Diagnostic accuracy of the BACs-on-Beads™ assay versus karyotyping for prenatal detection of chromosomal abnormalities: a retrospective consecutive case series

OBJECTIVE

To evaluate the diagnostic performance of the BACs-on-Beads(™) (BoBs(™)) assay for prenatal detection of chromosomal abnormalities.

DESIGN

Retrospective study.

SETTING

Tertiary prenatal diagnosis centre.

POPULATION

Women referred for prenatal diagnosis.

METHODS

We retrieved 2153 archived DNA samples collected between January 2010 and August 2011 for the BoBs(™) assay. These samples had previously been tested by quantitative fluorescence polymerase chain reaction (QF-PCR) and karyotyping. In the BoBs(™) assay a sample was defined as normal disomic when the ratio of the fluorescence intensities in a chromosome locus lay within the threshold (mean ratio ± 2SD), and as deleted or duplicated when the ratio was below the lower threshold (0.6-0.8) or above the upper threshold (1.3-1.4), respectively. The BoBs(™) results were further validated by microarray and compared in a blinded manner with the original QF-PCR and karyotyping results.

MAIN OUTCOME MEASURES

Concordance of any numerical, structural, and submicroscopic chromosomal abnormalities between the methods.

RESULTS

BACs-on-Beads(™) was similar to karyotyping and QF-PCR in detecting trisomy 13, trisomy 18, trisomy 21, and sex chromosomal aneuploidies, and superior to QF-PCR in detecting major structural abnormalities (53.3 versus 13.3%) and mosaicism (28.6 versus 0%) involving chromosomal abnormalities other than the common aneuploidies. BoBs(™) detected six microdeletion syndromes missed by karyotyping and QF-PCR; however, BoBs(™) missed two cases of triploidy identified by QF-PCR. Therefore, the sensitivity of BoBs(™) is 96.7% (95% CI 92.6-98.7%), and its specificity is 100% (95% CI 99.8-100%).

CONCLUSIONS

BACs-on-Beads(™) can replace QF-PCR for triaging in prenatal diagnosis, and gives a better diagnostic yield than current rapid aneuploidy tests.

Two BRM promoter insertion polymorphisms increase the risk of early-stage upper aerodigestive tract cancers

Brahma (BRM) has a key function in chromatin remodeling. Two germline BRM promoter insertion–deletion polymorphisms, BRM-741 and BRM-1321, have been previously associated with an increased risk of lung cancer in smokers and head and neck cancer. To further evaluate their role in cancer susceptibility particularly in early disease, we conducted a preplanned case–control study to investigate the association between the BRM promoter variants and stage I/II upper aerodigestive tract (UADT) cancers (i.e., lung, esophageal, head and neck), a group of early-stage malignancies in which molecular and genetic etiologic factors are poorly understood. The effects of various clinical factors on this association were also studied. We analyzed 562 cases of early-stage UADT cancers and 993 matched healthy controls. The double homozygous BRM promoter variants were associated with a significantly increased risk of early stage UADT cancers (adjusted odds ratio [aOR], 2.46; 95% confidence interval [CI], 1.7–3.8). This association was observed in lung (aOR, 2.61; 95% CI, 1.5–4.9) and head and neck (aOR, 2.75; 95% CI, 1.4–5.6) cancers, but not significantly in esophageal cancer (aOR, 1.66; 95% CI, 0.7–5.8). There was a nonsignificant trend for increased risk in the heterozygotes or single homozygotes. The relationship between the BRM polymorphisms and early-stage UADT cancers was independent of age, sex, smoking status, histology, and clinical stage. These findings suggest that the BRM promoter double insertion homozygotes may be associated with an increased risk of early-stage UADT cancers independent of smoking status and histology, which must be further validated in other populations.

