bluuebunny/crossref_metadata_2025 huggingface dataset:
Inhibition of c-Met and prevention of spontaneous metastatic spreading by the 2-indolinone RPI-1
Authors: Cassinelli Giuliana , Lanzi Cinzia , Petrangolini Giovanna , Tortoreto Monica , Pratesi Graziella , Cuccuru Giuditta , Laccabue Diletta , Supino Rosanna , Belluco Sara , Favini Enrica , Poletti Anna , Zunino Franco
Published: September 2006

Hepatocyte growth factor (HGF) and its tyrosine kinase receptor Met play a pivotal role in the tumor metastatic phenotype and represent attractive therapeutic targets. We investigated the biochemical and biological effects of the tyrosine kinase inhibitor RPI-1 on the human lung cancer cell lines H460 and N592, which express constitutively active Met. RPI-1-treated cells showed down-regulation of Met activation and expression, inhibition of HGF/Met-dependent downstream signaling involving AKT, signal transducers and activators of transcription 3 and paxillin, as well as a reduced expression of the proangiogenic factors vascular endothelial growth factor and basic fibroblast growth factor. Cell growth in soft agar of H460 cells was strongly reduced in the presence of the drug. Furthermore, RPI-1 inhibited both spontaneous and HGF-induced motility/invasiveness of both H460 and human endothelial cells. Targeting of Met signaling by alternative methods (Met small interfering RNA and anti-phosphorylated Met antibody intracellular transfer) produced comparable biochemical and biological effects. Using the spontaneously metastasizing lung carcinoma xenograft H460, daily oral treatment with well-tolerated doses of RPI-1 produced a significant reduction of spontaneous lung metastases (−75%; P < 0.001, compared with control mice). In addition, a significant inhibition of angiogenesis in primary s.c. tumors of treated mice was observed, possibly contributing to limit the development of metastases. The results provide preclinical evidence in support of Met targeting pharmacologic approach as a new option for the control of tumor metastatic dissemination. [Mol Cancer Ther 2006;5(9):2388–97]
Angiotensin II Type 2 Receptor Expression After Vascular Injury
Authors: Barker Thomas A. , Massett Michael P. , Korshunov Vyacheslav A. , Mohan Amy M. , Kennedy Amy J. , Berk Bradford C.
Published: September 2006

It has been suggested that the effects of angiotensin II type 1 receptor (AT1R) blockers are in part because of angiotensin II type 2 receptor (AT2R) signaling. Interactions between the AT2R and kinins modulate cardiovascular function. Because AT2R expression increases after vascular injury, we hypothesized that the effects on vascular remodeling of the AT1R blocker valsartan and the ACE inhibitor benazepril require AT2R signaling through the bradykinin 1 and 2 receptors (B1R and B2R). To test this hypothesis, Brown Norway rats were assigned to 8 treatments (n=16): valsartan, valsartan+PD123319 (AT2R inhibitor), valsartan+des-arg9-[Leu8]-bradykinin (B1R inhibitor), valsartan+HOE140 (B2R inhibitor), benazepril, benazepril+HOE140, amlodipine, and vehicle. After 1 week of treatment, carotid balloon injury was performed. Two weeks later, carotids were harvested for morphometry and analysis of receptor expression by immunohistochemistry and Western blotting. Valsartan and benazepril significantly reduced the intima:media ratio compared with vehicle. Blockade of AT2R, B1R, or B2R in the presence of valsartan prevented the reduction seen with valsartan alone. B2R blockade inhibited the effect of benazepril. Injury increased AT1R, AT2R, B1R, and B2R expression. Treatment with valsartan but not benazepril significantly increased intima AT2R expression 2-fold compared with vehicle, which was not reversed by inhibition of AT2R, B1R, and B2R. Functionally, valsartan increased intimal cGMP levels compared with vehicle, and this increase was inhibited by blocking the AT2R, B1R, and B2R. Results suggest that AT2R expression and increased cGMP represent a molecular mechanism that differentiates AT1R blockers, such as valsartan, from angiotensin-converting enzyme inhibitors like benazepril.
Soluble Guanylate Cyclase Stimulation on Cardiovascular Remodeling in Angiotensin II–Induced Hypertensive Rats
Authors: Masuyama Hiroyuki , Tsuruda Toshihiro , Kato Johji , Imamura Takuroh , Asada Yujiro , Stasch Johannes-Peter , Kitamura Kazuo , Eto Tanenao
Published: September 2006

