Genetically modified foods and allergy.

2015 marked the 25th anniversary of the commercial use and availability of genetically modified crops. The area of planted biotech crops cultivated globally occupies a cumulative two billion hectares, equivalent to twice the land size of China or the United States. Foods derived from genetically modified plants are widely consumed in many countries and genetically modified soybean protein is extensively used in processed foods throughout the industrialised countries. Genetically modified food technology offers a possible solution to meet current and future challenges in food and medicine. Yet there is a strong undercurrent of anxiety that genetically modified foods are unsafe for human consumption, sometimes fuelled by criticisms based on little or no firm evidence. This has resulted in some countries turning away food destined for famine relief because of the perceived health risks of genetically modified foods. The major concerns include their possible allergenicity and toxicity despite the vigorous testing of genetically modified foods prior to marketing approval. It is imperative that scientists engage the public in a constructive evidence-based dialogue to address these concerns. At the same time, improved validated ways to test the safety of new foods should be developed. A post-launch strategy should be established routinely to allay concerns. Mandatory labelling of genetically modified ingredients should be adopted for the sake of transparency. Such ingredient listing and information facilitate tracing and recall if required.

Effect of the CYP3A5 and ABCB1 genotype on exposure, clinical response and manifestation of toxicities from sunitinib in Asian patients.

The objective of this study was to determine the effect of the CYP3A5 and ATP binding cassette subfamily B member 1 (ABCB1) single-nucleotide polymorphisms on the disposition of sunitinib and SU12662, on clinical response, and on the manifestation of toxicities in Asian metastatic renal cell carcinoma patients. At week 4 of each treatment cycle, toxicities and plasma steady-state levels were assessed. Clinical response was assessed after two cycles. Genotyping was performed by using the PCR restriction fragment length polymorphism method. The CC genotype for ABCB1 was associated with a higher sunitinib exposure (76.81 vs 56.55 ng ml(-1), P=0.03), higher risk of all-grade rash (RR 3.00, 95% CI 1.17-7.67) and mucositis (RR 1.60, 95% CI 1.10-2.34) and disease progression than compared with the CT/TT genotype. There was a lack of association observed between the CYP3A5 polymorphism and exposure, response and toxicities. The polymorphism of ABCB1 (C3435T) has an important role in the manifestation of toxicities and drug exposure, but not polymorphism of CYP3A5.

Association of proinflammatory cytokines and chemotherapy-associated cognitive impairment in breast cancer patients: a multi-centered, prospective, cohort study.

BACKGROUND: Existing evidence suggests that proinflammatory cytokines play an intermediary role in postchemotherapy cognitive impairment. This is one of the largest multicentered, cohort studies conducted in Singapore to evaluate the prevalence and proinflammatory biomarkers associated with cognitive impairment in breast cancer patients. PATIENTS AND METHODS: Chemotherapy-receiving breast cancer patients (stages I-III) were recruited. Proinflammatory plasma cytokines concentrations [interleukin (IL)-1ß, IL-2, IL-4, IL-6, IL-8, IL-10, granulocyte-macrophage colony-stimulating factor, interferon-γ and tumor necrosis factor-α] were evaluated at 3 time points (before chemotherapy, 6 and 12 weeks after chemotherapy initiation). The FACT-Cog (version 3) was utilized to evaluate patients' self-perceived cognitive disturbances and a computerized neuropsychological assessment (Headminder) was administered to evaluate patients' memory, attention, response speed and processing speed. Changes of cognition throughout chemotherapy treatment were compared against the baseline. Linear mixed-effects models were applied to test the relationships of clinical variables and cytokine concentrations on self-perceived cognitive disturbances and each objective cognitive domain. RESULTS: Ninety-nine patients were included (age 50.5 ± 8.4 years; 81.8% Chinese; mean duration of education = 10.8 ± 3.3 years). Higher plasma IL-1ß was associated with poorer response speed performance (estimate: -0.78; 95% confidence interval (CI) -1.34 to -0.03; P = 0.023), and a higher concentration of IL-4 was associated with better response speed performance (P = 0.022). Higher concentrations of IL-1ß and IL-6 were associated with more severe self-perceived cognitive disturbances (P = 0.018 and 0.001, respectively). Patients with higher concentrations of IL-4 also reported less severe cognitive disturbances (P = 0.022). CONCLUSIONS: While elevated concentrations of IL-6 and IL-1ß were observed in patients with poorer response speed performance and perceived cognitive disturbances, IL-4 may be protective against chemotherapy-associated cognitive impairment. This study is important because cytokines would potentially be mechanistic mediators of chemotherapy-associated cognitive changes.

Allergy in Hong Kong: an unmet need in service provision and training.