Dissociation of doublecortin expression and neurogenesis in unipolar brush cells in the vestibulocerebellum and dorsal cochlear nucleus of the adult rat

We have previously shown expression of the protein doublecortin (DCX) in unipolar brush cells (UBCs) in the dorsal cochlear nucleus and vestibulocerebellum of the adult rat. We also saw DCX-immunoreactive elements with the appearance of neuroblasts around the fourth ventricle. Expression of DCX is seen in newborn and migrating neurons and hence considered a correlate of neurogenesis. There were two interpretations of the expression of DCX in UBCs. One possibility is that there might be adult neurogenesis of this cell population. Adult neurogenesis is now well-established, but only for the dentate gyrus of the hippocampus and the subventricular zone. The other possibility is that there is prolonged expression of DCX in adult UBCs that may signal a unique role in plasticity of these neurons. We tested the neurogenesis hypothesis by systemic injections of bromodeoxyuridine (BrdU), a thymidine analog, followed by immunohistochemistry to examine the numbers and locations of dividing cells. We used several different injection paradigms, varying the dose of BrdU, the number of injections and the survival time to assess the possibility of neuronal birth and migration. We saw BrdU-labeled cells in the cerebellum and brainstem; cell division in these regions was confirmed by immunohistochemistry for the protein Ki67. However, neither the numbers nor the distribution of labeled nuclei support the idea of adult neurogenesis and migration of UBCs. The function of DCX expression in UBC's in the adult remains to be understood.

BRM promoter insertion/deletion polymorphisms in hepatocellular carcinoma risk and survival

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Background: MEF2D and HDAC9 regulate the expression of BRM, the catalytic subunit of SWI/SNF (chromatin remodeling complex). MEF2D binding sites are created in the BRM promoter by two germline insertion/deletion polymorphisms (BRM-741, BRM-1321), which mediate epigenetic silencing. We recently identified BRM as a potential drug target and a susceptibility gene for lung and head and neck cancers, while others reported its association with HCC risk in Asians. BRM also correlates with prognosis in lung and esophageal cancers (ASCO 2013; abstracts 11057, 4077). In this analysis, we assessed the effects of the BRM promoter variants on risk and overall survival (OS) in HCC from a North American centre (Toronto). Methods: We conducted a case-control study with 266 histologically confirmed HCC cases and 536 age/sex distribution-matched healthy controls. Survival of the cases was obtained from medical records. Association between the BRM polymorphisms and HCC risk was analyzed by multivariate logistic regression adjusted for age, sex, race, smoking and BMI; their impact on OS was evaluated by Cox proportional hazard regression adjusted for age, sex, treatment intent and Hepatitis B status. Results: Median age was 62 years; 83% were male. Hepatitis B and C infections affected 34% and 31% of cases, respectively. 83% of patients were Child Pugh A at diagnosis, and 66% received initial curative therapy (surgical resection rate 32%). There were 13% deaths at a median follow-up of 24.1 months. There was no significant association between BRM polymorphisms and HCC risk: the adjusted risk odds ratios of the homozygous BRM variants, relative to wild-type, were 0.87 (95% CI: 0.53-1.45; BRM-741) and 1.01 (95% CI: 0.78-1.29; BRM-1321), and 0.94 (95% CI: 0.48-1.86) for the double homozygotes vs. double wild-type. The adjusted hazard ratios for OS were 5.77 (95% CI: 2.9-11.5; BRM-741) and 4.09 (95% CI: 2.2-7.5; BRM-1321) for each variant allele; the double homozygotes were also highly associated with OS compared to double wild-type (p<0.0001). Conclusions: Two functional BRM promoter polymorphisms did not increase the risk of HCC. However, they were strongly associated with OS despite short median follow-up. SPC and RH are co-senior authors.