It is unknown whether long-term pharmacological stimulation of soluble guanylate cyclase (sGC), elevating intracellular cGMP levels, has a beneficial effect on hypertension. The purpose of this study is to investigate the effects of BAY41-2272, an orally available sGC stimulator, on cardiovascular remodeling in hypertensive rats. Eight-week-old male Wistar rats with hypertension induced by angiotensin II infused subcutaneously at 250 ng/kg per minute were treated orally with a low ([L] 2 mg/kg per day) or high ([H] 10 mg/kg per day) dose of BAY41-2272 for 14 days. BAY41-2272-H partially suppressed the rise in blood pressure and reduced the heart weight (4.20±0.34 versus 3.68±0.20 mg/g;
P
<0.01), whereas BAY41-2272-L had no effect. However, both doses decreased the angiotensin II–induced left ventricular accumulation of collagen in the perivascular area (L, −20%,
P
<0.05; H, −30%,
P
<0.01) and myocardial interstitium (L, −21%,
P
<0.05; H, −38%,
P
<0.01), reducing the number of activated fibroblasts surrounding coronary arteries (L, −74%; H, −79%;
P
<0.05). BAY41-2272 downregulated the angiotensin II–induced left ventricular gene expression of type 1 collagen (L, −41%,
P
<0.05; H, −49%,
P
<0.01) and transforming growth factor-β1 (L, −49%,
P
<0.05; H, −65%,
P
<0.01). cGMP levels were elevated by BAY41-2272 not only in the left ventricle, but also in cultured cardiac fibroblasts, resulting in reduced thymidine incorporation into the cells. Thus, stimulation of sGC by BAY41-2272 attenuates fibrosis of the left ventricle in rats with angiotensin II–induced hypertension partly in a pressure-independent manner, suggesting an important role for sGC generating cGMP in inhibiting cardiovascular remodeling.
Predicting Stroke Using 4 Ambulatory Blood Pressure Monitoring-Derived Blood Pressure Indices
Authors: Inoue Ryusuke , Ohkubo Takayoshi , Kikuya Masahiro , Metoki Hirohito , Asayama Kei , Obara Taku , Hoshi Haruhisa , Hashimoto Junichiro , Totsune Kazuhito , Satoh Hiroshi , Kondo Yoshiaki , Imai Yutaka
Published: September 2006

We investigated the association between stroke and blood pressure (BP) indices (systolic BP [SBP], diastolic BP [DBP], mean BP [MBP], and pulse pressure [PP]) determined by ambulatory BP monitoring. The predictive power for stroke of these indices was compared in the general Japanese population. We obtained ambulatory BP data in 1271 subjects (40% men) aged ≥40 (mean: 61) years. During a mean follow-up of 11 years, 113 strokes were observed. The multivariate adjusted relative hazard and likelihood ratio for a 1-SD increase for each BP index was determined by Cox proportional hazard regression. Comparison of the likelihood ratio between Cox models including 2 indices and those including 1 index indicated that PP was significantly less informative than other indices (
P
<0.01 when adding MBP, SBP, or DBP to the PP model;
P
>0.09 when adding PP to the model including another index). However, after removing age from covariates, PP became more informative than DBP and MBP (
P
<0.0001 when adding PP to the MBP or DBP model, whereas SBP was more informative than PP even after removing age;
P
<0.05 when adding SBP to the PP model). In conclusion, PP was the weakest predictor of stroke. Exclusion of age from covariates increased the predictive power of PP, suggesting that the stroke risk associated with PP reflected the risk of aging per se.
Destination brands vs destination images: Do we know what we mean?
Authors: Tasci Asli D. A. , Kozak Metin
Published: September 2006

A review of the literature on branding in general, and on destination branding more specifically, raises several questions about the branding of tourist destinations. What is clear is that confusion exists in the concept of ‘brand’ in the tourist destination context. This panel study was designed to explore how experts perceive the meaning of destination branding and its main characteristics. Five propositions were developed and explored in regards to the lack of clear definition of destination brand, the confusion between brand and image, the lack of conception of similarities and differences between branding for consumer products and tourist destinations, the difficulty of identifying one symbol for countries, and the lack of commonly-known brands of tourist destinations. This article then proposes a model of branding and its ramifications in the tourism destination context, as well as providing several methodological, theoretical and practical implications.
Travel decisions of students at a US university: Segmenting the international market
Authors: Kim Kakyom , Jogaratnam Giri , Noh Jeonghee
Published: September 2006

Travel motivation is an important concept in understanding why and how individuals make travel decisions to preferred destinations. A total of 469 responses obtained from students at a US university were analyzed to determine push and pull motivation factors toward the top 10 overseas destinations and to assess if there were significant differences in the factors across the destinations. Analysis identified seven push and six pull factors and found substantial differences in the factors across the destinations. Marketing plans and implications are suggested for promoting travel products targeting the student market.
The value of visitor surveys: The case of Norfolk Island
Authors: Prideaux Bruce , Crosswell Melanie
Published: September 2006

This article reports on research undertaken to establish a socio-demographic profile of Australian tourists visiting Norfolk Island, an Australian Dependency located in the South Pacific Ocean. Prior to this research the island’s tourism industry has not had available a detailed profile of its visitors or their motivations for travelling to the destination and, in the absence of data of this nature, had relied on their collective assumptions about the market. Before conducting a visitors survey, members of the island’s tourism industry were interviewed and the assumptions they relied on for developing marketing strategies were identified. Many of the assumptions were not valid. As one example, the industry assumed that most visitors had visited the island previously. Findings indicated that only 18 per cent of the survey respondents fell into this category. The article highlights the need for accurate quantitative research data as the basis for market segmentation and marketing strategy development.
Detecting recombination in evolving nucleotide sequences
Authors: Chan Cheong Xin , Beiko Robert G , Ragan Mark A
Published: September 2006

Background

Genetic recombination can produce heterogeneous phylogenetic histories within a set of homologous genes. These recombination events can be obscured by subsequent residue substitutions, which consequently complicate their detection. While there are many algorithms for the identification of recombination events, little is known about the effects of subsequent substitutions on the accuracy of available recombination-detection approaches.