Many children in Hong Kong have allergic diseases and epidemiological data support a rising trend. Only a minority of children will grow out of their allergic diseases, so the heavy clinical burden will persist into adulthood. In an otherwise high-quality health care landscape in Hong Kong, allergy services and training are a seriously unmet need. There is one allergy specialist for 1.5 million people, which is low not only compared with international figures, but also compared with most other specialties in Hong Kong. The ratio of paediatric and adult allergists per person is around 1:460 000 and 1:2.8 million, respectively, so there is a severe lack of adult allergists, while the paediatric allergists only spend a fraction of their time working with allergy. There are no allergists and no dedicated allergy services in adult medicine in public hospitals. Laboratory support for allergy and immunology is not comprehensive and there is only one laboratory in the public sector supervised by accredited immunologists. These findings clearly have profound implications for the profession and the community of Hong Kong and should be remedied without delay. Key recommendations are proposed that could help bridge the gaps, including the creation of two new pilot allergy centres in a hub-and-spoke model in the public sector. This could require recruitment of specialists from overseas to develop the process if there are no accredited allergy specialists in Hong Kong who could fulfil this role.

Developing FGFR4 inhibitors as potential anti-cancer agents via in silico design, supported by in vitro and cell-based testing.

Fibroblast growth factor receptor-4 (FGFR4) is a tyrosine kinase with a range of important physiological functions. However, it is also frequently mutated in various cancers and is now generating significant interest as a potential therapeutic target. Unfortunately, biochemical characterization of its role in disease, and further evaluation as a drug target is hampered by lack of a specific inhibitor. We aimed to discover new inhibitors for FGFR4 ab initio using a strategy combining in silico, in vitro and cell-based assays. We used the homologous FGFR1 to calculate docking scores of a chemically-diverse library of approximately 2000 potential kinase inhibitors. Nineteen potential inhibitors and ten randomly- selected negative controls were taken forward for in vitro FGFR4 kinase assays. All compounds with good docking scores significantly inhibited FGFR4 kinase activity, some with sub-micromolar (most potent being V4-015 with an IC(50) of 0.04 µM). Four of these compounds also demonstrated substantial activity in cellular assays using the FGFR4- overexpressing breast carcinoma cell line, MDA-MB453. Through immunoblot assays, these compounds were shown to block the phosphorylation of the FGFR4 adaptor protein, FGFR substrate protein-2α (FRS2α). The most potent compound to date, V4-015, suppressed proliferation of MDA-MB453 cells at sub-micromolar concentrations, activated the pro-apoptotic caspases 3/7 and inhibited cellular migration. While achieving complete selectivity of this compound for FGFR4 will require further lead optimization, this study has successfully identified new chemical scaffolds with unprecedented FGFR4 inhibition capacities that will support mechanism of action studies and future anti-cancer drug design.

The FGFR4 Y367C mutant is a dominant oncogene in MDA-MB453 breast cancer cells.

Mutational analysis of oncogenes is critical for our understanding of cancer development. Oncogenome screening has identified a fibroblast growth factor receptor 4 (FGFR4) Y367C mutation in the human breast cancer cell line MDA-MB453. Here, we investigate the consequence of this missense mutation in cancer cells. We show that MDA-MB453 cells harbouring the mutation are insensitive to FGFR4-specific ligand stimulation or inhibition with an antagonistic antibody. Furthermore, the FGFR4 mutant elicits constitutive phosphorylation leading to an activation of the mitogen-activated protein kinase cascade as shown by an enhanced Erk1/2 phosphorylation. Cloning and ectopic expression of the FGFR4 Y367C mutant in HEK293 cells revealed high pErk levels and enhanced cell proliferation. Based on these findings, we propose that FGFR4 may be a driver of tumour growth, particularly when highly expressed or stabilized and constitutively activated through genetic alterations. As such, FGFR4 presents an option for further mutational screening in tumours and is an attractive cancer target with the therapeutic potential.

Congenital Rosai-Dorfman disease presenting with anemia, thrombocytopenia, and hepatomegaly.

Rosai-Dorfman disease (RDD) is a rare entity of non-Langerhans cell histiocytoses (non-LCH) which usually presents with bilateral painless cervical lymphadenopathy. We describe a neonate with RDD who presented with anemia, thrombocytopenia and hepatomegaly. He recovered spontaneously with conservative management. This represents an atypical presentation of RDD. Conservative management with close monitoring can be adopted for some with systemic involvement.

ADMA regulates angiogenesis: genetic and metabolic evidence.