Differences in clinical characteristics and treatment in hepatocellular carcinoma between Asians and non-Asians

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Background: Studies have demonstrated clinical differences in hepatocellular carcinoma (HCC) between Asians (AS) and non-Asians (NAS). In the US, AS are less likely to undergo liver transplant compared to Caucasians. Despite the large immigrant population in Canada, there has been no prior comparison of HCC in AS and NAS in the context of the Canadian universal health care system. We retrospectively evaluated the ethnic differences in HCC at the largest cancer centre in Canada. Methods: We analyzed 268 patients who enrolled in a Genetic Epidemiology Study of HCC (April 2010 to February 2013), where patients were asked to complete a questionnaire and give a blood sample at their first visit. Relevant clinical data were extracted and analyzed by descriptive statistics, t-test or Chi-square test. Results: The study population had a mean age of 61 years and 83% males. There were 45% AS, 49% Caucasians, and 6% other ethnicities. Etiologies of HCC included: Hepatitis B (HBV) 34%, Hepatitis C (HCV) 32%, non-alcoholic steatohepatitis 15%, alcohol 18%. Compared to NAS, HCC patients of Asian ancestry had significantly higher rates of HBV (60% vs. 12%, p<0.001). At diagnosis, 83% of patients were Child-Pugh A (mean MELD score 9.2). Ethnicity had no impact on Child-Pugh class, multifocal disease or macrovascular invasion. However, MELD scores were lower in AS (p=0.02). Overall, 71% of cases were initially treated with curative intent. Patients underwent various treatment modalities: liver transplant 13%, resection 31%, radiofrequency ablation 39%, transarterial chemoembolization (TACE) 21%, radiation 17%, systemic therapy 27%. AS had higher resection rates (41% vs. 22%, p<0.001), while no differences were observed for other treatments. Duration of response was 11.7 months for TACE (AS 14.2, NAS 10.5), 7.5 months for sorafenib (AS 6.8, NAS 8.1). Rate of intolerance to sorafenib was 24% (AS 27%, NAS 22%, p=0.63). This analysis was limited by inherent bias in the selection of study patients. Conclusions: AS with HCC tend to have HBV and lower MELD scores, and to undergo resection in a public health care setting with no differences in the uptake of other therapies. An analysis of survival based on ethnicity will be reported.

The impact of body mass index on survival in stage 3 and 4 lung cancer

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Background: Obesity is an adverse prognostic factor in several cancers, including colorectal, breast, endometrial and prostate. Studies on body mass index (BMI) and lung cancer outcomes are lacking. Understanding the clinical impact of body weight is important given the high prevalence of obesity globally. We retrospectively evaluated the BMI at diagnosis and its effects on survival in stage 3/4 lung cancer patients. Methods: 1,121 patients with stage 3/4 lung cancer were analyzed. Clinicopathologic data were collected retrospectively. Adjusted hazard ratios (aHR) for overall survival (OS) were generated by Cox regression for each BMI (kg/m2) category (underweight: <18.5, normal: 18.5-24.9, overweight: 25.0-29.9, obese: ≥30), after adjusting for age, gender, Charlson Comorbidity Index, performance status (PS), clinical stage and treatment regimen. Results: In this cohort (n=1,121), the frequencies of stage 3A, 3B and 4 lung cancers were 35%, 32% and 33%, respectively. There were 633 (57%) adenocarcinomas, 238 (21%) squamous cell carcinomas, 38 (3%) small cell lung cancers, and 210 (19%) other histologies. Patients had variable BMI: 82 (7%) underweight, 550 (49%) normal weight, 333 (30%) overweight, 156 (14%) obese. Being overweight/obese was associated with older age (p=0.002) and stage 3A disease (p=0.001); underweight patients were more likely current smokers (p<0.001). OS was significantly decreased with age ≥65, males, PS 2-3, stage 4, and lack of systemic therapy (p<0.001). Median OS in underweight, normal weight, overweight and obese patients were 14, 23, 24 and 26 months, respectively. Compared with BMI≥18.5, being underweight was associated with poorer OS (aHR 1.33, 95% CI 1.01-1.77, p=0.045), but not progression-free survival (aHR 1.12, 95% CI 0.86-1.46, p=0.414). The magnitude of this association was greatest in those aged <65 (aHR 1.57, 95% CI 1.11-2.22, p=0.011). Conclusions: Underweight patients with stage 3/4 lung cancer, especially if aged <65, have significantly poorer OS. Lower BMI was mostly observed in current smokers, while above normal BMI was seen in stage 3A. Unlike other cancers, obesity does not increase mortality in this population. The inverse BMI-survival relationship in lung cancer requires further study.