Results

We assessed the effect of subsequent substitutions on the detection of simulated recombination events within sets of four nucleotide sequences under a homogeneous evolutionary model. The amount of subsequent substitutions per site, prior evolutionary history of the sequences, and reciprocality or non-reciprocality of the recombination event all affected the accuracy of the recombination-detecting programs examined. Bayesian phylogenetic-based approaches showed high accuracy in detecting evidence of recombination event and in identifying recombination breakpoints. These approaches were less sensitive to parameter settings than other methods we tested, making them easier to apply to various data sets in a consistent manner.

Conclusion

Post-recombination substitutions tend to diminish the predictive accuracy of recombination-detecting programs. The best method for detecting recombined regions is not necessarily the most accurate in identifying recombination breakpoints. For difficult detection problems involving highly divergent sequences or large data sets, different types of approach can be run in succession to increase efficiency, and can potentially yield better predictive accuracy than any single method used in isolation.
Comparison of methods for genomic localization of gene trap sequences
Authors: Harper Courtney A , Huang Conrad C , Stryke Doug , Kawamoto Michiko , Ferrin Thomas E , Babbitt Patricia C
Published: September 2006

Background

Gene knockouts in a model organism such as mouse provide a valuable resource for the study of basic biology and human disease. Determining which gene has been inactivated by an untargeted gene trapping event poses a challenging annotation problem because gene trap sequence tags, which represent sequence near the vector insertion site of a trapped gene, are typically short and often contain unresolved residues. To understand better the localization of these sequences on the mouse genome, we compared stand-alone versions of the alignment programs BLAT, SSAHA, and MegaBLAST. A set of 3,369 sequence tags was aligned to build 34 of the mouse genome using default parameters for each algorithm. Known genome coordinates for the cognate set of full-length genes (1,659 sequences) were used to evaluate localization results.

Results

In general, all three programs performed well in terms of localizing sequences to a general region of the genome, with only relatively subtle errors identified for a small proportion of the sequence tags. However, large differences in performance were noted with regard to correctly identifying exon boundaries. BLAT correctly identified the vast majority of exon boundaries, while SSAHA and MegaBLAST missed the majority of exon boundaries. SSAHA consistently reported the fewest false positives and is the fastest algorithm. MegaBLAST was comparable to BLAT in speed, but was the most susceptible to localizing sequence tags incorrectly to pseudogenes.

Conclusion

The differences in performance for sequence tags and full-length reference sequences were surprisingly small. Characteristic variations in localization results for each program were noted that affect the localization of sequence at exon boundaries, in particular.
Plasma membrane calcium ATPase (PMCA4): A housekeeper for RT-PCR relative quantification of polytopic membrane proteins
Authors: Calcagno Anna Maria , Chewning Katherine J , Wu Chung-Pu , Ambudkar Suresh V
Published: September 2006

Background

Although relative quantification of real-time RT-PCR data can provide valuable information, one limitation remains the selection of an appropriate reference gene. No one gene has emerged as a universal reference gene and much debate surrounds some of the more commonly used reference genes, such as glyceraldehyde-3-phosphate dehydrogenase (GAPDH). At this time, no gene encoding for a plasma membrane protein serves as a reference gene, and relative quantification of plasma membrane proteins is performed with genes encoding soluble proteins, which differ greatly in quantity and in targeting and trafficking from plasma membrane proteins. In this work, our aim was to identify a housekeeping gene, ideally one that codes for a plasma membrane protein, whose expression remains the same regardless of drug treatment and across a wide range of tissues to be used for relative quantification of real-time RT-PCR data for ATP binding cassette (ABC) plasma membrane transporters.

Results

In studies evaluating the expression levels of two commonly used reference genes coding for soluble proteins and two genes coding for membrane proteins, one plasma membrane protein, plasma membrane calcium-ATPase 4 (PMCA4), was comparable to the two reference genes already in use. In addition, PMCA4 expression shows little variation across eight drug-treated cell lines and was found to be superior to GAPDH and HPRT1, commonly used reference genes. Finally, we show PMCA4 used as a reference gene for normalizing ABC transporter expression in a drug-resistant lung carcinoma cell line.

Conclusion

We have found that PMCA4 is a good housekeeping gene for normalization of gene expression for polytopic membrane proteins including transporters and receptors.
Bowel cancer screening in England: a qualitative study of GPs' attitudes and information needs
Authors: Woodrow Chris , Rozmovits Linda , Hewitson Paul , Rose Peter , Austoker Joan , Watson Eila
Published: September 2006

Background

The National Health Service Bowel Cancer Screening Programme is to be introduced in England during 2006. General Practitioners are a potentially important point of contact for participants throughout the screening process. The aims of the study were to examine GPs' attitudes and information needs with regard to bowel cancer screening, with a view to developing an information pack for primary care teams that will be circulated prior to the introduction of the programme.

Methods

32 GPs participated in semi-structured telephone interviews. 18 of these had participated in the English Bowel Screening Pilot, and 14 had not. Interviews covered attitudes towards the introduction of the Bowel Cancer Screening Programme, expected or actual increases in workload, confidence in promoting informed choice, and preferences for receiving information about the programme.

Results

GPs in the study were generally positive about the introduction of the Bowel Cancer Screening Programme. A number of concerns were identified by GPs who had not taken part in the pilot programme, particularly relating to patient welfare, patient participation, and increased workload. GPs who had taken part in the pilot reported holding similar concerns prior to their involvement. However, in many cases these concerns were not confirmed through GPs experiences with the pilot. A number of specific information needs were identified by GPs to enable them to provide a supportive role to participants in the programme.

