SSTR2 in Nasopharyngeal Carcinoma: Relationship with Latent EBV Infection and Potential as a Therapeutic Target

Nasopharyngeal carcinoma (NPC) is a malignant epithelial tumor, most commonly located in the pharyngeal recess and endemic to parts of Asia. It is often detected at a late stage which is associated with poor prognosis (5-year survival rate of 63%). Treatment for this malignancy relies predominantly on radiotherapy and/or systemic chemotherapy, which can be associated with significant morbidity and impaired quality of life. In endemic regions NPC is associated with infection by Epstein-Barr virus (EBV) which was shown to upregulate the somatostatin receptor 2 (SSTR2) cell surface receptor. With recent advances in molecular techniques allowing for an improved understanding of the molecular aetiology of this disease and its relation to SSTR2 expression, we provide a comprehensive and up-to-date overview of this disease and highlight the emergence of SSTR2 as a key tumor biomarker and promising target for imaging and therapy.

Abstract LB098: Vulnerability of MTAP-deleted nasopharyngeal carcinoma to MAT2A inhibition

Nasopharyngeal carcinoma (NPC) is an EBV-associated cancer prevalent in Southern China and Southeast Asia. We have generated a comprehensive genomic profile of NPC using whole-genome sequencing (WGS) and established a catalogue of somatic alterations of this EBV-associated cancer. In addition to the significantly mutated genes reported in previous WES studies, our WGS study revealed recurrent structural variants (SVs) and copy number variants (CNVs) driving key oncogenic pathways, including cell cycle, NF-kappaB and TGF-beta signaling. While immediately druggable gene aberrations (e.g. PIK3CA mutations and FGFR3-TACC3 fusions) are found in only ~3-5% of NPC, a synthetic lethality-based target, homozygous deletion of MTAP defined by fine-mapping of CDKN2A/CDKN2B deletion breakpoints at chromosome 9p21.3 was frequently detected (34%). Notably, the study has also revealed mutual exclusivity among tumors with MTAP deletion and TP53 alterations (p=0.022). Loss of MTAP has further been validated in a cohort of advanced and recurrent tumors (16/50, 32%) by FISH analysis and immunohistochemistry staining. The high prevalence and clonal nature of MTAP deletion in NPC implicate synthetic lethal targeting of MTAP-deleted tumors as a potential precision treatment for NPC patients. Using a CRISPR-based MTAP-knockout cell line and MTAP-deleted patient derived xenograft (PDX), we revealed that MAT2A and PRMT5 inhibition selectively suppressed growth of MTAP-deleted NPC. Treatment with MAT2A inhibitor, FIADS-5, led to depleted PRMT5 activity and reduced symmetric arginine methylation (SAMe) in these in vitro and in vivo NPC models. In addition to selective growth inhibition, MAT2A inhibition also targeted various unique oncogenic properties in NPC. The FIADS-5 treatment was shown to induce TP53 and BAX expression, cellular differentiation and keratinization in these MTAP-deleted NPC. Our findings demonstrated the translational potential of targeting MTAP-deletion in this EBV-associated epithelial cancer.

Citation Format: Yuk Yu Chan, Jeff P. Bruce, Vivian W.Y. Lui, Grace T. Y. Chung, Sai-Wah Tsao, Ka-Fai To, Trevor J. Pugh, Kwok-Wai Lo. Vulnerability of MTAP-deleted nasopharyngeal carcinoma to MAT2A inhibition [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr LB098.

A rare and unusual cause of Vibrio cholerae non-O1, non-O139 causing spontaneous peritonitis in a patient with cirrhosis

Spontaneous bacterial peritonitis caused by Vibrio cholerae non-O1/ non-O139 is a rare phenomenon. V. cholerae is known as a common aetiology of epidemic diarrheal disease and rarely causes extra-gastrointestinal infections. In this report, a 52-year-old man presented to our hospital with a clinical scenario for chronic liver cirrhosis with low grade fever and loose stools. V. cholerae was isolated from peritoneal fluid culture, which was further confirmed as non-O1/ non-O139 strain by multiplex polymerase chain reaction. The patient was successfully treated with antimicrobial therapy and peritoneal drainage. This case represents the first isolation of V. cholerae non-O1/ non-O139 strain from peritoneal fluid.

Somatostatin receptor 2 expression in nasopharyngeal cancer is induced by Epstein Barr virus infection: impact on prognosis, imaging and therapy

Nasopharyngeal cancer (NPC), endemic in Southeast Asia, lacks effective diagnostic and therapeutic strategies. Even in high-income countries the 5-year survival rate for stage IV NPC is less than 40%. Here we report high somatostatin receptor 2 (SSTR2) expression in multiple clinical cohorts comprising 402 primary, locally recurrent and metastatic NPCs. We show that SSTR2 expression is induced by the Epstein-Barr virus (EBV) latent membrane protein 1 (LMP1) via the NF-κB pathway. Using cell-based and preclinical rodent models, we demonstrate the therapeutic potential of SSTR2 targeting using a cytotoxic drug conjugate, PEN-221, which is found to be superior to FDA-approved SSTR2-binding cytostatic agents. Furthermore, we reveal significant correlation of SSTR expression with increased rates of survival and report in vivo uptake of the SSTR2-binding 68Ga-DOTA-peptide radioconjugate in PET-CT scanning in a clinical trial of NPC patients (NCT03670342). These findings reveal a key role in EBV-associated NPC for SSTR2 in infection, imaging, targeted therapy and survival.

