Kinetics of transient hiatus hernia during transient lower esophageal sphincter relaxations and swallows in healthy subjects

BACKGROUND

Proximal displacement of the gastro-esophageal junction (GEJ) is present in hiatus hernia but also occurs transiently during transient lower esophageal sphincter relaxations (TLESRs) and swallows. Using a novel magnetic-based technique we have performed detailed examination of the GEJ movement during TLESRs and swallows in healthy subjects.

METHODS

In 12 subjects, a magnet was endoscopically clipped to the GEJ and combined assembly of Hall-Effect locator probe and 36 channel high-resolution manometer passed nasally. After a test meal the subjects were studied for 90 min.

KEY RESULTS

The median amplitude of proximal movement of GEJ during TLESRs was 4.3 cm (1.6-8.8 cm) and this was substantially greater than during swallowing at 1.2 cm (0.4-2.7 cm), P = 0.002. With both TLESRs and swallows proximal GEJ movement coincided with lower esophageal sphincter (LES) relaxation and return to its original position occurred 4 s after return of LES tone. Kinetic modeling of the movement of the GEJ during TLESRs indicated two return phases with the initial return phase having the greater velocity (0.9 cm s(-1) ) and being strongly correlated with amplitude of proximal movement (r = 0.8, P < 0.001).

CONCLUSIONS & INFERENCES

The marked proximal GEJ migration during TLESRs represents very severe herniation of the GEJ. The rapid initial return of the GEJ following TLESRs when the crural diaphragm is relaxed and its correlation with amplitude suggest it is due to elastic recoil of the phreno-esophageal ligament. The marked stretching of the phreno-esophageal ligament during TLESRs may contribute to its weakening and development of established hiatus hernia.

The Kiss2 receptor (Kiss2r) gene in Southern Bluefin Tuna, Thunnus maccoyii and in Yellowtail Kingfish, Seriola lalandi - functional analysis and isolation of transcript variants

The kisspeptin system plays an essential role in reproductive function in vertebrates, particularly in the onset of puberty. We investigated the kisspeptin system in two Perciform teleosts, the Southern Bluefin Tuna (SBT; Thunnus maccoyii), and the Yellowtail Kingfish (YTK; Seriola lalandi), by characterising their kisspeptin 2 receptor (Kiss2r) genes. In addition to the full length Kiss2r cDNA sequences, we have isolated from SBT and YTK a transcript variant that retained an intron. We have further obtained three ytkKiss2r transcript variants that contained deletions. In vitro functional analysis of the full length SBT and YTK Kiss2r showed higher response to Kiss2-10 than to Kiss1-10, with stronger transduction via PKC than PKA. The full length ytkKiss2r and two deletion variants were differentially expressed in the brain of male, but not in female, juvenile YTK treated with increasing doses of Kiss2-10 peptide. In the gonads, the expression level of the ytkKiss2r transcripts did not vary significantly either in the male or female fish. This is the first time that transcript variants of the Kiss2r gene that contain deletions and show responsiveness to treatments with kisspeptin have been reported in any teleost.

Incidence and outcomes of pregnancy-associated cancer in Australia, 1994-2008: a population-based linkage study

Objective

To determine trends in pregnancy-associated cancer and associations between maternal cancer and pregnancy outcomes.

Design

Population-based cohort study.

Setting

New South Wales, Australia, 1994–2008.

Population

A total of 781 907 women and their 1 309 501 maternities.

Methods

Cancer and maternal information were obtained from linked cancer registry, birth and hospital records for the entire population. Generalised estimating equations with a logit link were used to examine associations between cancer risk factors and pregnancy outcomes.

Main outcome measures

Incidence of pregnancy-associated cancer (diagnosis during pregnancy or within 12 months of delivery), maternal morbidities, preterm birth, and small- and large-for-gestational-age (LGA).