Conclusion

The study has found considerable GP support for the introduction of the new Bowel Cancer Screening Programme. Nonetheless, GPs hold some significant reservations regarding the programme. It is important that the information needs of GPs and other members of the primary care team are addressed prior to the roll-out of the programme so they are equipped to promote informed choice and provide support to patients who consult them with queries regarding screening.
Overweight, physical activity, tobacco and alcohol consumption in a cross-sectional random sample of German adults
Authors: Haenle Mark M , Brockmann Stefan O , Kron Martina , Bertling Ursula , Mason Richard A , Steinbach Gerald , Boehm Bernhard O , Koenig Wolfgang , Kern Peter , Piechotowski Isolde , Kratzer Wolfgang ,   the EMIL-Study group
Published: September 2006

Background

There is a current paucity of data on the health behaviour of non-selected populations in Central Europe. Data on health behaviour were collected as part of the EMIL study which investigated the prevalence of infection with Echinococcus multilocularis and other medical conditions in an urban German population.

Methods

Participating in the present study were 2,187 adults (1,138 females [52.0%]; 1,049 males [48.0%], age: 18–65 years) taken from a sample of 4,000 persons randomly chosen from an urban population. Data on health behaviour like physical activity, tobacco and alcohol consumption were obtained by means of a questionnaire, documentation of anthropometric data, abdominal ultrasound and blood specimens for assessment of chemical parameters.

Results

The overall rate of participation was 62.8%. Of these, 50.3% of the adults were overweight or obese. The proportion of active tobacco smokers stood at 30.1%. Of those surveyed 38.9% did not participate in any physical activity. Less than 2 hours of leisure time physical activity per week was associated with female sex, higher BMI (Body Mass Index), smoking and no alcohol consumption. Participants consumed on average 12 grams of alcohol per day. Total cholesterol was in 62.0% (>5.2 mmol/l) and triglycerides were elevated in 20.5% (≥ 2.3 mmol/l) of subjects studied. Hepatic steatosis was identified in 27.4% of subjects and showed an association with male sex, higher BMI, higher age, higher total blood cholesterol, lower HDL, higher triglycerides and higher ALT.

Conclusion

This random sample of German urban adults was characterised by a high prevalence of overweight and obesity. This and the pattern of alcohol consumption, smoking and physical activity can be considered to put this group at high risk for associated morbidity and underscore the urgent need for preventive measures aimed at reducing the significantly increased health risk.
Knee loading stimulates cortical bone formation in murine femurs
Authors: Zhang Ping , Su Min , Tanaka Shigeo M , Yokota Hiroki
Published: September 2006

Background

Bone alters its architecture and mass in response to the mechanical environment, and thus varying loading modalities have been examined for studying load-driven bone formation. The current study aimed to evaluate the anabolic effects of knee loading on diaphyseal cortical bone in the femur.

Methods

Using a custom-made piezoelectric loader, 0.5-N loads were laterally applied to the left knee of C57/BL/6 mice at 5, 10, 15, and 20 Hz for 3 minutes per day for 3 consecutive days. Animals were sacrificed for examination 13 days after the last loading. The contralateral femur was used as a non-loading control, and the statistical significance of loading effects was evaluated with p < 0.05.

Results

Although diaphyseal strains were measured as small as 12 μstrains, bone histomorphometry clearly demonstrated frequency-dependent enhancement of bone formation. Compared to a non-loading control, bone formation on the periosteal surface was significantly enhanced. The loading at 15 Hz was most effective in elevating the mineralizing surface (1.7 x; p < 0.05), mineral apposition rate (1.4 x; p < 0.001), and bone formation rate (2.4 x; p < 0.01). The loading at 10 Hz elevated the mineralizing surface (1.4 x; p < 0.05), mineral apposition rate (1.3 x; p < 0.01), and bone formation rate (1.8 x; p < 0.05). The cross-sectional cortical area and the cortical thickness in the femoral diaphysis were significantly increased by loading at 10 Hz (both 9%) and 15 Hz (12% and 13%, respectively).

Conclusion

The results support the anabolic effects of knee loading on diaphyseal cortical bone in the femur with small in situ strain, and they extend our knowledge on the interplay between bone and joints. Strengthening the femur contributes to preventing femoral fractures, and the discovery about the described knee loading might provide a novel strategy to strengthen osteoporotic bones. Further analyses are required to understand the biophysical and molecular mechanism behind knee loading.
AS OLD BECOMES NEW: GLOTTALIZATION IN VERMONT
Authors: Roberts Julie
Published: September 2006

Glottalization is a well-researched variable most often noted in Great Britain and Ireland but rarely in North America. The current study examines this phenomenon in a rural region of northwestern Vermont in which the dialect is popularly thought to be dying out. Forty-seven Vermonters, aged 3-80 years, were interviewed and recorded. Glottalized tokens of /t/ were coded perceptually and classified according to position in word and phonological environment. Social factors comprised age and sex. Results revealed that, unlike some vowel features historically associated with the region, glottalization appears to be a robust feature of Vermont speech. Younger speakers, particularly the adolescents, showed the highest rate of glottalization. However, differences in the patterning of the feature in different age groups begs the question of whether the glottalization in the speech of the younger speakers is, in fact, the same feature as that heard in the oldest speakers in the study or a new, less local variant. Finally, the importance of combining accounts of linguistic behavior to allow for better interpretation of data is discussed. In this study, phonetic, historical, and sociocultural information were all utilized in the interpretation of the findings, as none presented a convincing interpretation alone.
Postcolonial Literature and the Magic Radio: The Language of Rushdie'sMidnight's Children
Authors: Gane Gillian
Published: September 2006