The effect of two BRM promoter variants on the risk of stage I/II upper aerodigestive tract cancers

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Background: BRM is a key subunit of the chromatin remodeling complex SWI/SNF and a putative tumor suppressor gene that is silenced in 15-20% of many solid tumors (PMID 15722796). Evidence suggests that it is epigenetically regulated, as two BRM promoter insertion variants (BRM-741 and BRM-1321) may lead to gene silencing by recruiting histone deacetylases. The presence of both homozygous BRM-741 and BRM-1321 highly correlate with loss of BRM expression and function in lung tumors, while increasing smoking-related lung cancer by two-fold (PMID 21478907). Also, the pharmacologic reversal of epigenetic changes of BRM offers a potential novel therapeutic approach (PMID 21478905). We assessed whether these BRM variants are associated with the risk of upper aerodigestive tract cancers, focusing on Stage I/II tumors that would most benefit from new screening and prevention strategies. Methods: BRM was genotyped by qPCR using TaqMan probes. 1,008 controls were matched to 595 cases by frequency distribution based on age, gender and smoking status. Multivariate logistic regression generated adjusted odds ratios (aOR). Results: The 595 cases were: 115 esophageal, 278 lung, and 202 head and neck cancers. 51% were adenocarcinomas; 60% were Stage I. The frequency of homozygozity was: BRM-741, 26%; BRM-1321, 23%; both variants, 15%. In the combined analysis, there was significant correlation between malignancy and homozygous BRM-741 (aOR 1.91 (95%CI 1.3-2.4); p=0.001) or BRM-1321 (aOR 1.94 (95%CI 1.4-2.7; p=3x10E-4). Being homozygous for both BRM variants carried an even greater risk (aOR 2.45 (95%CI 1.6-3.9); p=1x10E-5). This correlation was similar for adenocarcinomas (aOR 2.53 (95%CI 1.4-4.2); p=6x10E-4) and squamous cell carcinomas (aOR 2.33 (95%CI 1.3-4.4); p=8x10E-4). The increased cancer risk was also similar between these subgroups: head and neck, esophageal and lung cancers; Stage I and II patients; smokers and non-smokers. Conclusions: The two homozygous BRM variants increase the risk of early stage upper aerodigestive tumors by more than two-fold independent of smoking status. BRM promoter variants and their potential epigenetic effect may be early events in the evolution of these cancers.

Cell survival, DNA damage, and oncogenic transformation after a transient and reversible apoptotic response

Apoptosis serves as a protective mechanism by eliminating damaged cells through programmed cell death. After apoptotic cells pass critical checkpoints, including mitochondrial fragmentation, executioner caspase activation, and DNA damage, it is assumed that cell death inevitably follows. However, this assumption has not been tested directly. Here we report an unexpected reversal of late-stage apoptosis in primary liver and heart cells, macrophages, NIH 3T3 fibroblasts, cervical cancer HeLa cells, and brain cells. After exposure to an inducer of apoptosis, cells exhibited multiple morphological and biochemical hallmarks of late-stage apoptosis, including mitochondrial fragmentation, caspase-3 activation, and DNA damage. Surprisingly, the vast majority of dying cells arrested the apoptotic process and recovered when the inducer was washed away. Of importance, some cells acquired permanent genetic changes and underwent oncogenic transformation at a higher frequency than controls. Global gene expression analysis identified a molecular signature of the reversal process. We propose that reversal of apoptosis is an unanticipated mechanism to rescue cells from crisis and propose to name this mechanism "anastasis" (Greek for "rising to life"). Whereas carcinogenesis represents a harmful side effect, potential benefits of anastasis could include preservation of cells that are difficult to replace and stress-induced genetic diversity.