Receptor tyrosine kinase fusions act as a significant alternative driver of the serrated pathway in colorectal cancer development

Serrated polyps are a clinically and molecularly heterogeneous group of lesions that can contribute to the development of colorectal cancers (CRCs). However, the molecular mechanism underlying the development of serrated lesions is still not well understood. Here, we combined multiple approaches to analyze the genetic alterations in 86 colorectal adenomas (including 35 sessile serrated lesions, 15 traditional adenomas, and 36 conventional adenomatous polyps). We also investigated the in vitro and in vivo oncogenic properties of a novel variant of the NCOA4-RET fusion gene. Molecular profiling revealed that sessile serrated lesions and traditional serrated adenomas have distinct clinicopathological and molecular features. Moreover, we identified receptor tyrosine kinase translocations exclusively in sessile serrated lesions (17%), and the observation was validated in a separate cohort of 34 sessile serrated lesions (15%). The kinase fusions as well as the BRAF and KRAS mutations were mutually exclusive to each other. Ectopic expression of a novel variant of the NCOA4-RET fusion gene promoted cell proliferation in vitro and in vivo, and the proliferation was significantly suppressed by RET kinase inhibitors. All of these underscored the importance of mitogen-activated protein kinase (MAPK) pathway activation in the serrated pathway of colorectal tumorigenesis. In addition, we demonstrated that the kinase fusion may occur early in the precursor lesion and subsequent loss of TP53 may drives the transformation to carcinoma during serrated tumorigenesis. In conclusion, we identified kinase fusions as a significant alternative driver of the serrated pathway in colorectal cancer development, and detecting their presence may serve as a biomarker for the diagnosis of sessile serrated lesions. © 2020 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Development and validation of TaqMan real-time PCR for the detection of Burkholderia pseudomallei isolates from Malaysia

Rapid detection of Burkholderia pseudomallei, the etiologic agent of melioidosis, allows for timely initiation of appropriate treatment and better clinical outcomes. In the current gold standard, the culture method is time consuming and suffers from low sensitivity. Meanwhile, previously reported molecular assays are fast and sensitive, but their performance on isolates from Malaysia, an endemic region of melioidosis is under reported. This study designed oligonucleotides targeting orf2 of Type III secretion system (TTSS) genes cluster for the detection of Malaysian B. pseudomallei isolates and evaluated the assay on 95 local B. pseudomallei strains, 58 other microorganisms and 71 clinical specimens from patients. The developed assay exclusively detected all tested B. pseudomallei isolates with a detection limit of 20 fg per reaction (equivalent to ~2.5 copies). Subsequent testing on clinical samples showed that the assay detected all confirmed specimens with the growth of B. pseudomallei (n = 10/10). None of the negative specimens had a detectable signal of our TTSS-orf2 assay (n = 0/61). In conclusion, the present study provides crucial preliminary data for a subsequent study and should be considered as a potential alternative to current time-consuming culture method for the detection of B. pseudomallei.

Validity of screening tools for dementia and mild cognitive impairment among the elderly in primary health care: a systematic review

OBJECTIVES

This systematic review aims to provide updated and comprehensive evidence on the validity and feasibility of screening tools for mild cognitive impairment (MCI) and dementia among the elderly at primary healthcare level.

STUDY DESIGN

A review of articles was performed.

METHODS

A search strategy was used by using electronic bibliographic databases including PubMed, Embase and CENTRAL for published studies and reference list of published studies. The articles were exported to a bibliographic database for further screening process. Two reviewers worked independently to screen results and extract data from the included studies. Any discrepancies were resolved and confirmed by the consensus of all authors.

RESULTS

There were three screening approaches for detecting MCI and dementia - screening by a healthcare provider, screening by a self-administered questionnaire and caretaker informant screening. Montreal Cognitive Assessment (MoCA) was the most common and preferable tool for MCI screening (sensitivity [Sn]: 81-97%; specificity [Sp]: 60-86%), whereas Addenbrooke's Cognitive Examination (ACE) was the preferable tool for dementia screening (Sn: 79-100%; Sp: 86%).

CONCLUSION

This systematic review found that there are three screening approaches for detecting early dementia and MCI at primary health care. ACE and MoCA are recommended tools for screening of dementia and MCI, respectively.

Validity of self-reported weight and height: a cross-sectional study among Malaysian adolescents

Background

Self-reported weight and height are commonly used in lieu of direct measurements of weight and height in large epidemiological surveys due to inevitable constraints such as budget and human resource. However, the validity of self-reported weight and height, particularly among adolescents, needs to be verified as misreporting could lead to misclassification of body mass index and therefore overestimation or underestimation of the burden of BMI-related diseases. The objective of this study was to determine the validity of self-reported weight and height among Malaysian secondary school children.

Methods

Both self-reported and directly measured weight and height of a subgroup of 663 apparently healthy schoolchildren from the Malaysian Adolescent Health Risk Behaviour (MyAHRB) survey 2013/2014 were analysed. Respondents were required to report their current body weight and height via a self-administrative questionnaire before they were measured by investigators. The validity of self-reported against directly measured weight and height was examined using intraclass correlation coefficient (ICC), the Bland-Altman plot and weighted Kappa statistics.

Results

There was very good intraclass correlation between self-reported and directly measured weight [r = 0.96, 95% confidence interval (CI): 0.93, 0.97] and height (r = 0.94, 95% CI: 0.90, 0.96). In addition the Bland-Altman plots indicated that the mean difference between self-reported and direct measurement was relatively small. The mean difference (self-reported minus direct measurements) was, for boys: weight, −2.1 kg; height, −1.6 cm; BMI, −0.44 kg/m² and girls: weight, −1.2 kg; height, −0.9 cm; BMI, −0.3 kg/m². However, 95% limits of agreement were wide which indicated substantial discrepancies between self-reported and direct measurements method at the individual level. Nonetheless, the weighted Kappa statistics demonstrated a substantial agreement between BMI status categorised based on self-reported weight and height and the direct measurements (kappa = 0.76, 95% CI: 0.67, 0.84).

Conclusion

Our results show that the self-reported weight and height were consistent with direct measurements and therefore can be used in assessing the nutritional status of Malaysian school children from the age of 13 to 17 years old in epidemiological studies and for surveillance purposes when direct measurements are not feasible, but not for assessing nutritional status at the individual level.

The prevalence of physical activity and its associated factors among Malaysian adults: findings from the National Health and Morbidity Survey 2011

OBJECTIVES

Despite the health-enhancing benefits of physical activity, a large segment of the Malaysian population does not engage in regular physical activity at the recommended level. This study aimed to determine physical activity patterns and the associated sociodemographic correlates of physical activity.

STUDY DESIGN

Data on physical activity were obtained from the National Health and Morbidity Survey (NHMS) 2011, a nationally representative, population-based cross-sectional study. A two-stage stratified sampling method was used to select a representative sample of Malaysian adults aged 16 years and above.

