measured with [(11)C]Pittsburgh Compound B (PIB) PET in normal aging, Alzheimer disease (AD), and other dementias.

METHODS

Thirty-three subjects with dementia (17 AD, 10 dementia with Lewy bodies [DLB], 6 frontotemporal dementia [FTD]), 9 subjects with mild cognitive impairment (MCI), and 27 age-matched healthy control subjects (HCs) were studied. Abeta burden was quantified using PIB distribution volume ratio.

RESULTS

Cortical PIB binding was markedly elevated in every AD subject regardless of disease severity, generally lower and more variable in DLB, and absent in FTD, whereas subjects with MCI presented either an "AD-like" (60%) or normal pattern. Binding was greatest in the precuneus/posterior cingulate, frontal cortex, and caudate nuclei, followed by lateral temporal and parietal cortex. Six HCs (22%) showed cortical uptake despite normal neuropsychological scores. PIB binding did not correlate with dementia severity in AD or DLB but was higher in subjects with an APOE-epsilon4 allele. In DLB, binding correlated inversely with the interval from onset of cognitive impairment to diagnosis.

CONCLUSIONS

Pittsburgh Compound B PET findings match histopathologic reports of beta-amyloid (Abeta) distribution in aging and dementia. Noninvasive longitudinal studies to better understand the role of amyloid deposition in the course of neurodegeneration and to determine if Abeta deposition in nondemented subjects is preclinical AD are now feasible. Our findings also suggest that Abeta may influence the development of dementia with Lewy bodies, and therefore strategies to reduce Abeta may benefit this condition.

Adsorption of copper ion on magnetite-immobilised chitin

The adsorption of Cu2+ from aqueous solution by magnetite-immobilised chitin (MC) was studied in batch mode. Two conventional adsorbents, cation exchange resin (CER) and activated carbon (AC) were used for the comparison. The physicochemical parameters including pH, concentration of adsorbent, temperature and initial Cu2+ concentration were optimised. Under the optimised conditions, the removal efficiencies of Cu2+ for MC, CER and AC were 91.67, 93.36 and 89.16%, respectively. In addition, the removal capacities of Cu2+ for MC, CER and AC were 56.71, 74.84 and 6.55 mg/g, respectively. The adsorption isotherm studies indicated that the adsorptive behaviour of Cu2+ on three adsorbents could be well described by the Langmuir model. The maximum adsorption capacities (qmax) for MC, CER and AC were 53.19, 89.29 and 5.82 mg/g, respectively. The applicability of the kinetic model has been investigated for MC. Experimental results indicated that a pseudo-second-order reaction model provided the best description of the data with a correlation coefficient 0.999 for different initial Cu2+ concentrations. The rate constants were also determined. Various thermodynamic parameters such as standard free energy (DeltaG 0), enthalpy (DeltaH 0) and entropy (DeltaS 0) were calculated for predicting the adsorption nature of MC. The results indicated that this system was a spontaneous and endothermic process.

Seroepidemiology of pertussis in the adult population of Singapore

INTRODUCTION

Pertussis is a highly communicable, vaccine-preventable respiratory disease and a frequent but often underestimated cause of prolonged cough illness in adults. Protection after childhood vaccination is minimal after 10 years without boosting. The need for adult booster depends on the national epidemiology.

MATERIALS AND METHODS

We did a seroepidemiological survey amongst the adult population (aged 18 to 45 years) of Singapore. None had received pertussis booster vaccine in the preceding 10 years. We measured IgG antibodies to pertussis whole cell antigen.

RESULTS

Two hundred and seventy subjects with the median age of 30 years were enrolled. We found positive IgG antibody levels in 97% of the population. Seropositivity was not associated with age, gender or race.

CONCLUSION

The seroprevalence in adults was much higher than the previously documented seroprevalence of around 50% in the adolescent age group in Singapore. The increase is most likely due to natural infection with B. pertussis. Pertussis booster vaccine for adolescents/young adults in Singapore would be indicated.

La lunga attesa: towards a molecular approach to neuroimaging and therapeutics in Alzheimer's disease

Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterised by the gradual onset of dementia. The pathological hallmarks of the disease are Aβ amyloid plaques, neurofibrillary tangles (NFT), synaptic loss and reactive gliosis. Current diagnosis of AD is made by clinical, neuropsychologic, and neuroimaging assessments. Routine structural neuroimaging evaluation with computed tomography (CT) and magnetic resonance imaging (MRI) is based on non-specific features such as atrophy, a late feature in the progression of the disease, hence the crucial importance of developing new approaches for early and specific recognition at the prodromal stages of AD. Functional neuroimaging techniques such as functional magnetic resonance imaging (fMRI), magnetic resonance spectroscopy (MRS), positron emission tomography (PET) and single photon emission computed tomography (SPECT), possibly in conjuction with other related Aβ biomarkers in plasma and CSF, could prove to be valuable in the differential diagnosis of AD, as well as in assessing prognosis. With the advent of new therapeutic strategies aimed at reducing the Aβ amyloid burden in the brain, there is increasing interest in the development of MRI contrast agents and PET and SPECT radioligands that will permit the assessment of Aβ amyloid burden in vivo. - ma dov'è / la lenta processione di stagioni / che fu un'alba infinita e senza strade, / dov'è la lunga attesa e qual è il nome / del vuoto che ci invade. - Eugenio Montale.