Endothelium-derived nitric oxide (NO) plays an important role in transducing the effects of angiogenic factors. Asymmetric dimethylarginine (ADMA) is an endogenous inhibitor of NO synthase (NOS). We used a murine model of hindlimb ischemia to investigate whether genetic or metabolic changes in ADMA levels could impair angiogenic response in vivo. Hindlimb ischemia was surgically induced in C57BL/6J mice, apo E-deficient mice, or transgenic mice overexpressing dimethylarginine dimethylaminohydrolase (DDAH). Some animals were also treated with the NOS antagonist L-nitro-arginine, or the NO precursor L-arginine. Angiogenesis was quantified in the hindlimb skeletal muscle by capillary/myocyte ratio. Plasma or tissue ADMA levels were measured by HPLC. In normal mice, hindlimb ischemia increased tissue ADMA twofold, and reduced DDAH and NOS expression. This was associated with a reduced NOS activity (by over 80%) three days following surgery. On day seven, a threefold increase in DDAH expression and a fall in tissue ADMA levels were associated with a sevenfold increase in NOS activity, whereas NOS expression did not increase above baseline. In DDAH transgenic mice, the elevation of ADMA and decrement in NOS activity was blunted during hindlimb ischemia. Plasma ADMA levels were increased in apo E-mice (1.79 +/- 0.45 versus 1.07 +/- 0.08 pmol/l; p = 0.008). Capillary index was significantly reduced in apo E-mice up to seven weeks after surgery (0.25 +/- 0.05 versus 0.62 +/- 0.08; p < 0.001). The effect of hypercholesterolemia on capillary index was reversed by L-arginine, and (in wild-type mice) mimicked by administration of the NOS antagonist L-nitro-arginine. In conclusion, metabolic or genetic changes in plasma and tissue ADMA levels affect tissue NO production and angiogenic response to ischemia.

Primary immunodeficiency in Hong Kong and the use of genetic analysis for diagnosis.

OBJECTIVES: To review the management of primary immunodeficiency and discuss recent advances in genetic analysis. DESIGN: Retrospective study. SETTING: University teaching hospital, Hong Kong. PATIENTS: Children diagnosed with primary immunodeficiency and followed up in the immunology clinic during the period 1988 to 2003. MAIN OUTCOME MEASURES: Demographic data, co-morbidities and treatment of patients, outcome and complications; identification of disease by genetic mutations. RESULTS: Medical records of a total of 117 patients (72 male, 45 female) diagnosed with primary immunodeficiency in the Department of Paediatrics and Adolescent Medicine, Queen Mary Hospital, Hong Kong during the past 15 years (1988-2003) were reviewed. All patients were followed up in the immunology clinic. Some patients had been referred from the private sector or other hospitals for immunological workup. Six categories of primary immunodeficiency were identified: predominantly humoral defect (n=50), predominantly cellular defect (n=22), combined humoral and cellular defect (n=5), phagocytic defect (n=18), complement disorders (n=4), and others (n=18). Although infection was the underlying cause of most co-morbidities and mortality, autoimmune (n=7) and allergic (n=23) manifestations were common. In addition, three patients developed lymphoma. Recent advances in the genetic diagnosis of several types of primary immunodeficiency were also reviewed: X-linked Wiskott-Aldrich syndrome, X-linked chronic granulomatous disease, X-linked agammaglobulinaemia, X-linked lymphoproliferative syndrome, leukocyte adhesion disease type I, and X-linked hyperimmunoglobulin M syndrome. This provides an invaluable means of understanding the molecular basis of primary immunodeficiency and has important clinical applications. CONCLUSIONS: Co-morbidities like autoimmune disease and allergic disease are common in patients with primary immunodeficiency and should be carefully evaluated. Likewise, a diagnosis of primary immunodeficiency should be considered when evaluating patients with these conditions. Rapid progress in the field of molecular genetics will enable definite and early diagnosis, and more importantly, potential curative therapy to be administered.

Chronic benign neutropenia among Chinese children.

OBJECTIVE: To delineate the clinical behaviour of chronic benign neutropenia in Chinese children in Hong Kong. DESIGN: Retrospective study. SETTING: University teaching hospital, Hong Kong. PATIENTS: All infants and children with absolute neutrophil count of 1.5 x 10(9) /L or lower for more than 3 months. MAIN OUTCOME MEASURES: Development of significant infection, and achievement of remission. RESULTS: Twenty-four children with chronic benign neutropenia were identified between 1992 and 2001. Their median age of diagnosis was 9 months. The mean (standard deviation) initial absolute neutrophil count was 0.28 x 10(9) /L (0.24 x 10(9) /L). Twenty-three patients presented with infection. Of the 19 patients tested, four (21%) were positive for anti-neutrophil antibodies. Bone marrow examination was performed in 17 patients: nine had normal results, but six showed evidence of peripheral consumption, one showed late maturation arrest at band stage, and one showed phagocytosis of myeloid cells by histiocytes. The overall hospitalised infection rate was 51.6 episodes per 1000 patient-months. Ten percent of cases were considered 'significant' infections and required hospital admission with either surgical intervention or intravenous therapy (antibiotics or fluid replacement). In the first year of diagnosis, more than 80% of patients had their lowest absolute neutrophil count (mean, 0.16 x 10(9) /L; standard deviation, 0.11 x 10(9) /L). Granulocyte-colony stimulating factor was used to treat three patients and induced transient elevation of absolute neutrophil count in all three. The projected remission rate was 55.4% at 3 years. Even for those with persistent disease, there was significant recovery in absolute neutrophil count to a mean of 0.5 x 10(9) /L (P<0.01). CONCLUSIONS: Patients with chronic benign neutropenia experienced a relatively benign clinical course regardless of their remission status. Only a small proportion of patients developed significant infections. A multi-centre prospective study may help identify predictive factors of remission.