Incidence and risk factors for early hepatotoxicity and its impact on survival in patients with myelofibrosis undergoing allogeneic hematopoietic cell transplantation

Allogeneic hematopoietic cell transplantation (HCT) is commonly associated with hepatic complications. Patients with myelofibrosis (MF) often develop liver dysfunction in the early posttransplantation period; however, this has not yet been studied in a systematic fashion. We retrospectively evaluated 53 patients with MF who underwent HCT to assess the prevalence of acute liver toxicity and risk factors and the impact on survival. We compared the prevalence of acute hepatic complications in that group and a matched control group of 53 patients with myelodysplastic syndrome (MDS). In the MF group, during the first 6 weeks after HCT, the incidence of mild (34.2-102.6 μM), moderate (102.6-342 μM), and severe (>342 μM) hyperbilirubinemia was 34%, 40%, and 4%, respectively (normal, <22 μM). The incidence of mild/moderate transaminitis (2-10 times the upper limit of normal) was 23%, and that of severe transaminitis (>10 times the upper limit of normal) was 6%. Veno-occlusive disease as defined by the Baltimore criteria was observed in 19 patients (36%) in the MF group. Compared with MDS, MF was associated with a significantly higher incidence of moderate/severe hyperbilirubinemia (44% versus 21%; P = .02) and veno-occlusive disease (36% versus 19%; P = .05). A history of portal hypertension, biopsy-proven hepatic iron overload, or splanchnic vein thrombosis was a strong predictor of moderate/severe hyperbilirubinemia (P = .02). Acute hepatocellular injury with moderate/severe hyperbilirubinemia or transaminitis was associated with inferior survival at 12 months (P = .02) in the MF group. We conclude that patients with MF are at significant risk of early hepatotoxicity after HCT, which is associated with an adverse impact on survival.

Unraveling the genetics of cancer: genome sequencing and beyond

Advances in next-generation sequencing technology are enabling the systematic analyses of whole cancer genomes, providing insights into the landscape of somatic mutations and the great genetic heterogeneity that defines the unique signature of an individual tumor. Moreover, integrated studies of the genome, epigenome, and transcriptome reveal mechanisms of tumorigenesis at multiple levels. Progress in sequencing technologies and bioinformatics will improve the costs, sensitivity, and accuracy of detecting somatic mutations, while large-scale projects are underway to coordinate cancer genome sequencing at the global level to facilitate the generation and dissemination of high-quality uniform genetic data. These developments will create opportunities for deeper studies of cancer genetics and the clinical application of genome sequencing, and will motivate further research in cancer pathogenesis.

Clinics in diagnostic imaging (136). Chronic Schistosoma japonica infection of the liver

A 37-year-old man from China was initially seen at the urology clinic for symptoms of urinary colic. Plain computed tomography (CT) imaging of the kidneys, ureters and bladder was performed, which (in addition to demonstrating renal calculi) revealed incidental findings of 'turtleback' septal and capsular calcifications, features pathognomonic for schistosomiasis japonica. Other classical features were demonstrated on the triphasic hepatic CT imaging that was subsequently performed. The clinical course, radiological features and complications of schistosomiasis japonica are discussed.

The novel immunoregulatory molecule FGL2: a potential biomarker for severity of chronic hepatitis C virus infection

BACKGROUND & AIMS

This report describes the use of a novel sensitive and specific ELISA for the measurement of human fibrinogen-like protein 2 (FGL2/fibroleukin), a novel effector of natural regulatory T (Treg) cells, to predict the course of chronic hepatitis C viral infection (HCV).

METHODS

Plasma levels of FGL2 were measured in HCV patients and compared to healthy controls and to patients with alcoholic liver disease.