METHODS

A total of 19,145 adults aged 16 years and above were recruited, and face-to-face interviews were conducted using the International Physical Activity Questionnaire (IPAQ), short version. The correlates for physical activity were identified using multivariate analysis.

RESULTS

In this study, 64.3% (95%CI: 63.1-65.5) of Malaysian adults aged 16 and above were physically active, but overall physical activity levels decreased with advancing age. Men, rural residents, 'other' ethnic groups, and married women were more likely to demonstrate higher levels of physical activity.

CONCLUSION

Approximately 65% of Malaysian adults were physically active. However, it is recommended that health promotions for active lifestyles should be targeted to the least active segments, which constitute more than a quarter of the Malaysian population.

A secular increase in BMD in Chinese women

Population-based studies have revealed a decline in the incidence of age-adjusted hip fractures in southern Chinese women during the past decade. To determine whether there was a secular change in population characteristics that accounted for this decline, we compared the bone mineral density (BMD) and lifestyle habits of two cohorts of women who were more than 50 years of age and who were recruited from 1995 to 2000 and 2005 to 2010. The BMD levels in the 2005-2010 cohort were significantly higher at the spine and hip and ranged from 3.6 to 17.8% among the different age groups. Additionally, a significantly lower prevalence of subjects with osteoporosis and osteopenia was observed. Longer reproductive years, higher levels of physical activity, higher estradiol and 25(OH) vitamin D levels, and lower alkaline phosphatase levels were found in the 2005-2010 cohort. After adjusting for bone-determining factors, significant differences were detected in the BMD levels at the lumbar spine, femoral neck, and total hip (4.17, 9.02, and 9.34%, respectively) in women >50 years of age but not in women ≤50 years of age. The secular increase in BMD and healthier lifestyles most likely led to the decline in the incidence of age-adjusted fractures.

Inhibitory effects of Sargassum polycystum on tyrosinase activity and melanin formation in B16F10 murine melanoma cells

ETHNOPHARMACOLOGICAL RELEVANCE

Sargassum polycystum, a type of brown seaweed, has been used for the treatment of skin-related disorders in traditional medicine.

AIM OF THE STUDY

The aim of the present study is to investigate the antimelanogenesis effect of Sargassum polycystum extracts by cell-free mushroom tyrosinase assay followed by cell viability assay, cellular tyrosinase assay and melanin content assay using B16F10 murine melanoma cells.

MATERIALS AND METHODS

Sargassum polycystum was extracted with 95% ethanol and further fractionated with hexane, ethyl acetate and water. The ethanolic crude extract and its fractionated extracts were tested for their potential to act as antimelanogenesis or skin-whitening agents by their abilities to inhibit tyrosinase activity in the cell-free mushroom tyrosinase assay and cellular tyrosinase derived from melanin-forming B16F10 murine melanoma cells. The tyrosinase inhibitory activity was correlated to the inhibition of melanin production in α-MSH-stimulated and unstimulated B16F10 cells.

RESULTS

Sargassum polycystum ethanolic extract and its fractions had little or no inhibitory effect on mushroom tyrosinase activity. However, when tested on cellular tyrosinase, the ethanolic extract and its non-polar fraction, hexane fraction (SPHF), showed significant inhibition of cellular tyrosinase activity. In parallel to its cellular tyrosinase inhibitory activity, SPHF was also able to inhibit basal and α-MSH-stimulated melanin production in B16F10 cells.

CONCLUSIONS

Our findings showed that (i) cellular tyrosinase assay is more reliable than mushroom tyrosinase assay in the initial testing of potential antimelanogenesis agents and, (ii) SPHF inhibited melanogenesis by inhibiting cellular tyrosinase activity. SPHF may be useful for treating hyperpigmentation and as a skin-whitening agent in cosmetics industry.

Reproductive outcomes in women with congenital uterine anomalies: a systematic review

OBJECTIVE

Congenital uterine anomalies are common but their effect on reproductive outcome is unclear. We conducted a systematic review to evaluate the association between different types of congenital uterine anomaly and various reproductive outcomes.

METHODS

Searches were performed using MEDLINE, EMBASE, the Cochrane Library and Web of Science. The Newcastle-Ottawa Quality Assessment Scale was used for quality assessment. Uterine defects were grouped into arcuate uteri, canalization defects (septate and subseptate uteri) and unification defects (unicornuate, bicornuate and didelphys uteri). Pooled risk ratios (RR) with 95% confidence intervals (CI) were computed using random effects models.

RESULTS

We identified nine studies comprising 3805 women. Meta-analysis showed that arcuate uteri were associated with increased rates of second-trimester miscarriage (RR, 2.39; 95% CI, 1.33-4.27, P = 0.003) and fetal malpresentation at delivery (RR, 2.53; 95% CI, 1.54-4.18; P < 0.001). Canalization defects were associated with reduced clinical pregnancy rates (RR, 0.86; 95% CI, 0.77-0.96; P = 0.009) and increased rates of first-trimester miscarriage (RR, 2.89; 95% CI; 2.02-4.14; P < 0.001), preterm birth (RR, 2.14; 95% CI, 1.48-3.11; P < 0.001) and fetal malpresentation (RR, 6.24; 95% CI, 4.05-9.62; P < 0.001). Unification defects were associated with increased rates of preterm birth (RR, 2.97; 95% CI, 2.08-4.23; P < 0.001) and fetal malpresentation (RR, 3.87; 95% CI, 2.42-6.18; P < 0.001).

CONCLUSIONS

Canalization defects reduce fertility and increase rates of miscarriage and preterm delivery. None of the unification defects reduces fertility but some are associated with miscarriage and preterm delivery. Arcuate uteri are specifically associated with second-trimester miscarriage. All uterine anomalies increase the chance of fetal malpresentation at delivery.

The prevalence of congenital uterine anomalies in unselected and high-risk populations: a systematic review

BACKGROUND

The prevalence of congenital uterine anomalies in high-risk women is unclear, as several different diagnostic approaches have been applied to different groups of patients. This review aims to evaluate the prevalence of such anomalies in unselected populations and in women with infertility, including those undergoing IVF treatment, women with a history of miscarriage, women with infertility and recurrent miscarriage combined, and women with a history of preterm delivery.