Klebsiella infection in patients with thalassemia.

Klebsiella infection has previously been reported in a few patients with transfusion-dependent thalassemia. The incidence and clinical spectrum of this infection in our cohort of patients were reviewed retrospectively. Among 160 patients observed for 12 years, there were 15 episodes of Klebsiella infection that occurred in 12 patients (7.5%), resulting in an incidence of 0.78 infections per 100 patient-years. The clinical spectrum included sinusitis (4 cases), intracranial infection (5 cases), septicemia (4 cases), and abscesses of the liver, lung, kidney, and parotid gland (1 case each). Three patients had recurrent infections involving different sites, 2 (16%) died of fulminant septicemia, and 3 (25%) had significant permanent neurological deficits. The antibiotic susceptibility pattern for the isolates was similar to the pattern for isolates recovered in the community. With regard to predisposing factors, iron overload and liver function derangement were found to be significant on univariate analysis (P=.046 and P=.049, respectively) but insignificant on multivariate analysis. Klebsiella infection was a serious and frequently encountered complication in our patients with transfusion-dependent thalassemia, resulting in high mortality and morbidity rates.

Public awareness of diabetes mellitus in Singapore.

INTRODUCTION: Much effort has been devoted to educating the public about diabetes. However, the impact of such efforts has yet to be formally evaluated. OBJECTIVES: To identify areas of knowledge that might require additional educational efforts. METHODOLOGY: A cross-sectional survey was conducted to evaluate the general public's knowledge of diabetes. The respondents were required to answer 45 questions from a pre-tested questionnaire divided into five main sections, namely, general knowledge, risk factors, symptoms and complications, treatment and management, monitoring and other miscellaneous questions. A point was awarded for each correct response and zero for wrong or unsure responses. The maximum total score was 41. The miscellaneous questions were not scored. RESULTS: A total of 1337 subjects were interviewed. The mean score obtained by the respondents was 66.1% of the maximum possible total score (i.e. 27.1 points out of 41). The "correct answer" percentages for the individual questions from each section ranges from 22 to 83% (General knowledge), 31 to 91% (Risk factors), 48 to 81% (Symptoms and complications), 35 to 87% (Treatment and management), and 58 to 93% (Monitoring of condition).With respect to the source of medical information, health care professionals did not feature prominently (20.7%). CONCLUSION: The public as represented by the samples in this survey is generally well informed about diabetes except for a few areas. Analysis of these areas would have a significant implication for future public education programme. Health care professionals should be more proactive in disseminating health information about diabetes to the public.

Differential expression of nitric oxide by dermal microvascular endothelial cells from patients with scleroderma.

Vascular abnormalities in scleroderma are fundamental to the pathogenesis of this disease. The objective of this study was to characterize dermal microvascular endothelial cells (DMEC) isolated from scleroderma patients with respect to growth and expression of the constitutive form of endothelial nitric oxide synthase (eNOS). DMEC from patients with both systemic sclerosis (SSc) and localized scleroderma (Loc Scl) contained small intact microvascular structures in contrast to single cell isolations obtained from control skin. Immunoaffinity selection on anti-PECAM-1 beads yielded pure populations of DMEC expressing normal markers. While the morphology and initial growth of SSc DMEC closely paralleled control cells, the growth of SSc DMEC decreased with time in culture (doubling time of 3 days vs. 5 days). Expression of ecNOS mRNA was reduced in both Loc Scl and SSc as shown by semi-quantitative RT-PCR (p < 0.001). Western blots showed variable but generally lower ecNOS protein levels and decreased levels of nitrogen oxides in media were found from both SSc and Loc Scl relative to control cells. The results indicate an intrinsic defect in the mechanism of nitric oxide production in DMEC isolated from scleroderma patients and suggest its possible involvement in the pathophysiology of scleroderma.