Cooperative antitumor activity between the retinoid X receptor (RXR)-selective agonist bexarotene and EGFR-tyrosine kinase inhibitors in preclinical models of NSCLC

17073

Background: Gefitinib and erlotinib, small molecule inhibitors of the EGFR-tyrosine kinase (EGFR-TKI), can have antitumor activity in patients with advanced NSCLC. However, analysis of clinical samples and in vitro characterization of NSCLC cell lines has revealed EGFR mutations that correlate with the clinical responses. While EGFR-mutant cell lines are hypersensitive to EGFR-TKI-mediated growth inhibition and have a greater tendency to undergo apoptosis in response to EGFR inhibition, wild-type EGFR cell lines undergo growth inhibition only at high concentrations, and are resistant to apoptosis induction. Bexarotene (Targretin) is a RXR modulator with clinical activity enhancing survival in a subset of NSCLC patients. We have shown that bexarotene can suppress the growth of epithelial tumors by modulating the expression and function of the EGFR pathway. This study examined the effect of bexarotene/EGFR-TKI combinations in preclinical models of NSCLC, and evaluated the possible molecular mechanisms for cooperative antitumor activity between these agents. Results: Bexarotene enhanced the activity of gefitinib in most of the cell lines tested, and did so regardless of their EGFR mutation status or intrinsic sensitivity to gefitinib alone. Resistant lines were sensitized by the combination, which decreased gefitinib IC50s to clinically achievable concentrations. Bexarotene increased the pro-apoptotic activity of both gefitinib and erlotinib, an effect which was paralleled by enhanced repression of p-Akt and p-Her2 levels by the combinations. In ex vivo cultures of human NSCLC explant tissue, the addition of bexarotene enhanced the growth inhibitory activity of both gefitinib and erlotinib. Finally, combinations of bexarotene and EGFR-TKI produced growth inhibition of TKI-resistant A427 NSCLC xenograft tumors that was superior to either agent alone. Conclusions: These results indicate that bexarotene can sensitize NSCLC cells which are unresponsive to the effects of EGFR-TKIs, resulting in cooperative growth inhibition and apoptosis induction. Combination therapy using bexarotene in conjunction with EGFR-TKIs may provide a powerful new therapeutic strategy.

[Table: see text]

Bexarotene prevents and reverses gemcitabine resistance in non-small-cell lung cancer cells by affecting gene amplification

2057

Background: Bexarotene (BEX) is a retinoid X receptor selective drug approved for treatment of CTCL and has activity in various cancers. Here we evaluate its effect on acquired drug resistance towards gemcitabine (GEM) in Calu3 NSCLC models. Methods: Parental or GEM-resistant Calu3 NSCLC cells were treated with BEX and GEM as single agents or in combination. Over the treatment course the cells were evaluated for molecular changes (RNA expression and DNA amplification), which were associated with resistance status. Results: Calu3 cells treated with repeated cycles of GEM alone gradually developed resistance to this drug. However, inclusion of BEX prevented the development of resistance and cells remained chemosensitive. Microarray analysis showed a strong increase of rrm1 (ribonucleotide reductase M1) expression in the resistant cells (Calu3-GemR), a gene known to be involved in GEM resistance. In addition, the expression of genes surrounding the chromosomal location of rrm1 was increased suggesting that resistance was due to gene amplification at the 11p15 locus. This was confirmed by analysis of genomic DNA, indicating a 20-fold increase of rrm1 gene copy number. To evaluate BEX’s activity on pre-existing GEM-resistance, Calu3-GemR cells were treated with ten 10-day cycles of vehicle, GEM, BEX, or GEM plus BEX. After 4 treatment cycles the cultures treated with the combination regimen showed a loss in cell numbers, which continued until the end of the 10th cycle. This indicated a re-sensitization of the Calu3-GemR cells to treatment. The cultures treated with the single drug regimens expanded as the vehicle controls. However, analysis of RNA and DNA samples collected over the treatment course revealed that rrm1 gene amplification was gradually reduced even in the cultures treated with BEX alone, reaching parental levels at the end of the study. As expected from these data, the BEX-treated Calu3-GemR cells were again sensitive to GEM. Conclusions: The data indicate that bexarotene can re-sensitize GEM-resistant tumor cells by reversing gene amplification. This suggests that bexarotene may have general clinical utility in cancers where drug-resistance by gene amplification is a major obstacle to successful therapy.