METHODS

Searches of MEDLINE, EMBASE, Web of Science and the Cochrane register were performed. Study selection and data extraction were conducted independently by two reviewers. Studies were grouped into those that used ‘optimal’ and ‘suboptimal’ tests for uterine anomalies. Meta-analyses were performed to establish the prevalence of uterine anomalies and their subtypes within the various populations.

RESULTS

We identified 94 observational studies comprising 89 861 women. The prevalence of uterine anomalies diagnosed by optimal tests was 5.5% [95% confidence interval (CI), 3.5–8.5] in the unselected population, 8.0% (95% CI, 5.3–12) in infertile women, 13.3% (95% CI, 8.9–20.0) in those with a history of miscarriage and 24.5% (95% CI, 18.3–32.8) in those with miscarriage and infertility. Arcuate uterus is most common in the unselected population (3.9%; 95% CI, 2.1–7.1), and its prevalence is not increased in high-risk groups. In contrast, septate uterus is the most common anomaly in high-risk populations.

CONCLUSIONS

Women with a history of miscarriage or miscarriage and infertility have higher prevalence of congenital uterine anomalies compared with the unselected population.

Prevalence of uterine anomalies and their impact on early pregnancy in women conceiving after assisted reproduction treatment

OBJECTIVE

To estimate the prevalence of congenital uterine anomalies in subfertile women and to evaluate their influence on early pregnancy following assisted reproduction treatment (ART).

METHODS

We prospectively recruited 1402 subjects undergoing ART over a period of 5 years from 2005 to 2009. Three-dimensional transvaginal sonography was performed in the early follicular phase of the menstrual cycle (days 2-5) and repeated in the late follicular phase (days 10-14) if the shape of the uterine cavity could not be assessed at the first scan. All subjects who conceived following ART were followed up to 12 weeks' gestation. Chi-square test was used to compare the pregnancy rates and miscarriage rates between women shown to have uterine anomalies and those with a normal uterus.

RESULTS

One thousand three hundred and eighty-five subjects were included for final analysis after excluding 17 subjects in whom a definitive diagnosis could not be made. While 1201 (86.7%) subjects had a normal uterine cavity, uterine anomalies were demonstrated in 184 (13.3%) subjects. Arcuate uteri represented the commonest anomaly (n = 164 (11.8%)) followed by septate (n = 7 (0.5%)), unicornuate (n = 6 (0.4%)), subseptate (n = 5 (0.4%)), bicornuate (n = 1 (0.1%)) and T-shaped uteri (n = 1 (0.1%)). A total of 440 subjects who underwent ART were followed up. The pregnancy rates in women with arcuate uteri (36/66 (54.5%)) and major uterine anomalies (7/10 (70.0%)) were statistically similar (P = 0.09 and P = 0.11, respectively) to that of the matched controls with normal uteri (158/364 (43.4%)). While first-trimester miscarriage rates were similar (P = 0.81) between the control group (20/158 (12.7%)) and women with arcuate uteri (5/36 (13.9%)), women with major uterine anomalies experienced a higher miscarriage rate (3/7 (42.9%); P = 0.05).

CONCLUSIONS

Women who are referred for ART have a high prevalence of congenital uterine anomalies, the most common anomaly being an arcuate uterus. These anomalies are not associated with a reduction in pregnancy rates following ART. However, while the arcuate uterus was not associated with an increase in first-trimester miscarriage, major uterine anomalies seemed to increase the risk of first-trimester miscarriage.

Genetic polymorphisms of Chinese patients with ischemic stroke and concurrent stenoses of extracranial and intracranial vessels

The etiology of concurrent stenoses of extracranial and intracranial vessels in patients with ischemic stroke is poorly understood, but hereditary factors are believed to be important. We aimed to determine whether genetic polymorphisms affecting homocysteine and lipid metabolism are associated with concurrent stenoses. The genotypes of 191 Han Chinese patients with acute ischemic stroke, of whom 47 (25%) had concurrent stenoses, and 167 healthy control patients in Hong Kong were examined for the following polymorphisms: paraoxonase 1 (PON1) Q192R, methylenetetrahydrofolate reductase (MTHFR) A222V, glutamate-cysteine ligase catalytic-subunit (GCLC)-129C>T, and oxidized low-density lipoprotein receptor (OLR) 3' untranslated region C>T (rs1050283). The genotype distributions of PON1 Q192R and MTHFR A222V, which affect lipid and homocysteine metabolism, differed significantly between patients with stroke and healthy controls. The presence of at least one R allele in PON1 Q192R and a TT allele in OLR rs1050283 were associated with concurrent stenoses. We also identified a possible association between the presence of at least one V allele in MTHFR A222V and concurrent stenoses. This study shows that genetic polymorphisms affecting homocysteine and lipid metabolism are possible risk factors for stroke and concurrent stenoses.

Pneumocystis pneumonia among HIV patients in Malaysia

Pneumocystis pneumonia (PCP) has become the most common opportunistic infection in HIV/AIDS patients with a CD4 count < or = 200. The incidence of PCP has declined as a result of prophylaxis and better highly active antiretroviral therapy (HAART). The objective of this study was to review the demographic data of HIV patients diagnosed clinically as having PCP at the Hospital Raja Perempuan Zainab II (HRPZ II) in Malaysia. This was a prospective study. All HIV patients admitted to HRPZ II with respiratory symptoms were enrolled in this study after giving informed consent. Their demographic data were collected. The total number of HIV patients reviewed in this study was 107. Nearly 60% of patients were clinically diagnosed as having pneumocystis pneumonia based on their signs, symptoms and chest x-ray findings. A CD4 count was available in 83 out of 107 patients. The fifty-three percent of patients(44) had a CD4 < 200 and were clinically diagnosed as having pneumocystis pneumonia. Thirty percent had a CD4 < 200 but did not have clinical pneumocystis pneumonia. Sixteen point nine percent had a CD4 > 200 and had clinical pneumocystis pneumonia, three of whom had received HAART, four patients had received prophylaxis. Overall, 94 patients (87.8%) received prophylaxis for pneumocystis pneumonia. Thirty-three patients (30.8%) received HAART. The occurrence of pneumocystis pneumonia was common before full implementation of HAART. Pneumocystis pneumonia can occur in patients with a CD4 >200.