Much postcolonial literature depends on unacknowledged processes of translation working like the “radio” in Salman Rushdie's Midnight's Children that magically renders all Indian languages intelligible to the children of midnight. It is surprisingly difficult to determine what languages the characters in Rushdie's novel are actually speaking; though there can be found in the novel several of the strategies Meir Sternberg identifies with translational mimesis (the representation of one language within another), the material substance of English is important in much of its dialogue. Arguably, the English language itself is the magic radio by means of which meaning becomes accessible in Midnight's Children—and Rushdie's own comments reveal ultimately that he evaded the issue of the underlying languages the characters are speaking.
The expression level of frog relaxin mRNA (fRLX), in the testis of Rana esculenta, is influenced by testosterone
Authors: De Rienzo Gianluca , Aniello Francesco , Branno Margherita , Izzo Gaia , Minucci Sergio
Published: September 2006

Frog relaxin (fRLX) belongs to the relaxin/insulin gene family present in the testis of Rana esculenta and is specifically expressed by Leydig cells. Since the expression of fRLX transcript changes during the reproductive cycle and is more abundant when circulating levels of androgens are relatively high, we investigated the effect(s) of testosterone and its antagonist (cyproterone acetate, CPA) on its expression pattern, in the testis of the frog Rana esculenta. Results from in vivoand in vitro experiments demonstrate that testosterone strongly induces a significant increase of fRLX mRNA expression in frog testes and, this effect is counteracted by CPA, supporting the existence of intratesticular (autocrine/paracrine) mechanisms of action. Interestingly, in both the control and testosterone-treated testes, fRLX mRNA expression was markedly decreased 24 h post-treatment, as compared to that measured at 2 h and 8 h post-treatment, suggesting that factor(s), other than testosterone, may act(s) in controlling its expression. In addition, RT-PCR analysis and in situ hybridization performed on frog testis injected with CPA for 15 days, on alternate days, showed a strong decrease of fRLX expression, suggesting that CPA counteracts the effect of testosterone on fRLX expression. Taken together our results strongly indicate that changes in the production, by the Leydig cells, of both testosterone and fRLX may represent a marker for the study of Leydig cell activity in the testis of the frog Rana esculenta.
Dietary acidification enhances phosphorus digestibility but decreases H+/K+-ATPase expression in rainbow trout
Authors: Sugiura Shozo H. , Roy Prabir K. , Ferraris Ronaldo P.
Published: September 2006

Oxynticopeptic cells of fish stomach are thought to secrete less acid than the specialized parietal cells of mammalian stomach. Gastric acidity, however,has not been directly compared between fish and mammals. We therefore fed rainbow trout and rats the same meal, and found that the lowest postprandial pH of trout stomach was 2.7, which was only transiently sustained for 1 h,whereas that of rat stomach was 1.3, which was sustained for 3 h. Postprandial pH of the small intestine was slightly higher in trout (∼8.0) than in rats(∼7.6), but pH of the large intestine was similar (∼8.0). Addition of acids to fish feeds, in an attempt to aid the weak acidity of fish stomach,has been known to improve phosphorus digestibility, but its physiological effect on fish stomach is not known. Exogenous acids did improve phosphorus digestibility but also decreased steady-state mRNA expression of trout H+/K+-ATPase (ATP4A, the proton pump) as well as Na+/bicarbonate cotransporter (NBC), and had no effect on gastrin-like mRNA and somastostatin (SST) mRNA abundance. Gastrin-like mRNA and SST-2 mRNA were equally distributed between corpus and antrum. ATP4A mRNA and NBC mRNA were in the corpus, whereas SST-1 mRNA was in the antrum. Trout gastrin-like EST had modest homology to halibut and pufferfish gastrin,whereas trout ATP4A mRNA had ≥95% amino acid homology with mammalian, Xenopus and flounder ATP4A. Although ATP4A seems highly conserved among vertebrates, gastric acidity is much less in trout than in rats,explaining the low digestibility of bone phosphorus, abundant in fish diets. Dietary acidification does not reduce acidity enough to markedly improve phosphorus digestibility, perhaps because exogenous acids may inhibit endogenous acid production.
Effects of long-term hypoxia on enzymes of carbohydrate metabolism in the Gulf killifish,Fundulus grandis
Authors: Martínez Mery L. , Landry Christie , Boehm Ryan , Manning Steve , Cheek Ann Oliver , Rees Bernard B.
Published: September 2006

