Early life programming and the risk of non-alcoholic fatty liver disease.

Non-alcoholic fatty liver disease (NAFLD) is associated with obesity, insulin resistance, type 2 diabetes and cardiovascular disease and can be considered the hepatic manifestation of the metabolic syndrome. NAFLD represents a spectrum of disease, from the relatively benign simple steatosis to the more serious non-alcoholic steatohepatitis, which can progress to liver cirrhosis, hepatocellular carcinoma and end-stage liver failure, necessitating liver transplantation. Although the increasing prevalence of NAFLD in developed countries has substantial implications for public health, many of the precise mechanisms accounting for the development and progression of NAFLD are unclear. The environment in early life is an important determinant of cardiovascular disease risk in later life and studies suggest this also extends to NAFLD. Here we review data from animal models and human studies which suggest that fetal and early life exposure to maternal under- and overnutrition, excess glucocorticoids and environmental pollutants may confer an increased susceptibility to NAFLD development and progression in offspring and that such effects may be sex-specific. We also consider studies aimed at identifying potential dietary and pharmacological interventions aimed at reducing this risk. We suggest that further human epidemiological studies are needed to ensure that data from animal models are relevant to human health.

The role of microaerophilic Fe-oxidizing micro-organisms in producing banded iron formations.

Despite the historical and economic significance of banded iron formations (BIFs), we have yet to resolve the formation mechanisms. On modern Earth, neutrophilic microaerophilic Fe-oxidizing micro-organisms (FeOM) produce copious amounts of Fe oxyhydroxides, leading us to wonder whether similar organisms played a role in producing BIFs. To evaluate this, we review the current knowledge of modern microaerophilic FeOM in the context of BIF paleoenvironmental studies. In modern environments wherever Fe(II) and O2 co-exist, microaerophilic FeOM proliferate. These organisms grow in a variety of environments, including the marine water column redoxcline, which is where BIF precursor minerals likely formed. FeOM can grow across a range of O2 concentrations, measured as low as 2 µm to date, although lower concentrations have not been tested. While some extant FeOM can tolerate high O2 concentrations, many FeOM appear to prefer and thrive at low O2 concentrations (~3-25 µm). These are similar to the estimated dissolved O2 concentrations in the few hundred million years prior to the 'Great Oxidation Event' (GOE). We compare biotic and abiotic Fe oxidation kinetics in the presence of varying levels of O2 and show that microaerophilic FeOM contribute substantially to Fe oxidation, at rates fast enough to account for BIF deposition. Based on this synthesis, we propose that microaerophilic FeOM were capable of playing a significant role in depositing the largest, most well-known BIFs associated with the GOE, as well as afterward when global O2 levels increased.

Planktonic marine iron oxidizers drive iron mineralization under low-oxygen conditions.

Observations of modern microbes have led to several hypotheses on how microbes precipitated the extensive iron formations in the geologic record, but we have yet to resolve the exact microbial contributions. An initial hypothesis was that cyanobacteria produced oxygen which oxidized iron abiotically; however, in modern environments such as microbial mats, where Fe(II) and O2 coexist, we commonly find microaerophilic chemolithotrophic iron-oxidizing bacteria producing Fe(III) oxyhydroxides. This suggests that such iron oxidizers could have inhabited niches in ancient coastal oceans where Fe(II) and O2 coexisted, and therefore contributed to banded iron formations (BIFs) and other ferruginous deposits. However, there is currently little evidence for planktonic marine iron oxidizers in modern analogs. Here, we demonstrate successful cultivation of planktonic microaerophilic iron-oxidizing Zetaproteobacteria from the Chesapeake Bay during seasonal stratification. Iron oxidizers were associated with low oxygen concentrations and active iron redox cycling in the oxic-anoxic transition zone (<3 µm O2 , <0.2 µm H2 S). While cyanobacteria were also detected in this transition zone, oxygen concentrations were too low to support significant rates of abiotic iron oxidation. Cyanobacteria may be providing oxygen for microaerophilic iron oxidation through a symbiotic relationship; at high Fe(II) levels, cyanobacteria would gain protection against Fe(II) toxicity. A Zetaproteobacteria isolate from this site oxidized iron at rates sufficient to account for deposition of geologic iron formations. In sum, our results suggest that once oxygenic photosynthesis evolved, microaerophilic chemolithotrophic iron oxidizers were likely important drivers of iron mineralization in ancient oceans.

Measuring Activity Performance of Continuing Care Residents Using the activPAL: An Exploratory Study.