Results

A total of 1798 new cancer diagnoses were identified, including 499 during pregnancy and 1299 postpartum. From 1994 to 2007, the crude incidence rate of pregnancy-associated cancer increased from 112.3 to 191.5 per 100 000 maternities (P < 0.001), and only 14% of the increase was explained by increasing maternal age. Cancer diagnosis was more common than expected in women aged 15–44 years (observed-to-expected ratio 1.49; 95% CI 1.42–1.56). Cancers were predominantly melanoma (33.3%) and breast cancer (21.0%). Women with cancer diagnosed during pregnancy had high rates of labour induction (28.5%), caesarean section (40.0%) and planned preterm birth (19.7%). Novel findings included a cancer association with multiple pregnancies (adjusted odds ratio 1.52, 95% CI 1.13–2.05) and LGA (aOR 1.47, 95% CI 1.14–1.89).

Conclusions

Pregnancy-associated cancers have increased, and this increase is only partially explained by increasing maternal age. Pregnancy increases women’s interaction with health services and the possibility for diagnosis, but may also influence tumour growth.

Cre transgene results in global attenuation of the cAMP/PKA pathway

Use of the cre transgene in in vivo mouse models to delete a specific 'floxed' allele is a well-accepted method for studying the effects of spatially or temporarily regulated genes. During the course of our investigation into the effect of cyclic adenosine 3',5'-monophosphate-dependent protein kinase A (PKA) expression on cell death, we found that cre expression either in cultured cell lines or in transgenic mice results in global changes in PKA target phosphorylation. This consequently alters gene expression profile and changes in cytokine secretion such as IL-6. These effects are dependent on its recombinase activity and can be attributed to the upregulation of specific inhibitors of PKA (PKI). These results may explain the cytotoxicity often associated with cre expression in many transgenic animals and may also explain many of the phenotypes observed in the context of Cre-mediated gene deletion. Our results may therefore influence the interpretation of data generated using the conventional cre transgenic system.

BCLAF1 is a radiation-induced H2AX-interacting partner involved in γH2AX-mediated regulation of apoptosis and DNA repair

H2AX, a histone H2A variant, has a key role in the cellular response to DNA double-strand breaks (DSBs). H2AX senses DSBs through rapid serine 139 phosphorylation, concurrently leading to the formation of phospho-(γ)H2AX foci with various proteins. However, in the cells with different sensitivity to ionizing radiation (IR)-induced DSBs, still incomplete are those specific proteins selectively recruited by γH2AX to decide different cell fates. Because the abundance of γH2AX indicates the extent of DSBs, we first identified IR-induced dose-dependent H2AX-interacting partners and found that Bcl-2-associated transcription factor 1 (BCLAF1/Btf) showed enhanced association with γH2AX only under high-dose radiation. In acutely irradiated cells, BCLAF1 promoted apoptosis of irreparable cells through disturbing p21-mediated inhibition of Caspase/cyclin E-dependent, mitochondrial-mediated pathways. Meanwhile, BCLAF1 co-localized with γH2AX foci in nuclei and stabilized the Ku70/DNA-PKcs complex therein, facilitating non-homologous end joining (NHEJ)-based DSB repair in surviving cells. In tumor cells, BCLAF1 was intrinsically suppressed, leading to formation of anti-apoptotic Ku70-Bax complexes and disruption of Ku70/DNA-PKcs complexes, all of which contribute to tumor-associated apoptotic resistance and cell survival with defective NHEJ DNA repair. For the first time, our studies reveal that, based on the extent of DNA damage, BCLAF1 is involved in the γH2AX-mediated regulation of apoptosis and DNA repair, and is a γH2AX-interacting tumor suppressor.

Overweight and obesity among Malay primary school children in Kota Bharu, Kelantan: parental beliefs, attitudes and child feeding practices

INTRODUCTION

The increasing prevalence of overweight and obesity among children has become a major public health problem in Malaysia. Parents play an important role in child feeding especially among younger children.