RESULTS

FGL2 levels were significantly higher in HCV patients (84.3+/-89.1 ng/ml, n=80) compared to healthy controls (36.4+/-21.9 ng/ml, n=30, p<0.001), to a subset of patients who cleared HCV following anti-viral treatment (16.6+/-19.7 ng/ml, n=32, p<0.001), and to patients with inactive alcoholic liver disease (18.8+/-17.4 ng/ml, n=24, p<0.001). Among HCV patients, plasma levels of FGL2 correlated significantly with the stage of fibrosis (p=0.001) and were significantly higher in patients with cirrhosis (164.1+121.8 ng/ml, n=60) compared to non-cirrhotics (57.7+/-52.8 ng/ml, n=20, p=0.001). Genotype 1 patients had significantly higher levels of FGL2 (98.1+/-100.3 ng/ml, n=60) compared to patients with genotype 2/3 (41.5+/-38.6 ng/ml, n=20, p=0.0008). Patients with genotype 2/3 had FGL2 levels similar to healthy controls (41.5+/-38.6 vs. 36.41+/-21.9 ng/ml, p=ns). Infiltrating lymphocytes in liver biopsies of HCV patients were positive for either FGL2 or FoxP3 (a marker of Treg cells) or expressed both markers.

CONCLUSIONS

This report documents the development of a sensitive ELISA for measurement of plasma levels of FGL2 an effector Treg cells, which correlates with the severity of HCV infection.

Kisspeptin/Gpr54-independent gonadotrophin-releasing hormone activity in Kiss1 and Gpr54 mutant mice

The kisspeptin/Gpr54 signalling pathway plays a critical role in reproduction by stimulating the secretion of gonadotrophin-releasing hormone (GnRH), yet mice carrying mutations in Kiss1 (which encodes kisspeptin) or Gpr54 exhibit partial sexual maturation. For example, a proportion of female Kiss1(-/-) and Gpr54(-/-) mice exhibit vaginal oestrus, and some male Kiss1(-/-) and Gpr54(-/-) mice exhibit spermatogenesis. To characterise this partial sexual maturation, we examined the vaginal cytology of female Kiss1(-/-) and Gpr54(-/-) mice over time. Almost all mutant mice eventually enter oestrus, and then spontaneously transition from oestrus to dioestrus and back to oestrus again. These transitions are not associated with ovulation, and the frequency of these transitions increases with age. The oestrus exhibited by female Kiss1(-/-) and Gpr54(-/-) mice was disrupted by the administration of the competitive GnRH antagonist acyline, which also resulted in lower uterine weights and, in Kiss1(-/-) mice, lower serum follicle-stimulating hormone (FSH) and luteinising hormone (LH) concentrations. Similarly, male Kiss1(-/-) and Gpr54(-/-) mice treated with acyline had smaller testicular sizes and an absence of mature sperm. In addition to examining intact Kiss1(-/-) and Gpr54(-/-) mice, we also assessed the effects of acyline on gonadotrophin concentrations in gonadectomised mice. Gonadectomy resulted in a significant increase in serum FSH concentrations in male Gpr54(-/-) and Kiss1(-/-) mice. Acyline administration to gonadectomised Kiss1(-/-) and Gpr54(-/-) male mice lowered serum FSH and LH concentrations significantly. By contrast to males, gonadectomy did not result in significant gonadotrophin changes in female Kiss1(-/-) and Gpr54(-/-) mice, but acyline administration was followed by a decrease in LH concentrations. These results demonstrate that, although kisspeptin signalling is critical for the high levels of GnRH activity required for normal sexual maturation and for ovulation, Kiss1(-/-) and Gpr54(-/-) mice retain some degree of GnRH activity. This GnRH activity is sufficient to produce significant effects on vaginal cytology and uterine weights in female mice and on spermatogenesis and testicular weights in male mice.