Few studies have measured the activity patterns of continuing care residents using objective, uniaxial, accelerometers such as the activPAL. This exploratory study described the activity performance of continuing care residents and explored the correlation of activity performance with grip strength, falls and mobility. Data were gathered from 24 continuing care residents. Participants (82.3 ± 5.8 years of age), wore the activPAL an average of 12.60 hours per day (SD = 0.96) and were stepping for a median of 0.47 hours (25th and 75th percentiles = 0.31, 0.81) with a median step count of 1906 steps (25th and 75th percentiles = 1216, 3420). Participants were inactive (sitting/lying/standing) for a mean 11.99 hours (SD = 1.03). No statistically significant correlations were identified between activity performance (active time, inactive time or step count) and grip strength, falls or mobility. Ambulatory older adults in continuing care centres were more sedentary compared to community-dwelling older adults or older adults with cancer.

Involvement of tumor suppressors PTEN and p53 in the formation of multiple subtypes of liposarcoma.

Liposarcoma (LPS) is a type of soft tissue sarcoma that mostly occurs in adults, and in humans is characterized by amplifications of MDM2 and CDK4. The molecular pathogenesis of this malignancy is still poorly understood and, therefore, we developed a mouse model with conditional inactivation of PTEN and p53 to investigate these pathways in the progression of the disease. We show that deletion of these two tumor suppressors cooperate in the formation of multiple subtypes of LPS (from well-differentiated LPS to pleomorphic LPS). In addition, progression of the tumors is further characterized by the expression of D cyclins and CDK4/6, which allow for continued cell division. Microarray analysis also revealed novel genes that are differentially expressed between different subtypes of LPS, which could aid in understanding the disease and to unravel potential new therapeutic targets.

The bromodomain and extra-terminal inhibitor CPI203 enhances the antiproliferative effects of rapamycin on human neuroendocrine tumors.

Endogenous c-MYC (MYC) has been reported to be a potential pharmacological target to trigger ubiquitous tumor regression of pancreatic neuroendocrine tumors (PanNETs) and lung tumors. Recently inhibitors of bromodomain and extra-terminal (BET) family proteins have shown antitumor effects through the suppression of MYC in leukemia and lymphoma. In this paper, we investigated the antitumor activity of a BET protein bromodomain inhibitor (BETi) CPI203 as a single agent and in combination with rapamycin in human PanNETs. We found that exposure of human PanNET cell lines to CPI203 led to downregulation of MYC expression, G1 cell cycle arrest and nearly complete inhibition of cell proliferation. In addition, overexpression of MYC suppressed the growth inhibition caused by CPI203 and knockdown of MYC phenocopied the effects of CPI203 treatment. These findings indicate that suppression of MYC contributed to the antiproliferative effects of BETi inhibition in human PanNET cells. Importantly, CPI203 treatment enhanced the antitumor effects of rapamycin in PanNET cells grown in monolayer and in three-dimensional cell cultures, as well as in a human PanNET xenograft model in vivo. Furthermore, the combination treatment attenuated rapamycin-induced AKT activation, a major limitation of rapamycin therapy. Collectively, our data suggest that targeting MYC with a BETi may increase the therapeutic benefits of rapalogs in human PanNET patients. This provides a novel clinical strategy for PanNETs, and possibly for other tumors as well.

Morphology of biogenic iron oxides records microbial physiology and environmental conditions: toward interpreting iron microfossils.

Despite the abundance of Fe and its significance in Earth history, there are no established robust biosignatures for Fe(II)-oxidizing micro-organisms. This limits our ability to piece together the history of Fe biogeochemical cycling and, in particular, to determine whether Fe(II)-oxidizers played a role in depositing ancient iron formations. A promising candidate for Fe(II)-oxidizer biosignatures is the distinctive morphology and texture of extracellular Fe(III)-oxyhydroxide stalks produced by mat-forming microaerophilic Fe(II)-oxidizing micro-organisms. To establish the stalk morphology as a biosignature, morphologic parameters must be quantified and linked to the microaerophilic Fe(II)-oxidizing metabolism and environmental conditions. Toward this end, we studied an extant model organism, the marine stalk-forming Fe(II)-oxidizing bacterium, Mariprofundus ferrooxydans PV-1. We grew cultures in flat glass microslide chambers, with FeS substrate, creating opposing oxygen/Fe(II) concentration gradients. We used solid-state voltammetric microelectrodes to measure chemical gradients in situ while using light microscopy to image microbial growth, motility, and mineral formation. In low-oxygen (2.7-28 µm) zones of redox gradients, the bacteria converge into a narrow (100 µm-1 mm) growth band. As cells oxidize Fe(II), they deposit Fe(III)-oxyhydroxide stalks in this band; the stalks orient directionally, elongating toward higher oxygen concentrations. M. ferrooxydans stalks display a narrow range of widths and uniquely biogenic branching patterns, which result from cell division. Together with filament composition, these features (width, branching, and directional orientation) form a physical record unique to microaerophilic Fe(II)-oxidizer physiology; therefore, stalk morphology is a biosignature, as well as an indicator of local oxygen concentration at the time of formation. Observations of filamentous Fe(III)-oxyhydroxide microfossils from a ~170 Ma marine Fe-Si hydrothermal deposit show that these morphological characteristics can be preserved in the microfossil record. This study demonstrates the potential of morphological biosignatures to reveal microbiology and environmental chemistry associated with geologic iron formation depositional processes.