METHODS

A study was conducted to evaluate the beliefs, attitudes and practices in child feeding among parents of normal weight, as well as overweight and obese primary school children in Kelantan using the Child Feeding Questionnaire (CFQ). This cross-sectional study was carried out on 175 Malay children from three schools in Kota Bharu district in Kelantan.

RESULTS

This study showed that 13.1% of the children were overweight and obese. Scores for perceived parent weight (p < 0.05) and perceived child weight (p < 0.001) were significantly higher among parents of overweight and obese children compared to parents of children with normal body weight. However, the score for pressure to eat among parents of overweight and obese children was significantly lower (p < 0.05) than parents of normal weight children. The perceived child weight (r = 0.468, p < 0.01), perceived parental weight (r = 0.190, p < 0.05) and food restriction (r = 0.179, p < 0.05) factors were found to be positively correlated with children's body mass index (BMI), whereas pressure to eat factor (r = -0.355, p < 0.01) was negatively correlated with children's body mass index (BMI).

CONCLUSION

The findings showed that parental feeding practices were linked to children's weight status and childhood obesity. Therefore parents should be given education and guidance on appropriate child feeding practices to maintain their child's nutritional status on a healthy weight range.

High-resolution esophageal manometry: addressing thermal drift of the manoscan system

BACKGROUND

The high resolution esophageal manometry system manufactured by Sierra Scientific Instruments is widely used. The technology is liable to 'thermal drift', a change in measured pressure due to change in temperature. This study aims to characterize 'thermal drift' and minimize its impact.

METHODS

Response of the system to immediate temperature change (20 °C to 37 °C) was tested. Accuracy of pressure measurement over two hours at 37 °C was examined. Six repetitions were performed and median pressure change calculated for each sensor. Sensors were compared using Kruskal-Wallis test. Current correction processes were tested.

KEY RESULTS

There was a biphasic response of the system to body temperature: an immediate change in recorded pressure, 'thermal effect' and an ongoing pressure change with time, 'baseline drift'. Median thermal effect for all 36 sensors was 7 mmHg (IQR 3.8 mmHg). Median baseline drift was 11.1 mmHg (IQR 9.9 mmHg). Baseline drift varied between sensors but for a given sensor was linear. Interpolated thermal compensation, recommended for prolonged studies, corrects data assuming a linear drift of pressures. When pressures were corrected in this way, baseline pressure was almost restored to zero (Median 0.3 mmHg, IQR 0.3). The standard thermal compensation process did not address the error associated with baseline drift.

CONCLUSIONS & INFERENCES

Thermal effect is well compensated in the current operation of the system but baseline drift is not well recognized or addressed. Incorporation of a linear correction into current software would improve accuracy without impact on ease of use.

Urbanization and prevalence of depression in diabetes

OBJECTIVES

To depict recent secular trend (2001-2005) in prevalence of depression among diabetic population in Taiwan, and to explore the influences of urbanization on the prevalence of depression.

STUDY DESIGN

A descriptive correlation study design relating urbanization and prevalence of depression.

METHODS

Annual prevalence of depression was calculated as the ratio of number of individuals with depression (ICD-9-CM: 296, 309, or 311) to the size of diabetic population (ICD-9-CM: 250), which were ascertained from ambulatory care claim data of Taiwan's National Health Insurance between 2001 and 2005. Multivariate Poisson regression analysis was used to assess the secular trend in the prevalence of comorbid depression, and to appraise the influence of urbanization on prevalence of depression in diabetic patients.

RESULTS

The prevalence of depression among diabetic population increased annually from 22.6/10(3) in 2001 to 27.0/10(3) in 2005 with a significantly and linearly rising trend (β = 0.0461, p < 0.0001). Diabetic population living in urban areas showed the largest increase in prevalence (6.3/10(3)), followed by those from rural areas (5.6/10(3)). Compared to the diabetic patients residing in rural areas, those living in urban areas (RR = 1.28, 95% CI = 1.25-1.31) and those from satellite towns (RR = 1.22, 95% CI = 1.19-1.25) both had significantly increased adjusted RR.