The novel CD4+CD25+ regulatory T cell effector molecule fibrinogen-like protein 2 contributes to the outcome of murine fulminant viral hepatitis

Fulminant viral hepatitis (FH) remains an important clinical problem in which the underlying pathogenesis is not well understood. Here, we present insight into the immunological mechanisms involved in FH caused by murine hepatitis virus strain 3 (MHV-3), indicating a critical role for CD4(+)CD25(+) regulatory T cells (Tregs) and production of the novel Treg effector molecule FGL2. Before infection with MHV-3, susceptible BALB/cJ mice had increased numbers of Tregs and expression of fgl2 messenger RNA (mRNA) and FGL2 protein compared with resistant A/J mice. After MHV-3 infection, plasma levels of FGL2 in BALB/cJ mice were significantly increased, correlating with increased percentage of Tregs. Treatment with anti-FGL2 antibody completely inhibited Treg activity and protected susceptible BALB/cJ mice against MHV-3-liver injury and mortality. Adoptive transfer of wild-type Tregs into resistant fgl2(-/-) mice increased their mortality caused by MHV-3 infection, whereas transfer of peritoneal exudate macrophages had no adverse effect.

CONCLUSION

This study demonstrates that FGL2 is an important effector cytokine of Tregs that contributes to susceptibility to MHV-3-induced FH. The results further suggest that targeting FGL2 may lead to the development of novel treatment approaches for acute viral hepatitis infection.

Targeted deletion of fgl2 leads to impaired regulatory T cell activity and development of autoimmune glomerulonephritis

Mice with targeted deletion of fibrinogen-like protein 2 (fgl2) spontaneously developed autoimmune glomerulonephritis with increasing age, as did wild-type recipients reconstituted with fgl2-/- bone marrow. These data implicate FGL2 as an important immunoregulatory molecule and led us to identify the underlying mechanisms. Deficiency of FGL2, produced by CD4+CD25+ regulatory T cells (Treg), resulted in increased T cell proliferation to lectins and alloantigens, Th 1 polarization, and increased numbers of Ab-producing B cells following immunization with T-independent Ags. Dendritic cells were more abundant in fgl2-/- mice and had increased expression of CD80 and MHCII following LPS stimulation. Treg cells were also more abundant in fgl2-/- mice, but their suppressive activity was significantly impaired. Ab to FGL2 completely inhibited Treg cell activity in vitro. FGL2 inhibited dendritic cell maturation and induced apoptosis of B cells through binding to the low-affinity FcgammaRIIB receptor. Collectively, these data suggest that FGL2 contributes to Treg cell activity and inhibits the development of autoimmune disease.

Targeted deletion of fgl2 leads to impaired regulatory T cell activity and development of autoimmune glomerulonephritis

Mice with targeted deletion of fibrinogen-like protein 2 (fgl2) spontaneously developed autoimmune glomerulonephritis with increasing age, as did wild-type recipients reconstituted with fgl2-/- bone marrow. These data implicate FGL2 as an important immunoregulatory molecule and led us to identify the underlying mechanisms. Deficiency of FGL2, produced by CD4+CD25+ regulatory T cells (Treg), resulted in increased T cell proliferation to lectins and alloantigens, Th 1 polarization, and increased numbers of Ab-producing B cells following immunization with T-independent Ags. Dendritic cells were more abundant in fgl2-/- mice and had increased expression of CD80 and MHCII following LPS stimulation. Treg cells were also more abundant in fgl2-/- mice, but their suppressive activity was significantly impaired. Ab to FGL2 completely inhibited Treg cell activity in vitro. FGL2 inhibited dendritic cell maturation and induced apoptosis of B cells through binding to the low-affinity FcgammaRIIB receptor. Collectively, these data suggest that FGL2 contributes to Treg cell activity and inhibits the development of autoimmune disease.

Dynamic overload control for distributed call processors using the neural network method

Overload control of call processors in telecom networks is used to protect the network of call processing computers from excessive load during traffic peaks, and involves techniques of predictive control with limited local information. Here we propose a neural-network algorithm, in which a group of neural controllers are trained using examples generated by a globally optimal control method. Simulations show that the neural controllers have better performance than local control algorithms in both the throughput and the response to traffic upsurges. Compared with the centralized control algorithm, the neural control significantly decreases the computational time for making decisions and can be implemented in real time.