BCR-ABL mutational studies for predicting the response of patients with chronic myeloid leukaemia to second-generation tyrosine kinase inhibitors after imatinib failure

Imatinib is the standard treatment for chronic myeloid leukaemia. BCR-ABL kinase domain mutation is the commonest mechanism implicated in imatinib resistance. In in-vitro studies, kinase domain mutations are variably resistant to second-line agents. We performed BCR-ABL kinase domain mutational studies in 25 patients in five institutions who failed imatinib and were treated with either nilotinib or dasatinib, to see if their mutational status would predict their clinical responses. Kinase domain mutations involving 11 amino acid substitutions were found in 12 (48%) patients. Most patients showed single kinase domain mutations. There was some concordance between reported drug sensitivity patterns and patient responses. Discordant responses could be related to drug dosage variations and unknown BCR-ABL independent mechanisms. The response prediction for patients with multiple kinase domain mutations was challenging and their mutational patterns could change after tyrosine kinase inhibitor therapy. Although BCR-ABL kinase domain mutational analysis has limitations as a means of predicting the clinical response to second-line tyrosine kinase inhibitors, it helps inform therapy decisions in the management of chronic myeloid leukaemia after imatinib failure.

Use of magnetic resonance angiography to predict long-term outcomes of ischemic stroke patients with concurrent stenoses in Hong Kong

PURPOSE

To determine the long-term outcome of ischemic stroke patients with concurrent intracranial and extracranial atherosclerosis using magnetic resonance angiography.

METHODS

A prospective cohort of patients in Hong Kong with acute ischemic stroke was studied with magnetic resonance angiography of the brain and carotid duplex. All patients were followed up regularly for the development of recurrent stroke, cardiac events, or death.

RESULTS

Totally 343 patients with acute ischemic stroke were included, of whom 104 (30%) had concurrent intracranial and extracranial lesions. The follow-up period was up to 76 months (mean 44.5 months). Overall, 55 patients (15.5%) died of any cause and 91 patients (26.5%) suffered a further nonfatal vascular event. The overall 5-year cumulative rates of mortality, restroke and poor outcomes (combined death and further vascular events) were 18, 27 and 37%, respectively. In patients with concurrent lesions, these rates were 31, 41 and 51%, respectively. The corresponding rates were 13, 22 and 31% in patients without concurrent lesions. The risks were highest in the first year after stroke. More deaths (log rank, 16.3; p = 0.0001), restrokes (log rank, 9.71; p = 0.002) and poor outcomes (log rank, 13.87; p = 0.0001) were found among patients with concurrent lesions. The presence of concurrent vascular lesions, advanced age, smoking, hyperlipidemia and previous history of stroke were independent predictors of poor outcomes.

CONCLUSIONS

The long-term prognosis of ischemic stroke patients with concurrent atherosclerosis of intracranial and extracranial vessels is poor. They are at high risk of further vascular events or death.

FGFR3 promotes synchondrosis closure and fusion of ossification centers through the MAPK pathway

Activating mutations in FGFR3 cause achondroplasia and thanatophoric dysplasia, the most common human skeletal dysplasias. In these disorders, spinal canal and foramen magnum stenosis can cause serious neurologic complications. Here, we provide evidence that FGFR3 and MAPK signaling in chondrocytes promote synchondrosis closure and fusion of ossification centers. We observed premature synchondrosis closure in the spine and cranial base in human cases of homozygous achondroplasia and thanatophoric dysplasia as well as in mouse models of achondroplasia. In both species, premature synchondrosis closure was associated with increased bone formation. Chondrocyte-specific activation of Fgfr3 in mice induced premature synchondrosis closure and enhanced osteoblast differentiation around synchondroses. FGF signaling in chondrocytes increases Bmp ligand mRNA expression and decreases Bmp antagonist mRNA expression in a MAPK-dependent manner, suggesting a role for Bmp signaling in the increased bone formation. The enhanced bone formation would accelerate the fusion of ossification centers and limit the endochondral bone growth. Spinal canal and foramen magnum stenosis in heterozygous achondroplasia patients, therefore, may occur through premature synchondrosis closure. If this is the case, then any growth-promoting treatment for these complications of achondroplasia must precede the timing of the synchondrosis closure.

Detection of Cryptosporidium parvum in HIV-infected patients in Malaysia using a molecular approach

This cross-sectional study determined the prevalence of cryptosporidiosis in HIV-infected patients using polymerase chain reaction (PCR). Stool specimens were collected from HIV infected patients who were admitted to Hospital Raja Perempuan Zainab II, Kota Bharu, Malaysia, for various indications from December 2004 to December 2005. A modified acid-fast stain was performed on the direct stool smears, then the stool specimens were further tested using nested PCR targeting the 18S rRNA gene of Cryptosporidium parvum, with a built-in internal control (IC). Out of 59 samples, 11 were positives. Nested PCR identified a total of nine samples (16%) compared to microscopy, which identified only three samples. All PCR negative results showed IC amplicons, suggesting that these samples were true negatives and were not due to inhibition of PCR. This study highlights the importance of molecular diagnosis in determining the true prevalence and epidemiology of C. parvum.