CONCLUSIONS

There is a significant increasing trend in prevalence of depression among diabetic population in recent years in Taiwan. Diabetic patients from urban areas not only had the greatest prevalence of depression but also showed the largest increase in prevalence during the study period, which highlights a need for managing depression in urban diabetes.

Surface and ultrastructural characterization of raw and pretreated switchgrass

The US Department of Energy-funded Biomass Refining CAFI (Consortium for Applied Fundamentals and Innovation) project has developed leading pretreatment technologies for application to switchgrass and has evaluated their effectiveness in recovering sugars from the coupled operations of pretreatment and enzymatic hydrolysis. Key chemical and physical characteristics have been determined for pretreated switchgrass samples. Several analytical microscopy approaches utilizing instruments in the Biomass Surface Characterization Laboratory (BSCL) at the National Renewable Energy Laboratory (NREL) have been applied to untreated and CAFI-pretreated switchgrass samples. The results of this work have shown that each of the CAFI pretreatment approaches on switchgrass result in different structural impacts at the plant tissue, cellular, and cell wall levels. Some of these structural changes can be related to changes in chemical composition upon pretreatment. There are also apparently different structural mechanisms that are responsible for achieving the highest enzymatic hydrolysis sugar yields.

Process and technoeconomic analysis of leading pretreatment technologies for lignocellulosic ethanol production using switchgrass

Six biomass pretreatment processes to convert switchgrass to fermentable sugars and ultimately to cellulosic ethanol are compared on a consistent basis in this technoeconomic analysis. The six pretreatment processes are ammonia fiber expansion (AFEX), dilute acid (DA), lime, liquid hot water (LHW), soaking in aqueous ammonia (SAA), and sulfur dioxide-impregnated steam explosion (SO(2)). Each pretreatment process is modeled in the framework of an existing biochemical design model so that systematic variations of process-related changes are consistently captured. The pretreatment area process design and simulation are based on the research data generated within the Biomass Refining Consortium for Applied Fundamentals and Innovation (CAFI) 3 project. Overall ethanol production, total capital investment, and minimum ethanol selling price (MESP) are reported along with selected sensitivity analysis. The results show limited differentiation between the projected economic performances of the pretreatment options, except for processes that exhibit significantly lower monomer sugar and resulting ethanol yields.

Application of cellulase and hemicellulase to pure xylan, pure cellulose, and switchgrass solids from leading pretreatments

Accellerase 1000 cellulase, Spezyme CP cellulase, β-glucosidase, Multifect xylanase, and beta-xylosidase were evaluated for hydrolysis of pure cellulose, pure xylan, and switchgrass solids from leading pretreatments of dilute sulfuric acid, sulfur dioxide, liquid hot water, lime, soaking in aqueous ammonia, and ammonia fiber expansion. Distinctive sugar release patterns were observed from Avicel, phosphoric acid swollen cellulose (PASC), xylan, and pretreated switchgrass solids, with accumulation of significant amounts of xylooligomers during xylan hydrolysis. The strong inhibition of cellulose hydrolysis by xylooligomers could be partially attributed to the negative impact of xylooligomers on cellulase adsorption. The digestibility of pretreated switchgrass varied with pretreatment but could not be consistently correlated to xylan, lignin, or acetyl removal. Initial hydrolysis rates did correlate well with cellulase adsorption capacities for all pretreatments except lime, but more investigation is needed to relate this behavior to physical and compositional properties of pretreated switchgrass.