The goal of the current study was to generate a comprehensive, multi-tissue perspective of the effects of chronic hypoxic exposure on carbohydrate metabolism in the Gulf killifish Fundulus grandis. Fish were held at approximately 1.3 mg l-1 dissolved oxygen (∼3.6 kPa) for 4 weeks, after which maximal activities were measured for all glycolytic enzymes in four tissues (white skeletal muscle, liver, heart and brain), as well as for enzymes of glycogen metabolism (in muscle and liver) and gluconeogenesis(in liver). The specific activities of enzymes of glycolysis and glycogen metabolism were strongly suppressed by hypoxia in white skeletal muscle, which may reflect decreased energy demand in this tissue during chronic hypoxia. In contrast, several enzyme specific activities were higher in liver tissue after hypoxic exposure, suggesting increased capacity for carbohydrate metabolism. Hypoxic exposure affected fewer enzymes in heart and brain than in skeletal muscle and liver, and the changes were smaller in magnitude, perhaps due to preferential perfusion of heart and brain during hypoxia. The specific activities of some gluconeogenic enzymes increased in liver during long-term hypoxic exposure, which may be coupled to increased protein catabolism in skeletal muscle. These results demonstrate that when intact fish are subjected to prolonged hypoxia, enzyme activities respond in a tissue-specific fashion reflecting the balance of energetic demands, metabolic role and oxygen supply of particular tissues. Furthermore, within glycolysis, the effects of hypoxia varied among enzymes, rather than being uniformly distributed among pathway enzymes.
Feeding and digestion in low salinity in an osmoconforming crab, Cancer gracilis II. Gastric evacuation and motility
Authors: McGaw Iain J.
Published: September 2006

Gastric evacuation and gut contraction rates were followed in the graceful crab Cancer gracilis during exposure to low salinity. Crabs were fed a radio-opaque meal and then exposed to 100% seawater (SW), 80%SW or 60%SW;passage of digesta was followed using a fluoroscope. Exposure to low salinity increased the time for food passage through the gut system. Times for emptying of the foregut, midgut and hindgut varied in a dose-dependent manner. In the lowest salinity, crabs regurgitated food from the foregut after approximately 6 h. This may act as a protective response, clearing the gut and avoiding subsequent increases in metabolism associated with digestion. Contraction rate of the cardiac stomach and gastric mill was sporadic and there was no significant change with salinity. In contrast, contractions of the pyloric region were more constant and rapid. Pyloric contractions decreased at each salinity within 2-4 h after feeding. Contraction rates of the pyloric chamber were significantly lower in 60%SW compared with 100%SW and 80%SW. During a salinity cycle there was also slowing of gut contractions and food passage through the gut system. Pre-treatment levels were only regained slowly when the animals were returned to 100%SW. Cancer gracilis was able to slow digestion during low salinity exposure, which may spare resources for other systems. However, the crabs could not halt digestion completely and may be committed to protein synthesis once intracellular digestion has begun.
Expression of ABCA3 in Developing Lung and Other Tissues
Authors: Stahlman Mildred T. , Besnard Valérie , Wert Susan E. , Weaver Timothy E. , Dingle Sharon , Xu Yan , Zychlin Kara von , Olson Sandra J. , Whitsett Jeffrey A.
Published: September 2006

ABCA3 is a member of the ATP-binding cassette (ABC) family of transport proteins and is required for perinatal respiratory adaptation. Monoclonal and polyclonal antibodies were generated against a recombinant human ABCA3 peptide and used to assess its expression in the developing lung and adult tissues. Immunostaining for ABCA3 was detected at highest levels in type II epithelial cells of the lung but was also noted in other organs including liver, stomach, kidney, adrenal, pancreas, trachea, and brain. In the fetal lung, ABCA3 staining and mRNA increased prior to birth. Like other surfactant protein genes, ABCA3 expression was induced by thyroid transcription factor-1 in vitro. ABCA3 was coexpressed with SP-B and proSP-C in type II epithelial cells. ABCA3 staining was detected surrounding large, intracellular organelles consistent with its association with lamellar bodies. In the human fetal lung, ABCA3 staining was not detected prior to 22-23 weeks of gestation, except in the presence of pulmonary inflammation. ABCA3 was detected in type II epithelial cells of the human lung from 28 weeks of gestation and thereafter. Postnatally, intense ABCA3 staining was observed in hyperplastic epithelial cells relining injured airways in infants with chronic lung disease. Localization and regulation of ABCA3 in the respiratory epithelium is consistent with its proposed role in surfactant homeostasis. The role of ABCA3 in extrapulmonary tissues and organs remains to be elucidated. This manuscript contains online supplemental material at http://www.jhc.org . Please visit this article online to view these materials.
APOBEC3G Expression Is Restricted to Epithelial Cells of the Proximal Convoluted Tubules and Is Not Expressed in the Glomeruli of Macaques
Authors: Hill M. Sarah , Ruiz Autumn , Gomez Lisa M. , Miller Jean-Marie , Berman Nancy E.J. , Stephens Edward B.
Published: September 2006

The Vif protein of human immunodeficiency virus-1 (HIV-1) interacts with members of the APOBEC family of cytidine deaminases. In this study, we isolated RNA from renal cortex as well as from isolated glomeruli and tubulointerstitial fractions from two pigtailed macaques that were exsanguinated and perfused with saline. RT-PCR results indicate that APOBEC3G was detected in the tubule fractions but not in the glomerular fractions. Immunoblot analysis using lysates prepared from these same fractions and a monoclonal antibody to APOBEC3G confirmed the RT-PCR findings. To determine which cell types express APOBEC3G, immunohistochemical studies were performed using this monoclonal antibody on renal cortical sections. Our results clearly show that the glomeruli do not express APOBEC3G but that select tubules within the cortex express APOBEC3G at high levels. To further differentiate the distribution of APOBEC3G expression, serial sections were stained with the lectins Dolichos biflorus agglutinin (DBA) and Phaseolus vulgaris erythroagglutinin (PHA-E), which differentially bind to epithelial cells of the tubules and glomeruli. Our results indicate that APOBEC3G expression was restricted to PHA-E-staining tubules and not DBA-staining tubules, suggesting that APOBEC3G expression was restricted to proximal convoluted tubules. These findings suggest that infection of epithelial cells of proximal renal tubules could suppress Vif-defective HIV-1 replication, whereas infection of cells of the glomeruli, a major target of HIV-associated nephropathy, could act as a reservoir for the replication of Vif-defective HIV-1.
Developmental Biology of the Psammomys obesus Pancreas: Cloning and Expression of the Neurogenin-3 Gene
Authors: Vedtofte Louise , Bödvarsdóttir Thóra B. , Karlsen Allan E. , Heller R. Scott
Published: September 2006