BpeAB-OprB, a multidrug efflux pump in Burkholderia pseudomallei

Burkholderia pseudomallei, the causative agent of melioidosis, is intrinsically resistant to a wide range of antimicrobial agents, including beta-lactams, aminoglycosides, macrolides, and polymyxins. An operon, bpeR-bpeA-bpeB-oprB, which encodes a putative repressor, a membrane fusion protein, an inner membrane protein, and an outer membrane protein, respectively, of a multidrug efflux pump of the resistance-nodulation-division family was identified in B. pseudomallei. The divergently transcribed bpeR gene encodes a putative repressor protein of the TetR family which probably regulates the expression of the bpeAB-oprB gene cluster. Comparison of the MICs and minimal bactericidal concentrations of antimicrobials for bpeAB deletion mutant KHW Delta bpeAB and its isogenic wild-type parent, KHW, showed that the B. pseudomallei BpeAB-OprB pump is responsible for the efflux of the aminoglycosides gentamicin and streptomycin, the macrolide erythromycin, and the dye acriflavine. Antibiotic efflux by the BpeAB-OprB pump was dependent on a proton gradient and differs from that by the AmrAB-OprA pump in that it did not efflux the aminoglycoside spectinomycin or the macrolide clarithromycin. The broad-spectrum efflux pump inhibitor MC-207,110 did not potentiate the effectiveness of the antimicrobials erythromycin and streptomycin in B. pseudomallei.

Flagella are virulence determinants of Burkholderia pseudomallei

Burkholderia pseudomallei, a facultatively intracellular pathogen, is a flagellated and motile gram-negative bacterium and is the causative agent of melioidosis in humans. Flagella are commonly recognized as important virulence determinants expressed by bacterial pathogens since the motility phenotype imparted by these organelles often correlates with the ability of an organism to cause disease. We used a virulent isolate of B. pseudomallei, KHW, to construct an isogenic deletion mutant with a mutation in the flagellin gene (fliC) by gene replacement transposon mutagenesis. The KHWDeltafliCKm mutant was aflagellate and nonmotile in semisolid agar. The isogenic KHWDeltafliCKm mutant was not impaired in terms of the ability to invade and replicate in cultured human lung cells compared with the wild type. It was also equally virulent in slow-killing assays involving Caenorhabditis elegans, but it was avirulent during intranasal infection of BALB/c mice. Very few bacteria, if any, were isolated from the lungs and spleens of KHWDeltafliCKm-infected mice. In contrast, the bacterial loads in the lungs and spleens were similar in mice infected with KHW and in mice infected with the complemented mutant, KHWDeltafliCKm/pUCP28TfliC. Unlike the Syrian hamster or diabetic rat models of infection, the B. pseudomallei flagellin was also a virulence factor during intraperitoneal infection of BALB/c mice. In this study, all animals infected with KHWDeltafliCKm remained healthy and did not succumb to disease regardless of the route of infection. The flagellum is therefore an important and necessary virulence determinant of B. pseudomallei during intranasal and intraperitoneal infection of mice.

Clinical management of childhood osteoporosis

A current working definition of osteoporosis in children is 'fragility fractures in association with low bone mass'. This review illustrates the determinants of bone mass and fracture risk. We elucidate the pathophysiology and causes of osteoporosis in various childhood disorders, with a particular focus on the commonest iatrogenic problem, glucocorticoid-induced osteoporosis. We discuss clinical evaluation, investigation and multidisciplinary management including lifestyle advice, diet, physiotherapy and occupational therapy, drug treatments and monitoring for children with osteoporosis. We also emphasise the important concepts of bone mass assessment and interpretation in children.

Constituents of the roots and stems of Aristolochia mollissima

Five new sesquiterpenes, mandolins R (1), S (2), U (3), W (4), and X (5), together with 39 known compounds, were isolated from the dried roots and stems of Aristolochia mollissima. Their structures were determined by spectroscopic methods.

Constituents from the stem and root of Aristolochia kaempferi

Three new phenanthrene derivatives, aristoliukine-C, aristofolin-E and aristolochic acid-Ia methyl ester, and one new sesquiterpene, madolin-P, together with 58 known compounds were isolated from the stem and root of Aristolochia kaempferi. The structures of these compounds were determined by spectral analysis. The cytotoxicity and antiplatelet activity of the isolated compounds are also discussed.

The constituents of the root and stem of Aristolochia cucurbitifolia Hayata and their biological activity

Four new compounds, three phenanthrene derivatives, aristolochic acid-III methyl ester (1), cepharanone C (2), and sodium 7-hydroxyl-8-methoxyaristolate (3), and the benzoate derivative, sodium 3,4-dimethoxybenzoate (4), together with 53 known compounds were isolated and characterized from the fresh root and stem of Aristolochia cucurbitifolia. Their structures were elucidated by spectral analyses and chemical transformations. The cytotoxicity and antiplatelet activity of the isolated compounds are also discussed.

The constituents of the root and stem of Aristolochia heterophylla Hemsl

Seven new compounds, sodium aristolochate-VII (1), aristolactam-CIV (2), madolin-I (3), -J (4), -K (5), -L (6) and -M (7) together with 71 known compounds were isolated and characterized from the fresh root and stem of Aristolochia heterophylla Hemsl. Their structures were determined by spectral methods. Compound 8 was revised as aromadendrane-4beta, 10beta-diol by spectral data and single-crystal X-ray analysis.

Interface for capillary electrophoresis coupled with inductively coupled plasma atomic emission spectrometry

A modified concentric nebulizer was used as the interface to couple capillary electrophoresis (CE) to inductively coupled plasma atomic emission spectrometry (ICP-AES). The CE capillary replaces the central tube of the concentric nebulizer. The tip of the nebulizer tapers slowly to allow uncertainty in the position of the capillary. A platinum wire was inserted into the CE capillary to provide electrical connection to the CE power supply. pH changes inside the capillary due to electrolysis of the background buffer electrolyte was small and has minimal effects on the CE separation. The peak broadening effects due to the nebulizing gas flow, however, were significant. Resolution decreases quickly when the flow-rate of the carrier gas increases. Sample stacking technique was used to improve the resolution of species of opposite charge, e.g., Cr(VI) vs. Cr(III) ions. Detection limit of Cr based on peak area is approximately 10 ppb for the CE-ICP-AES system.

Sesquiterpene esters of aristolochic acid from the root and stem of Aristolochia heterophylla

Three novel sesquiterpene esters of aristolochic acid, aristoloterpenate-II (2), -III (3), and-IV (4), together with known aristoloterpenate-I (1), were isolated and characterized from the root and stem of Aristolochia heterophylla. Their structures were elucidated by spectroscopic methods. The absolute configuration of these compounds at C-4' was determined as R by circular dichroic studies. These compounds showed cytotoxicity against hepatoma G2, 2, 2, 15 cells.