Effects of enzyme loading and β-glucosidase supplementation on enzymatic hydrolysis of switchgrass processed by leading pretreatment technologies

The objective of this work is to investigate the effects of cellulase loading and β-glucosidase supplementation on enzymatic hydrolysis of pretreated Dacotah switchgrass. To assess the difference among various pretreatment methods, the profiles of sugars and intermediates were determined for differently treated substrates. For all pretreatments, 72 h glucan/xylan digestibilities increased sharply with enzyme loading up to 25mg protein/g-glucan, after which the response varied depending on the pretreatment method. For a fixed level of enzyme loading, dilute sulfuric acid (DA), SO(2), and Lime pretreatments exhibited higher digestibility than the soaking in aqueous ammonia (SAA) and ammonia fiber expansion (AFEX). Supplementation of Novozyme-188 to Spezyme-CP improved the 72 h glucan digestibility only for the SAA treated samples. The effect of β-glucosidase supplementation was discernible only at the early phase of hydrolysis where accumulation of cellobiose and oligomers is significant. Addition of β-glucosidase increased the xylan digestibility of alkaline treated samples due to the β-xylosidase activity present in Novozyme-188.

Comparative study on enzymatic digestibility of switchgrass varieties and harvests processed by leading pretreatment technologies

Feedstock quality of switchgrass for biofuel production depends on many factors such as morphological types, geographic origins, maturity, environmental and cultivation parameters, and storage. We report variability in compositions and enzymatic digestion efficiencies for three cultivars of switchgrass (Alamo, Dacotah and Shawnee), grown and harvested at different locations and seasons. Saccharification yields of switchgrass processed by different pretreatment technologies (AFEX, dilute sulfuric acid, liquid hot water, lime, and soaking in aqueous ammonia) are compared in regards to switchgrass genotypes and harvest seasons. Despite its higher cellulose content per dry mass, Dacotah switchgrass harvested after wintering consistently gave a lower saccharification yield than the other two varieties harvested in the fall. The recalcitrance of upland cultivars and over-wintered switchgrass may require more severe pretreatment conditions. We discuss the key features of different pretreatment technologies and differences in switchgrass cultivars and harvest seasons on hydrolysis performance for the applied pretreatment methods.

Comparative material balances around pretreatment technologies for the conversion of switchgrass to soluble sugars

For this project, six chemical pretreatments were compared for the Consortium for Applied Fundamentals and Innovation (CAFI): ammonia fiber expansion (AFEX), dilute sulfuric acid (DA), lime, liquid hot water (LHW), soaking in aqueous ammonia (SAA), and sulfur dioxide (SO(2)). For each pretreatment, a material balance was analyzed around the pretreatment, optional post-washing step, and enzymatic hydrolysis of Dacotah switchgrass. All pretreatments+enzymatic hydrolysis solubilized over two-thirds of the available glucan and xylan. Lime, post-washed LHW, and SO(2) achieved >83% total glucose yields. Lime, post-washed AFEX, and DA achieved >83% total xylose yields. Alkaline pretreatments, except AFEX, solubilized the most lignin and a portion of the xylan as xylo-oligomers. As pretreatment pH decreased, total solubilized xylan and released monomeric xylose increased. Low temperature-long time or high temperature-short time pretreatments are necessary for high glucose release from late-harvest Dacotah switchgrass but high temperatures may cause xylose degradation.

Investigation of enzyme formulation on pretreated switchgrass

This work studied the benefits of adding different enzyme cocktails (cellulase, xylanase, β-glucosidase) to pretreated switchgrass. Pretreatment methods included ammonia fiber expansion (AFEX), dilute-acid (DA), liquid hot water (LHW), lime, lime+ball-milling, soaking in aqueous ammonia (SAA), and sulfur dioxide (SO(2)). The compositions of the pretreated materials were analyzed and showed a strong correlation between initial xylan composition and the benefits of xylanase addition. Adding xylanase dramatically improved xylan yields for SAA (+8.4%) and AFEX (+6.3%), and showed negligible improvement (0-2%) for the pretreatments with low xylan content (dilute-acid, SO(2)). Xylanase addition also improved overall yields with lime+ball-milling and SO(2) achieving the highest overall yields from pretreated biomass (98.3% and 93.2%, respectively). Lime+ball-milling obtained an enzymatic yield of 92.3kg of sugar digested/kg of protein loaded.