The desert gerbil Psammomys obesus, an established model of type 2 diabetes (T2D), has previously been shown to lack pancreatic and duodenal homeobox gene 1 (Pdx-1) expression. Pdx-1 deficiency leads to pancreas agenesis in both mice and humans. We have therefore further examined the pancreas of P. obesus during embryonic development. Using Pdx-1 antisera raised against evolutionary conserved epitopes, we failed to detect Pdx-1 immunoreactivity at any time points. However, at E14.5, Nkx6.1 immunoreactivity marks the nuclei of all epithelial cells of the ventral and dorsal pancreatic buds and the only endocrine cell types found at this time point are glucagon and PYY. At E18.5 the pancreas is well branched and both glucagon- and ghrelin-positive cells are scattered or found in clusters, whereas insulin-positive cells are not found. At E22.5, the acini of the exocrine pancreas are starting to mature, and amylase and carboxypeptidase A immunoreactivity is found scattered and not in all acini. Ghrelin-, glucagon-, PYY-, gastrin-, somatostatin (SS)-, pancreatic polypeptide (PP)-, and insulin-immunoreactive cells are found scattered or in small groups within or lining the developing ductal epithelium as marked by cytokeratin 19. Using degenerate PCR, the P. obesus Neurogenin-3 (Ngn-3) gene was cloned. Nucleotide and amino acid sequences show high homology with known Ngn-3 sequences. Using specific antiserum, we can observe that Ngn-3-immunoreactive cells are rare at E14.5 but readily detectable at E18.5 and E22.5. In conclusion, despite the lack of detection of Pdx-1, the P. obesus pancreas develops similarly to Muridae species, and the Ngn-3 sequence and expression pattern is highly conserved in P. obesus.
Standardization of Immunohistochemistry for Formalin-fixed, Paraffin-embedded Tissue Sections Based on the Antigen-retrieval Technique: From Experiments to Hypothesis
Authors: Shi Shan-Rong , Liu Cheng , Taylor Clive R.
Published: September 2006

From a practical point of view, one of the most difficult issues in the standardization of IHC for FFPE tissue is the adverse influence of formalin upon antigenicity, as well as the great variation in fixation/processing procedures. Based on previous study, an additional study using four markers demonstrated the potential for obtaining equivalent IHC staining among FFPE tissue sections with periods of formalin fixation ranging from 6 hr to 30 days. On this basis, the following hypothesis is proposed. “The use of optimized AR protocols permits retrieval of specific proteins (antigens) from FFPE tissues to a defined and reproducible degree (expressed as R%), with reference to the amount of protein present in the original fresh/unfixed tissue”. This hypothesis may also be presented mathematically: the protein amount in a fresh cell/tissue, expressed as Pf, produces an IHC signal in fresh tissue of ∫ (Pf). When the identical IHC staining plus AR treatment is applied to a FFPE tissue section, the IHC signal may be represented as ∫ (Pffpe). The degree of retrieval after AR (R%) is calculated as follows: R% = ∫ (Pffpe)/ ∫ (Pf) × 100%. The amount of protein in the FFPE tissue may then be derived as follows: Pffpe = Pf × R%. In a situation where optimized AR is 100% effective, the IHC signal would then be of equal strength in fresh tissue and FFPE tissue, and Pffpe = Pf. Further studies are designed to test the limitations of the proposed hypothesis.
Well Performance With Operating Limits Under Reservoir and Completion Uncertainties
Authors: Wehunt C. D.
Published: September 2006

This paper shows how to evaluate well performance under conditions of reservoir and completion uncertainty while also considering the impact of completion decisions and operating constraints. This topic is important because it can help to reconcile the often large gap between short-term deliverability and reliable and sustainable performance.

Table 1 presents a list of operating constraints, and this paper includes examples regarding the application of some of the constraints. This table also includes consideration for the type of surveillance that is needed to apply the constraints. Discussion within the paper shows that the most relevant types of operating constraints are often not being used and also addresses appropriate operating limits for completions with sand control.

Completion selection and design influence operating constraints. Examples within the paper illustrate methods to determine appropriate operating constraints. The examples also demonstrate the potential advantage of frac-packed completions or long horizontal completions with regard to preventing fines movement and increasing the longevity of both the completion equipment and the productivity.