Four aristolochic acid esters of rearranged ent-elemane sesquiterpenes from aristolochia heterophylla

Four aristolochic acid esters of ent-elemane type sesquiterpene having a new carbon skeleton, aristophyllides A (1), B (2), C (3), and D (4), were isolated from the stems and roots of Aristolochia heterophylla. The esters were characterized by NMR and MS methods and included is a study of absolute configurations using the CD exciton chirality method.

Naphthoquinone esters from the root of Rhinacanthus nasutus

Reinvestigation of the root of Rhinacanthus nasutus afforded, in addition to rhinacanthin-A to -D reported previously, two new dimethyldihydropyranonaphthoquinone esters (5, 6) and eight new 2-hydroxy-1,4-naphthoquinone esters (7-14) were isolated. The stereochemistry of rhinacanthin-A was determined as the R configuration. Compounds rhinacanthin-G to -N, belong to a class of 2-hydroxy-3-(3-hydroxy-2,2-dimethylpropyl)-1,4-naphthoquinone esters, and so far have been isolated only in this plant. Their biosynthesis is also discussed.

Prevalence and genotypes of alpha- and beta-thalassemia carriers in Hong Kong -- implications for population screening

BACKGROUND

The thalassemias are common in southern China. We determined the prevalence of heterozygous carriers of these genetic disorders in Hong Kong and assessed the feasibility of a community-based screening program.

METHODS

An educational and screening program for the thalassemias was carried out in three high schools with a total of 2420 students. Seventy-five percent of the students agreed to undergo screening, which consisted of blood counts, hemoglobin electrophoresis, serum ferritin measurements, and DNA analyses.

RESULTS

Of the 1800 blood samples tested, 150 (8.3 percent) had microcytosis (mean corpuscular volume, <80 microm3). Ninety students (5.0 percent) were carriers of alpha-thalassemia, of whom 81 (4.5 percent) were carriers of the Southeast Asian type of deletion, in which both alpha-globin genes on the same chromosome 16 are deleted. Sixty-one students (3.4 percent) were carriers of either beta-thalassemia or the mutation coding for hemoglobin E. Six students were carriers of both alpha- and beta-thalassemias. On the basis of these figures, the estimated numbers of pregnancies in Hong Kong in which the fetus is at risk for homozygous alpha-thalassemia and beta-thalassemia major or intermedia are 145 and 80 per year, respectively. In Hong Kong the actual numbers of women referred for prenatal diagnoses of these disorders are approximately 95 and 40 per year, respectively.

CONCLUSIONS

Despite the availability of hospital-based screening and prenatal diagnosis for many years in Hong Kong, many women carrying fetuses at risk for thalassemia are not referred for genetic counseling. A community-based program of education, screening, and counseling is needed in Hong Kong and southern China.

The role of galanin and its receptor in the feedback regulation of growth hormone secretion

GH controls its own secretion through a mechanism involving short-loop feedback regulation of the synthesis and release of GH-releasing hormone (GHRH). GHRH neurons coexpress the peptide galanin, but the functional significance of this coexpression is unknown. In this study, we tested the hypotheses that 1) galanin gene expression in GHRH neurons is regulated by GH and 2) somatostatin (SS) or GHRH neurons are a target for the action of galanin in the hypothalamus. First, we compared levels of galanin messenger RNA (mRNA) in GHRH neurons between normal male rats and Lewis dwarf rats, which have markedly reduced blood levels of GH. The brains of normal and dwarf animals were processed for detection of galanin mRNA and GHRH mRNA by double-label in situ hybridization. We observed that Lewis dwarf rats had significantly reduced levels of galanin mRNA in their GHRH neurons (P < 0.05). Next, we tested the hypothesis that GH regulates galanin gene expression in GHRH neurons by experimentally altering circulating levels of GH. Three groups of adult male rats were used: 1) intact rats (n = 7); 2) hypophysectomized (hypox) rats (n = 7); and 3) hypox rats treated with 1.5 mg of rat GH (rGH) over a 3-day period (n = 6). At the end of the treatment period, the animals were killed, and their brains were collected and processed for double-label in situ hybridization for GHRH mRNA and galanin mRNA. The signal level of galanin mRNA in GHRH neurons was reduced in hypox animals to less than 10% of that in intact controls (P < 0.0001); whereas, the levels of galanin mRNA signal in GHRH neurons did not differ significantly between the groups of intact and rGH-treated hypox rats. Finally, to determine whether SS or GHRH neurons are targets for galanin, we used double-label in situ hybridization to determine whether either of these populations of neurons express galanin receptor mRNA. A subset of SS neurons in the PeN appeared to express the galanin receptor mRNA, whereas few, if any, GHRH neurons appeared to do so. We conclude that galanin, like its cotransmitter GHRH, is a target for GH action, and we infer that galanin may play a role in the feedback control of GH secretion by exerting a direct effect on SS neurons.

Retroviral transduction of hematopoietic progenitor cells with mutant p53 promotes survival and proliferation, modifies differentiation potential and inhibits apoptosis

Mutations in the p53 tumor suppressor gene have been shown to be associated with many human tumors and various leukemias and lymphomas. To examine whether constitutive overexpression of mutant p53 can effect transformation of normal hematopoietic cells, a mutant p53 gene was introduced into normal murine bone marrow hematopoietic cells by retroviral gene transfer. Compared to vector alone-infected cells, hematopoietic progenitor cells transduced with mutant p53 showed increased proliferative potential, enhanced cloning efficiencies and a modified differentiation pattern in vitro. In addition, mutant p53-transduced hematopoietic cells were more resistant to loss of viability and/or induction of apoptosis when cultured in a low concentration of serum or in the absence of both growth factors and serum. These effects occurred rapidly with no apparent contributory secondary events. No permanent cell lines or growth factor-independent cell strains were obtained. The results indicate that introduction of mutant p53 into normal hematopoietic cells in vitro contributes to transformation, including enhanced proliferative potential, modified differentiation and the suppression of apoptosis in these cells.