Comparative data on effects of leading pretreatments and enzyme loadings and formulations on sugar yields from different switchgrass sources

Dilute sulfuric acid (DA), sulfur dioxide (SO(2)), liquid hot water (LHW), soaking in aqueous ammonia (SAA), ammonia fiber expansion (AFEX), and lime pretreatments were applied to Alamo, Dacotah, and Shawnee switchgrass. Application of the same analytical methods and material balance approaches facilitated meaningful comparisons of glucose and xylose yields from combined pretreatment and enzymatic hydrolysis. Use of a common supply of cellulase, beta-glucosidase, and xylanase also eased comparisons. All pretreatments enhanced sugar recovery from pretreatment and subsequent enzymatic hydrolysis substantially compared to untreated switchgrass. Adding beta-glucosidase was effective early in enzymatic hydrolysis while cellobiose levels were high but had limited effect on longer term yields at the enzyme loadings applied. Adding xylanase improved yields most for higher pH pretreatments where more xylan was left in the solids. Harvest time had more impact on performance than switchgrass variety, and microscopy showed changes in different features could impact performance by different pretreatments.

WITHDRAWN: Comparative Data on Effects of Leading Pretreatments and Enzyme Loadings and Formulations on Sugar Yields from Different Switchgrass Sources

This article has been withdrawn at the request of the author(s) and/or editor. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at http://www.elsevier.com/locate/withdrawalpolicy.

Dietary practices among overweight and obese Chinese children in Kota Bharu, Kelantan

INTRDUCTION: Obesity and chronic diseases have been increasing since the last few decades alongside rapid economic development in developed and developing countries. The alarming increase in the prevalence of childhood obesity had been shown by many epidemiological studies worldwide. The aims of this study were to determine the prevalence of overweight and obesity among Chinese school children in Kota Bharu, Kelantan, and to map the association between dietary practices and their nutritional status.

METHODS

A cross-sectional study was conducted on 278 school children aged 10 to 12 years old (144 boys and 134 girls) studying in a Chinese primary school in Kota Bharu.

RESULTS

The survey revealed that while only 1.4% (n=4) were overweight, 23.4% (n=65) of the children were obese. A total of 67.7% (n=44) of the obese children were boys. The overweight and obese children (n=70) were compared with a randomly selected group of normal weight children (n=70). Dietary assessment showed that protein, fat and total calorie intake were significantly higher among the overweight group (p<0.05). A significantly higher proportion of the normal weight children (85.7%) took breakfast daily or at least 4 days per week compared to the overweight groups (59.4%) (p<0.05).

CONCLUSION

The prevalence of obesity among school children in the study is a matter of concern. These findings may be useful in targeting programmes and strategies for prevention and intervention of childhood obesity.

Biologic characteristics of bone marrow-derived mesenchymal stem cells from a patient with thalassemia syndrome

INTRODUCTION

Mesenchymal stem cells (MSCs) are capable of self-renewal and differentiating morphologically and functionally into several mesenchymal tissues. There have been contrasting data on whether MSCs are altered in various hematologic disorders.

METHODS

We isolated bone marrow (BM)-derived MSCs from a patient with thalassemia syndrome to compare phenotypic and functional characteristics to those from normal healthy donor.

RESULTS

No differences were observed between MSCs from thalassemia syndrome (T-MSCs) and those from normal healthy donor in terms of morphology, phenotype, karyotype, multidifferentiation capacity. In mixed lymphocyte reaction, T-MSCs strongly inhibited the proliferation of allogeneic T cells in association with reduced proportion of CD3(+), CD4(+), and CD8(+) cells. Furthermore, the fraction of Treg cells was increased under the culture with T-MSCs, suggesting that T-MSCs exert normal immunomodulatory function. In addition, T-MSCs expressed hematopoietic cytokines and supported hematopoiesis, which was comparable to those from normal BM-derived MSCs.