To aid with probabilistic performance forecasting, the paper includes a tabulation of published skin values including some permeability data.
Control of Inhibitor Squeeze Through Mechanistic Understanding of Inhibitor Chemistry
Authors: Tomson Mason B. , Kan Amy T. , Fu Gongmin
Published: September 2006

Chemical scale inhibitors are commonly used to prevent or inhibit scale formation in production. The most economic treatment of scale inhibitor is normally through chemical squeeze. However, there is little agreement regarding the primary mechanism by which the threshold scale inhibitors are retained in producing oil or gas formations as a result of squeeze procedures. Recent advances in phosphonate/rock interaction research at the Rice U. Brine Chemistry Consortium have significantly improved our knowledge of what controls inhibitor placement in the formation. It is commonly suggested that reservoir type determines how an inhibitor is retained in a formation. Our research suggests that the pill chemistry is also an important determinant for retention of carbonate reservoir. Acidic pills are mostly retained near the wellbore, while more neutralized pills move farther into the formation. Three calcium nitrilomethylenephosphonate (NTMP) solid phases, an amorphous phase, and two crystalline Ca2.5HNTMP phases with pKsp = 22.6 and pKsp = 24.2, are particularly important for inhibitor retention. The relative sizes of these solid phases formed are governed by the pill composition and acidity. These results can be explained by a solution-phase-controlled sequence of reactions. All of this information has been incorporated into a new squeeze-design software program, SqueezeSoftPitzer.
A New OCTG Strength Equation for Collapse Under Combined Loads
Authors: Klever F. J. , Tamano T.
Published: September 2006

Wells are becoming more challenging, and casing designers are faced with increasing design pressures. Deep hydrocarbon targets lead to requirements for the casing to resist collapse under external pressure, while significant internal pressure and axial compression or tension may exist at the same time.

This paper describes the development, and its evaluation, of a new collapse-strength equation for oil-country tubular goods (OCTG). It is based on a generalization of a model previously proposed by Tamano et al. (1983). The new model is evaluated through comparisons with both finite-element analyses(FEAs) and test data. It is more accurate in dealing with combined internal pressure, external pressure, and axial load than, for example, the model currently provided in American Petroleum Inst. (API) Bull. 5C3 (1994).

The joint API/Intl. Standardization Organization (ISO) subcommittee (SC)5 Work Group (WG) 2B tasked with modernizing the Bull. 5C3 property equations has evaluated a number of collapse models available in the literature on their performance against several collapse databases. As a result, the model presented here is recommended for developing design collapse strengths in the new ISO TR 10400 standard (2006).
Meeting the Challenges in Completion Liner Design and Execution for Two High-Rate Acid-Gas Injection Wells
Authors: Benge Glen , Dew E. G.
Published: September 2006

Two high-rate acid-gas injection wells were drilled in the LaBarge area of Wyoming. These wells were designed for injection of up to 65 million scf/D of a mixture of 65% H2S and 35% CO2. The primary engineering challenges in well design, casing selection, and cementing of the injection strings, along with the related operational challenges for both wells, are discussed. Key drivers influencing zonal isolation, salt-zone loading, casing, and centralizer selection are presented.

Casing selection was influenced by corrosive gas composition, high injection rates, and the potential for salt-zone loading. The use of SM–2550 tubulars, heavy wall casing for the salt loading, handling requirements, and centralizer selection are discussed.

The primary driver in cement design was resistance to CO2, because past work has shown little H2S interaction with cement under these well conditions. A discussion of the development of a high-alumina cement system with low fluid loss to address CO2 resistance and long liner length is coupled with the quality-control steps taken from the time of manufacture of the specialty cement to the final placement in the well.

Also described is the development of an alternative portland cement system in which sized particles are included to dilute the cement and reduce total system permeability.

The unique engineering solutions resulted in operational challenges with casing running, cementing materials, and equipment. A description of the location problems and the steps taken to resolve the issues is included.
Swelling of Coal in Response to CO2 Sequestration for ECBM and Its Effect on Fracture Permeability
Authors: Mazumder Saikat , Karnik Amit , Wolf Karl Heinz
Published: September 2006

The "swelling" of coal by a penetrant refers to an increase in the volume occupied by the coal as a result of the viscoelastic relaxation of its highly crosslinked macromolecular structure. Projects relating to CO2 sequestration in coal seams suffer a serious setback in terms of injectivity loss resulting from the swelling of coal. Volumetric swelling associated with CO2 sorption on coal has a significant influence on the fracture porosity and permeability of the coal. Two coal samples differing in rank were used for volumetric strain measurements. With CO2, the high-rank Selar Cornish coal showed a maximum volumetric strain of 1.48% corresponding to an average pore pressure of 13 MPa. A matrix swelling coefficient (Cm) of 1.77×10−4 MPa−1 was calculated for this Selar Cornish coal. The low-rank Warndt Luisenthal coal exhibited higher strain of 1.6%, and a matrix swelling coefficient (Cm) of 8.98×10−5 MPa−1 was calculated. The rank dependence of swelling holds true in this set of experiments. Repeat volumetric strain measurement on the same Warndt Luisenthal coal core shows higher volumetric strain values for all pressure steps. A volumetric strain of 1.9% corresponding to a mean pore pressure of 14 MPa was measured. This confirms the process of sequential swelling.

A unique feature of this work is that real-time permeability measurements were done under unconstrained conditions. Permeabilities were measured, reducing the pore pressure from 16 to 1 MPa at constant flow rate. Although measured permeability increased with increasing pore pressure under unconstrained swelling, in-situ permeability will actually decrease because of fracture closure in a constrained coal. To validate the permeability swelling relationship, both permeability measurements under unconstrained conditions and volumetric strain measurements were used.