Impaired heart contractility in Apelin gene-deficient mice associated with aging and pressure overload

Apelin constitutes a novel endogenous peptide system suggested to be involved in a broad range of physiological functions, including cardiovascular function, heart development, control of fluid homeostasis, and obesity. Apelin is also a catalytic substrate for angiotensin-converting enzyme 2, the key severe acute respiratory syndrome receptor. The in vivo physiological role of Apelin is still elusive. Here we report the generation of Apelin gene-targeted mice. Apelin mutant mice are viable and fertile, appear healthy, and exhibit normal body weight, water and food intake, heart rates, and heart morphology. Intriguingly, aged Apelin knockout mice developed progressive impairment of cardiac contractility associated with systolic dysfunction in the absence of histological abnormalities. We also report that pressure overload induces upregulation of Apelin expression in the heart. Importantly, in pressure overload-induced heart failure, loss of Apelin did not significantly affect the hypertrophy response, but Apelin mutant mice developed progressive heart failure. Global gene expression arrays and hierarchical clustering of differentially expressed genes in hearts of banded Apelin(-/y) and Apelin(+/y) mice showed concerted upregulation of genes involved in extracellular matrix remodeling and muscle contraction. These genetic data show that the endogenous peptide Apelin is crucial to maintain cardiac contractility in pressure overload and aging.

Declines in tobacco brand recognition and ever-smoking rates among young children following restrictions on tobacco advertisements in Hong Kong

BACKGROUND

We compared the recognition of tobacco brands and ever-smoking rates in young children before (1991) and after (2001) the implementation of cigarette advertising restrictions in Hong Kong and identified continuing sources of tobacco promotion exposure.

METHODS

A cross-sectional survey of 824 primary school children aged from 8 to 11 (Primary classes 3-4) living in two Hong Kong districts was carried out using self-completed questionnaires examining smoking behaviour and recognition of names and logos from 18 tobacco, food, drink and other brands common in Hong Kong.

RESULTS

Ever-smoking prevalence in 2001 was 3.8 per cent (1991, 7.8 per cent). Tobacco brand recognition rates ranged from 5.3 per cent (Viceroy name) to 72.8 per cent (Viceroy logo). Compared with 1991, in 2001 never-smoker children recognized fewer tobacco brand names and logos: Marlboro logo recognition rate fell by 55.3 per cent. Similar declines were also seen in ever-smoker children, with recognition of the Marlboro logo decreasing 48 per cent. Recognition rates declined amongst both boys and girls. Children from non-smoking families constituted 51 per cent (426) of the sample, whereas 34.5 per cent (284), 8.5 per cent (70), 1.7 per cent (14) and 4.4 per cent (36) of the children had one, two, three or more than three smoking family members at home, respectively. Tobacco brand recognition rates and ever-smoking prevalence were significantly higher among children with smoking family members compared with those without. Among 12 possible sources of exposure to cigarette brand names and logos, retail stalls (75.5 per cent; 622), indirect advertisements (71.5 per cent; 589) and magazines (65.3 per cent; 538) were ranked the most common.

CONCLUSION

Advertising restrictions in Hong Kong have effectively decreased primary-age children's recognition of tobacco branding. However, these children remain vulnerable to branding, mostly through exposure from family smokers, point-of-sale tobacco advertisement and occasional promotions. Action to curb these is now required.

Corticosteroid therapy in a Chinese patient with nephropathy associated with human immunodeficiency virus infection

A 52-year-old man with 6 years' history of human immunodeficiency virus infection who was receiving highly active antiretroviral therapy presented with acute renal failure and nephrotic syndrome. Renal biopsy revealed features consistent with nephropathy associated with human immunodeficiency virus infection. Treatment consisted of intravenous methylprednisolone followed by oral prednisolone. The patient's renal function improved, although proteinuria persisted. Human immunodeficiency virus-associated nephropathy is very rare in Asian populations and is more common among blacks. To the best of our knowledge, this is the first documented case of nephropathy associated with human immunodeficiency virus infection occurring in Hong Kong.