CONCLUSION

T-MSCs exhibited normal phenotype, karyotype as well as normal immunomodulatory function, and autologous MSCs from patients with thalassemia syndrome may be an attractive source of stem cell in terms of hematopoietic support as well as immunomodulatory activity.

Pretreatment of corn stover and hybrid poplar by sodium hydroxide and hydrogen peroxide

Sodium hydroxide and its derivatives are used as pulping reagents, wherein the spent NaOH is recovered in salt form and reused. In this study, use of low concentration NaOH (1-5%) in pretreatment of corn stover and hybrid poplar was investigated. It was done with the understanding that NaOH can be recovered. One of the main objectives in this study is to explore the potential of H(2)O(2) with NaOH for pretreatment of high lignin substrate such as hybrid poplar. Pretreatment time has not been optimized in this study but held constant at 24 h. Corn stover, after treatment with NaOH under moderate conditions, attains near quantitative glucan digestibility. On the other hand, hybrid poplar requires treatment at higher temperature and NaOH concentration to attain acceptable level of digestibility. Supplementation of hydrogen peroxide in the pretreatment significantly raises delignification and digestibility of hybrid poplar. It was also helpful in retaining the carbohydrates in the treated solids. Retention of hemicellulose after pretreatment provides a significant economic benefit as it eliminates the need for detoxifying hemicellulose sugars. As the residual xylan remaining after pretreatment is an impediment to enzymatic digestion of glucan, supplementation of xylanase has significantly increased the digestibility of glucan as well as xylan of the treated hybrid poplar.

Unusual manifestation of cutaneous toxoplasmosis in a HIV-positive patient

We report a case of unusual cutaneous toxoplasmosis manifestation in a HIV-positive patient. He presented with hard and painful nodular lesions on the arms, hands and chest. Serology tests for anti-Toxoplasma antibody were negative. However, histopathologic examination of the lesion revealed foci of macrophages containing crescent-shaped organisms resembling the zoites of the protozoan parasite Toxoplasma gondii. Ultrastructure examination under electron microscopy and PCR confirmed the organism as T. gondii.

MUC1 enhances invasiveness of pancreatic cancer cells by inducing epithelial to mesenchymal transition

Increased motility and invasiveness of pancreatic cancer cells are associated with epithelial to mesenchymal transition (EMT). Snai1 and Slug are zinc-finger transcription factors that trigger this process by repressing E-cadherin and enhancing vimentin and N-cadherin protein expression. However, the mechanisms that regulate this activation in pancreatic tumors remain elusive. MUC1, a transmembrane mucin glycoprotein, is associated with the most invasive forms of pancreatic ductal adenocarcinomas (PDA). In this study, we show that over expression of MUC1 in pancreatic cancer cells triggers the molecular process of EMT, which translates to increased invasiveness and metastasis. EMT was significantly reduced when MUC1 was genetically deleted in a mouse model of PDA or when all seven tyrosines in the cytoplasmic tail of MUC1 were mutated to phenylalanine (mutated MUC1 CT). Using proteomics, RT-PCR and western blotting, we revealed a significant increase in vimentin, Slug and Snail expression with repression of E-Cadherin in MUC1-expressing cells compared with cells expressing the mutated MUC1 CT. In the cells that carried the mutated MUC1 CT, MUC1 failed to co-immunoprecipitate with β-catenin and translocate to the nucleus, thereby blocking transcription of the genes associated with EMT and metastasis. Thus, functional tyrosines are critical in stimulating the interactions between MUC1 and β-catenin and their nuclear translocation to initiate the process of EMT. This study signifies the oncogenic role of MUC1 CT and is the first to identify a direct role of the MUC1 in initiating EMT during pancreatic cancer. The data may have implications in future design of MUC1-targeted therapies for pancreatic cancer.