A comparison of Sil-K and Epiderm in scar management

Twenty-six patients with a total of 45 scars were studied to determine the efficacy of the new silicone sheet, Sil-K, in treating hypertrophic scars. Twenty-eight scars were treated with Sil-K and 17 scars were treated with the conventional gel, Epiderm. Evaluation based on the scar's colour, texture, thickness and regularity was done on a monthly interval for 6 months. Preliminary results suggest that both Sil-K and Epiderm are effective in treating hypertrophic scars. All of the four parameters studied showed improvement, with colour, texture and regularity showing higher percentage of improvement than thickness (90, 90, 80 and 50 per cent respectively). Complications such as rashes, pruitus, maceration and dry skin were reported by some subjects. Epiderm and Sil-K were also compared across factors such as cost, durability, conformity and hygiene to assist therapists in choosing the suitable silicone sheet for each individual patient.

Regulation of hypothalamic neuropeptide-Y neurons by growth hormone in the rat

GH is thought to exert a short-loop feedback action on the hypothalamic somatostatin- and GH-releasing hormone (GHRH)-containing neurons. The direct actions of GH are mediated through GH receptors. In the male rat, few GHRH-containing neurons in the arcuate nucleus (ARC) appear to express the GH receptor messenger RNA (mRNA); however, some unidentified neurons near GHRH neurons do. Recent evidence suggests that neuropeptide-Y (NPY)-containing neurons, which are located near GHRH neurons in the ARC, are targets for GH action because treatment of rats with GH induces c-fos expression in these cells. We conducted two experiments to test the hypothesis that GH acts on NPY neurons in the ARC. First, we performed double-label in situ hybridization to determine whether NPY neurons in the ARC express GH receptor mRNA. Second, we investigated the possibility that GH regulates NPY mRNA expression by using in situ hybridization to compare ARC NPY mRNA levels among groups of normal (n = 7), hypophysectomized (n = 7), and hypophysectomized/rGH-treated (1.5 mg rat GH over 3 days; n = 6) rats. We found that most of the NPY-containing neurons in the ARC expressed GH receptor mRNA, whereas hypothalamic NPY neurons residing outside of the ARC did not. Furthermore, hypophysectomy significantly decreased NPY mRNA levels, and GH treatment restored the levels to those of the intact animals. We conclude that GH regulates the activity of NPY neurons in the ARC by a direct action on GH receptors that are expressed by NPY neurons. Whether the action of GH on NPY neurons in the ARC is related to the feedback control of GH secretion or some other physiological function remains to be determined.

Role of NPY neurones in GH-dependent feedback signalling to the brain

The neuroendocrine regulation of pulsatile growth hormone (GH) secretion involves the reciprocal interactions between growth hormone-releasing hormone (GHRH)- and somatostatin-containing neurones, residing primarily in the hypothalamic arcuate nucleus (ARC) and the periventricular nucleus (PeN), respectively. Considerable evidence supports the concept that GH itself participates in the regulation of its own rhythmic secretion through a reciprocal feedback on GHRH and somatostatin neurones. The direct actions of GH are mediated through GH receptors, and in the PeN, the majority of somatostatin neurones express this receptor. GH induces the expression of the immediate early gene c-fos in the ARC; however, few GHRH residing in the ARC express the GH receptor, suggesting that the action of GH on GHRH cells must be indirect through another population of unidentified cells. NPY neurones express c-fos in response to GH, and preliminary results suggest that NPY neurones in the ARC express the GH receptor. These observations suggest that NPY neurones play a physiological role in the feedback of regulation of GH secretion.

Variations in problem conceptualizations and intended solutions among Hong Kong students

Cognitive schema were used to explain health and illness behaviors among Chinese students. University students in Hong Kong were asked to attribute causes and suggest solutions to five health/mental health problems: Weakness/Fatigue, Tension/Anxiety, Sleep Difficulty, Hollow/Emptiness, and Headache. The patterns of endorsement on the causal and solution categories used for the five problems were compared using a new asymptotic chi-squared test. The response patterns were found to be significantly different across the five problems. Each problem was attributed to multiple causes including psychological, social, situational, somatic, and existential factors. The intended solutions were often related to the nature of the causal attributions especially when the problems were mild. In lay help-seeking, the Hong Kong students would attempt a variety of self-help measures. However, for professional consultation, the medical doctor would be the primary care professional the students would turn to for most of the problems except in the case of Hollow/Emptiness.

Recovery from T cell depletion during murine listeriosis and effect on a T-dependent antibody response

During the infection of mice with Listeria monocytogenes, there is a profound depletion of T (Thy-1+ Ig-) lymphocytes between days 1 and 4, followed by an increase in T cells to three times normal levels by day 9. The recovery of T cell numbers required cell proliferation, being sensitive to vinblastin and cyclophosphamide. Adult thymectomy 6 months before infection had no effect on recovery. The repopulating cells were no more sensitive than normal T cells to hydrocortisone. B lymphocytes (Ig+ cells) and null (Thy-1-Ig-) cells increased from day 1 after the injection of either live or (in contrast to T cells) killed Listeria organisms. Their increase was inhibited by vinblastin and cyclophosphamide. Despite T cell depletion, no depression of the antibody response to the T-dependent antigen, sheep erythrocytes, occurred during infection or when spleen cells were adoptively transferred from infected mice to irradiated recipients.

Mechanism of depletion of T lymphocytes from the spleen of mice infected with Listeria monocytogenes

Marked changes in the splenic lymphocyte populations during murine infection with Listeria monocytogenes were observed histologically and quantitated by the immunofluorescence of Thy-1+ immunoglobulin (Ig-) (T) and Ig+ (B) cells. Cells were depleted from the T-dependent areas of the spleen, and the number of T cells in suspensions prepared from spleens of mice 1 to 3 days after primary or secondary infection were less than 1/10 of normal. High numbers of alcohol-killed Listeria sp. did not cause any depletion. Depletion was not prevented by adrenalectomy. Although injected radiolabeled T cells distributed normally between spleen, liver, lymph node, and gut in infected mice, there appeared to be a barrier to their entry into depleted T-dependent areas of the spleen. Evidence for the destruction of T cells, but not of B cells, in the infected mouse spleen was obtained.