Major haemoptysis in Hong Kong: aetiologies, angiographic findings and outcomes of bronchial artery embolisation.

SETTING: Tertiary referral centres. OBJECTIVE: To provide comprehensive updates on the aetiologies, angiographic findings and outcomes of bronchial artery embolisation (BAE) for life-threatening haemoptysis in Hong Kong. DESIGN: Retrospective review of clinical records of consecutive patients presenting with life-threatening haemoptysis from 2000 to 2006. RESULTS: There were 3006 admissions due to haemoptysis involving 2260 patients during the study period; of these, 251 patients had life-threatening haemoptysis. Pulmonary tuberculosis (PTB) (active or inactive) and bronchiectasis were the main underlying causes. BAE was attempted in 167 patients. There was a high prevalence of bilateral bronchial arterial abnormalities (31.7%), presence of abnormal non-bronchial arteries (41.3%) and presence of broncho-pulmonary shunt (38.9%). BAE had a high immediate success rate of 95.7%, with a 5-year recurrence rate of 45.0%. Recurrent life-threatening haemoptysis was independently associated with past history of haemoptysis (P = 0.024), presence of broncho-pulmonary shunt (P = 0.013), and incomplete embolisation (P = 0.002). Complications were uncommon (<5%) and self-limiting. CONCLUSIONS: In Hong Kong, about one tenth of admissions due to haemoptysis were life-threatening. PTB and bronchiectasis were the major causes. Complications due to BAE were uncommon and self-limiting, with super-selective catheters.

Molecular and genetic characterisation of the SARS coronavirus auxiliary protein X1 in Drosophila.

1. We have generated monoclonal antibodies against the SARS coronavirus (SARS-CoV) X1/3a protein (3a), which are suitable for western blotting, immunocytochemistry, and immunohistochemistry. 2. We have established and characterised an in-vivo 3a transgenic Drosophila model, and demonstrated its usefulness in studying SARS-CoV 3a gene function. 3. We validated our in-vivo findings on 3a gene function in mammalian Vero E6 cells. 4. Our findings raise the possibility of using ion channel blockers as a novel approach to suppress SARS-CoV-induced cell death.

Cadaver validation of intensity-based ultrasound to CT registration.

A method is presented for the rigid registration of tracked B-mode ultrasound images to a CT volume of a femur and pelvis. This registration can allow tracked surgical instruments to be aligned with the CT image or an associated preoperative plan. Our method is fully automatic and requires no manual segmentation of either the ultrasound images or the CT volume. The parameter which is directly related to the speed of sound through tissue has also been included in the registration optimisation process. Experiments have been carried out on six cadaveric femurs and three cadaveric pelves. Registration results were compared with a "gold standard" registration acquired using bone implanted fiducial markers. Results show the registration method to be accurate, on average, to 1.6 mm root-mean-square target registration error.

In vivo functional characterization of the SARS-Coronavirus 3a protein in Drosophila.

The Severe Acute Respiratory Syndrome-Coronavirus (SARS-CoV) 3a locus encodes a 274 a.a. novel protein, and its expression has been confirmed in SARS patients. To study functional roles of 3a, we established a transgenic fly model for the SARS-CoV 3a gene. Misexpression of 3a in Drosophila caused a dominant rough eye phenotype. Using a specific monoclonal antibody, we demonstrated that the 3a protein displayed a punctate cytoplasmic localization in Drosophila as in SARS-CoV-infected cells. We provide genetic evidence to support that 3a is functionally related to clathrin-mediated endocytosis. We further found that 3a misexpression induces apoptosis, which could be modulated by cellular cytochrome c levels and caspase activity. From a forward genetic screen, 78 dominant 3a modifying loci were recovered and the identity of these modifiers revealed that the severity of the 3a-induced rough eye phenotype depends on multiple cellular processes including gene transcriptional regulation.

Protein profiling of cervical cancer by protein-biochips: proteomic scoring to discriminate cervical cancer from normal cervix.