Investigation of biomass degradation mechanism in pretreatment of switchgrass by aqueous ammonia and sodium hydroxide

Pretreatment of switchgrass using aqueous ammonia or NaOH was investigated as a means to enhance the enzymatic digestibility. To increase the effectiveness of pretreatment, H(2)O(2) was supplemented with the alkaline reagents. Since H(2)O(2) is unstable at high temperature, low-to-high step-change of temperature was applied, and this scheme was found to be effective in the case of NH(3)/H(2)O(2) treatment. The composition of pretreatment liquid indicates that hemicellulose solubilized during alkaline treatment exists either in the form of oligomers or as lignin-carbohydrate complex (LCC). LCC formation was prominent in ammonia treatment and in NaOH/H(2)O(2) treatment, and that LCC formation protects the hemicelluloses sugars from degradation. Lignin in the pretreatment liquor was precipitated and subjected to TGA and FTIR analyses. TGA data indicate that NaOH-lignin has more uniform structure and higher O/C ratio than ammonia-lignin. FTIR analysis indicates that NaOH-lignin has lower aromatic content but higher guaiacyl type structure than ammonia-lignin.

HLA polymorphism in three indigenous populations of Sabah and Sarawak

One hundred and fifty-eight Kadazan, Iban and Bidayuh individuals registered with the Malaysian Marrow Donor Registry were typed for human leukocyte antigen (HLA)-A, HLA-B and HLA-DR. Six, seven and eight HLA-A alleles as well as 13, 15 and 16 HLA-B alleles were detected in the Kadazan, Bidayuh and Iban, respectively. The most common HLA-A allele in all three groups was HLA-A*24 with a frequency of 0.456, 0.490 and 0.422 in the Kadazan, Bidayuh and Iban, respectively. The most common HLA-B allele detected in the Kadazan was HLA-B*40 with a frequency of 0.333; for the Bidayuh and the Iban it was HLA-B*15 with a frequency of 0.460 and 0.275, respectively. The HLA-DR allele with the highest frequency in the Kadazan was HLA-DR*1502 with a frequency of 0.500. In the Iban and the Bidayuh, HLA-DRB1*1202 was the most common DR allele with frequencies of 0.235 and 0.310, respectively. The two most common haplotypes for the Kadazan are A*34-B*38-DR*1502 and A*24-B*40-DR*0405, whereas for the Bidayuh they are A*24-B*15-DR*1602 and A*24-B*35-DR*1202 and for the Iban they are A*34-*B15-DR*1502 and A*24-B*15-DR*1202.

Cellulose pretreatment in subcritical water: effect of temperature on molecular structure and enzymatic reactivity

Microcrystalline cellulose (MCC) was pretreated with subcritical water in a continuous flow reactor for enhancing its enzymatic reactivity with cellulase enzyme. Cellulose/water suspension was mixed with subcritical (i.e., pressurized and heated) water and then fed into the reactor maintained at a constant temperature and pressure. After the reaction, product was immediately cooled in a double-pipe heat exchanger. The solid portion of the product (i.e., treated MCC) was separated and tested for molecular structure and enzymatic reactivity. Experiments were conducted at temperatures ranging from 200 to 315 degrees C, at 27.6 MPa, and for 3.4-6.2 s reaction times. The treated MCC was characterized for degree of polymerization (DP(v)) by viscosimetry, and crystallinity by X-ray diffraction (XRD). In addition, differential scanning calorimetry and scanning electron microscopy (SEM) analyses were carried out to study any transformation in the cellulose structure. As expected, DP(v) of cellulose steadily decreased with increase in the pretreatment temperature, with a rapid drop occurring above 300 degrees C. On the other hand, XRD analysis did not show any decrease in crystallinity upon pretreatment but, partial transformation of celluloses I-II structure was noticed in the MCC treated at 300 degrees C. Development of surface cracks and trenches were observed in the SEM images for all the treated samples. Enzymatic reactivity was increased after the treatment at > or = 300 degrees C.