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

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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

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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

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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.