Analysis of multiple proteins is thought to be essential for establishment of signature proteomic patterns that may distinguish cancer from non-cancer. Surface-enhanced laser desorption/ionization (SELDI) is an affinity-based mass spectrometric method in which proteins of interest are selectively absorbed to a chemically modified surface on a biochip. This technology may provide protein profiling of a variety of biological specimens. In this study, we explored whether the protein biochip SELDI approach could differentiate cervical cancer from non-cancer cohorts. We screened protein profiles generated by SELDI in 62 cervical epithelial cell samples microdissected from 35 invasive cervical cancer and 27 age-matched normal cervix tissue specimens, respectively. The cell lysates of pure populations of cervical cells were applied onto Ciphergen ProteinChip WCX2 Arrays. Proteins bound to the chips were analyzed on a ProteinChip Reader Model PBS II. Derived proteomic patterns were converted to a simple proteomic scoring for distinguishing cancer from non-cancer cohorts. SELDI protein profiles of cell lysates from 20 cervical cancer and 15 normal cervix tissue specimens were used to train and develop a classification scoring system that used a seven-protein mass pattern. The training samples could be correctly discriminated. When a test set of 27 samples was used for evaluation of this scoring system to distinguish cervical cancer from non-cancer, a sensitivity of 87%, a specificity of 100%, a positive predictive value of 100%, and a negative predictive value of 86% for the test population were obtained. All seven proteins appeared to be down regulated in cervical cancer. The results from this study indicate that the proteomics approach of SELDI mass spectrometry, in combination with a simple scoring system, may distinguish cervical cancer from its normal counterpart. If this approach is also workable in the analysis of cervical exfoliated cell lysate, it might potentially be used in the early diagnosis of invasive cervical cancer. In addition, the identification of these specific proteins in cervical cancer may also facilitate the discovery of new cervical tumor marker(s).

Primary care physicians in public and private sectors perceive different learning needs.

We compared the perceived learning needs of primary care physicians from the public and private sectors who responded to a questionnaire before taking educational courses in Family Medicine. They rated their perceived learning needs on 71 items of clinical practices and practice management on a scale of 1-10. The ratings of their learning needs were closely related to the perceived needs of their daily work. The private physicians gave higher ratings to most items. Both groups of physicians shared similar least-preferred items (e.g. suturing, plastering, taking Pap smears) but had very different most-preferred ones. Public physicians wished to improve their care of individual patients (e.g. skin, eye, ear-nose-throat problems). Private physicians were more concerned with professional development to improve their practice (e.g. audits, counselling, adult learning). Organizers of educational programmes should assess and discuss with physicians their expected learning needs at the planning stage of a programme.

Opinion survey of Hong Kong private primary care doctors about cervical screening.

The policy and practice of Hong Kong private primary care doctors regarding cervical screening were investigated by way of two different questionnaires sent to comparable random survey samples. The overall response rate was 60.8% (313/515). Both sexes of eligible doctors believed that cervical smears were effective and important, but only 40.2% (47/117) of male doctors performed the test compared with 65.5% (19/29) of female doctors. Those doctors who do not perform the test themselves usually refer their patients elsewhere. The small proportion of private doctors offering cervical smears may reduce opportunities for women who need them. Over 80% of private doctors recommended annual smears despite local recommendations for 3-yearly tests, while graduates from western countries were more likely to recommend longer intervals. Since the proportion of women in Hong Kong having Papanicolaou tests is still low, effort should focus on providing smears for more women, rather than repeated annual testing of those who already participate.

Promoter analysis of the nuclear gene encoding the chloroplast glyceraldehyde-3-phosphate dehydrogenase B subunit of Arabidopsis thaliana.

The promoter of the nuclear gene, GAPB, which encodes the B subunit of chloroplast glyceraldehyde-3-phosphate dehydrogenase (GADPH) of Arabidopsis thaliana, was previously shown to contain four direct repeats (Gap boxes, located between -237 and -181) that were necessary but not sufficient for light-activated gene transcription. To identify additional elements located between the Gap boxes and TATA box, various GAPB promoter fragments driving the beta-glucuronidase (GUS) reporter gene were constructed in transgenic Arabidopsis. We found a 23 bp element (the XXIII element), centered at -119, that is essential for promoter activity. Mutations in the XXIII element abolished transcription of GAPB completely. Furthermore, we have identified three additional elements, PI, Tboxes, and PII that serve as positive modulators in the light-activated transcription of GAPB. Mutations in any of these three elements resulted in the reduction in light inducibility of the GAPB gene. The PI, XXIII, Tboxes and PII sequences are novel cis-acting elements that are not present in the closely related GAPA promoter or other promoters that are similarly regulated by light. In our current study, we found that transgenic Arabidopsis containing a GAPB promoter::GUS construct with all four Gap boxes deleted exhibited significant GUS expression albeit reduced to 42% of the optimal expression level. In contrast, in previous studies on transgenic tobacco, total abolishment of GUS expression was seen when the Gap boxes were deleted. This suggests that different trans-acting factors present in heterologous systems may result in variability of the expression of the transgene.