[Table: see text]

Utility of the Health Belief Model in predicting compliance of screening in patients with chronic hepatitis B

BACKGROUND

Regular surveillance is recommended for patients with chronic hepatitis B, to select candidates for anti-viral therapy and detect early complications. However, factors that determine compliance are not well studied.

AIM

To determine the utility of the Health Belief Model in explaining non-compliance, among a group of chronic hepatitis B patients for screening.

METHODS

A total of 192 chronic hepatitis B patients who responded to advertisement for free screening took part in a telephonic interview study. Subjects were asked about the five constructs of the Health Belief Model, and factors associated with recent screening were analysed.

RESULTS

The mean age of the subjects was 42.1 +/- 0.7 years; 77% white male, and 97% Chinese. About 108 patients (56%) had recent screening. At multivariate analysis, only the ability to remember date of follow-up (OR: 4.37; 95% CI: 2.07-9.17) and the perception of having to wait a long time for venepuncture (OR: 0.38; 95% CI: 0.19-0.79) were significantly associated with recent screening.

CONCLUSION

Future public health measures should include improving the logistics of follow-up procedures and providing reminders for screening to improve compliance.

A phase I dose-escalation study of docetaxel with granulocyte colony-stimulating factor support in patients with solid tumours

BACKGROUND

Docetaxel is a widely active cytotoxic agent. The principal dose-limiting toxicities (DLTs) of the 3-weekly regimen are neutropenia and febrile neutropenia. Use of prophylactic granulocyte colony-stimulating factor (G-CSF) may allow higher doses of docetaxel to be administered with potentially greater anticancer efficacy. The objectives of this study were to determine the maximum tolerated dose (MTD) and toxicity profile of docetaxel given with G-CSF support.

PATIENTS AND METHODS

Eligible patients had solid tumours and were aged 18-75 years with a WHO performance status of up to 2. Strict criteria for liver function were followed. Patients may have received one previous regimen of chemotherapy in addition to adjuvant chemotherapy. Cohorts of three to six patients received docetaxel over 60-90 min every 3 weeks, commencing at 110 mg/m(2) and escalating at 10 mg/m(2) increments. Patients also received G-CSF 5 micro g/kg/day until neutrophil recovery. A 3-day corticosteroid prophylaxis was given.

RESULTS

Twenty-nine patients with median age 55 years (range 29-75) were included. Fourteen (48%) had previously received chemotherapy. At the 170 mg/m(2) dose level (the MTD), two of three patients had DLTs and 160 mg/m(2) was determined to be the recommended dose. The principal DLTs were skin and neurosensory toxicity. Asthenia was frequent, especially at dose levels >/=140 mg/m(2). Grade 4 neutropenia occurred in only 10 patients (35%) and was not dose related, with febrile neutropenia in three patients (10%).

CONCLUSIONS

Docetaxel may be escalated considerably above standard doses when administered with G-CSF support. The recommended dose for phase II studies is 160 mg/m(2). With escalated-dose docetaxel, DLTs were non-haematological and qualitatively similar to the toxicity profile at standard doses.

Multi-centre assessment of the Spiegelberg compliance monitor: interim results

Analyses of a multi-centre database of 71 patients at risk of raised ICP showed that in head injured patients (n = 19) and tumour patients (n = 13) clear inverse relationships of ICP vs compliance exist. SAH patients (n = 5) appear to exhibit a biphasic relationship between ICP and compliance, however greater numbers of patients need to be recruited to this group. Patients with hydrocephalus (n = 34) show an initial decrease in compliance while ICP is less than 20 mmHg, thereafter compliance does not show a dependence upon ICP. A power analysis confirmed that sufficient numbers of patients have been recruited in the hydrocephalus group and a ROC analysis determined that a mean compliance value of 0.809 (lower and upper 95% CL = 0.725 & 0.894 resp.) was a critical threshold for raised ICP greater than 10 mmHg. Preliminary time-series analyses of the ICP and compliance data is revealing evidence that the cumulative time compliance is in a low compliance state (< 0.5 ml/mmHg), as a proportion of total monitoring time, increases more rapidly than the cumulative time ICP is greater than 25 mmHg. Before trials testing compliance thresholds can be designed, we need to consider not just the absolute threshold, but the duration of time spent below threshold. A survey may be required to identify a consensus of what is the minimum duration of raised ICP above 25 mmHg needed to instigate treatment.

Sternal osteomyelitis caused by Aspergillus fumigatus in a patient with previously treated Hodgkin's disease

This report details the case of a 67 year old woman with sternal osteomyelitis caused by Aspergillus fumigatus. She was diagnosed with Hodgkin's disease in 1975 and was successfully treated with chemotherapy. A lobectomy for recurrence localised to the left lung was complicated nine years later by severe bronchiectasis, for which she required a total left sided pneumonectomy. At surgery, a non-invasive aspergillus was found. She presented eight years later with symptoms that were initially attributed to recurrence of Hodgkins's disease, but on investigation were found to be caused by fungal sternal osteomyelitis. Treatment with itraconazole suspension at a dose of 400 mg daily was successful.