Preparation of palm (Elaeis oleifera) pressed fibre cellulose nanocrystals via cation exchange resin: characterisation and evaluation as Pickering emulsifier

BACKGROUND

Palm pressed fibre (PPF) is a cellulose-rich biomass residue produced during palm oil extraction. Its high cellulose content allows the isolation of cellulose nanocrystal (CNC). CNC has attracted scientific interest due to its biodegradability, biocompatibility and low cost. The present study isolated CNC from PPF using a cation exchange resin, which is an environmentally friendly and less harsh hydrolysis method than conventional mineral acid hydrolysis. Isolated CNC was used to stabilise an oil-in-water emulsion and the emulsion stability was evaluated in terms of droplet size, morphology and physical stability.

RESULTS

PPF was subjected to alkali and bleach treatment prior to hydrolysis, which successfully removed 54% and 75% of non-cellulosic components (hemicellulose and lignin, respectively). Hydrolysis conditions of 5 h, 15:1 (w/w) resin-to-pulp ratio and 50 °C produced CNC particles of 50-100 nm in length. CNC had a crystallinity index of 42% and appeared rod-like morphologically. CNC-stabilised emulsion had better stability when used in combination with soy lecithin (SL), a well-established, commonly used food stabiliser. Emulsion stabilised by the binary mixture of CNC and SL had droplet size, morphology and physical stability comparable to those of emulsion stabilised using SL.

CONCLUSIONS

CNC was successfully isolated from PPF through a cation exchange resin. This offers an alternative usage for the underutilised PPF to be converted into value-added products. Isolated CNC was also found to have promising potential in the stabilisation of Pickering emulsions. These results provide useful information indicating CNC as a natural and sustainable stabiliser for food, cosmeceutical and pharmaceutical applications. © 2021 Society of Chemical Industry.

The effects of traffic light labelling versus cartoon labelling on food and beverage purchases in a children's hospital setting

This study's purpose was to examine changes in healthy and unhealthy items purchased following the implementation of traffic light and cartoon labelling in a small retail food venue (Café Bay) in a children's hospital in eastern North Carolina. Between October 2015 and March 2016, daily food and beverage sales from Café Bay were obtained during baseline, traffic light labelling, a washout period, cartoon labelling (on healthy foods only) and a final washout period. Pearson chi-squared tests and multiple linear regressions were used to examine effects of labelling strategies, controlling for the holidays. In unadjusted analyses, traffic light labelling was associated with significant decreases in purchases of unhealthy items purchased, while cartoon labelling was associated with increases in unhealthy items purchased. In adjusted linear regression analysis, traffic light labelling was associated with fewer unhealthy purchases and thus may have potential to decrease the amount of unhealthy items purchased in a children's hospital food retail venue.

Ten-year beverage intake trends among US preschool children: rapid declines between 2003 and 2010 but stagnancy in recent years

BACKGROUND

It has been previously reported that total energy intake among US preschool children (ages 2-5 years) decreased between 2003-2004 and 2009-2010. However, little is known about how intakes of beverages among US preschoolers (ages 2-5 years) changed from 2003-2004 to 2011-2012.

OBJECTIVES

This paper examines changes in intakes of key beverages during this period, as well as how eating location (at home or away from home) and source (store vs. others) may have contributed to these changes.

METHODS

Cross-sectional day one dietary data among children ages 2-5 years from the National Health and Nutrition Examination Survey 2003-2004, 2005-2006, 2007-2008, 2009-2010 and 2011-2012 were used. Survey-weighted mean intakes by survey year, eating location and source were computed for total sugar-sweetened beverages (SSBs), milks, 100% juice, low/no-calorie beverages, 10 key beverages, total beverages and total foods. Means were compared using two-tailed z-tests with Bonferroni corrections (α < 0.05).

RESULTS

Between 2003-2004 and 2011-2012, among 2-5 year olds, total caloric intake fell by 132 kcal d(-1) , with intakes of beverages falling by 55 kcal d(-1) . Decreases in intakes of total SSBs (-57 kcal d(-1) ), fruit-flavoured or juice drinks containing <100% juice (juice drinks) (-37 kcal d(-1) ), caloric soft drinks (-13 kcal d(-1) ) and >1% fat, low-sugar milk (-42 kcal d(-1) ) were among the major changes. By eating location, total beverage intake at home fell by 73 kcal d(-1) . By source, total beverage intake from stores fell by 106 kcal d(-1) . Changes in intakes occurred primarily between 2003-2004 and 2009-2010, as there were no significant differences in beverage intakes between 2009-2010 and 2011-2012. Intakes of total calories (+49 kcal d(-1) ) and calories from foods (+53 kcal d(-1) ) trended upward between 2009-2010 and 2011-2012, but changes were not significant.

CONCLUSIONS

These findings suggest improvements in the diets of preschoolers between 2003-2004 and 2009-2010, of which stores were a major contributor.

Corticosteroid adulteration in proprietary Chinese medicines: a recurring problem

OBJECTIVES

To investigate adulteration of proprietary Chinese medicines with corticosteroids in Hong Kong.

DESIGN

Case series with cross-sectional analysis.

SETTING

A tertiary clinical toxicology laboratory in Hong Kong.

PATIENTS

All patients using proprietary Chinese medicines adulterated with corticosteroids and referred to the authors' centre from 1 January 2008 to 31 December 2012.

MAIN OUTCOME MEASURES

Patients' demographic data, clinical presentation, medical history, drug history, laboratory investigations, and analytical findings of the proprietary Chinese medicines were analysed.

RESULTS

The records of 61 patients who consumed corticosteroid-adulterated proprietary Chinese medicines were reviewed. The most common corticosteroid implicated was dexamethasone. Co-adulterants such as non-steroidal anti-inflammatory drugs and histamine H1-receptor antagonists were detected in the proprietary Chinese medicine specimens. Among the patients, seven (11.5%) required intensive care, two (3.3%) died within 30 days of presentation, and 38 (62.3%) had one or more complications that were potentially attributable to exogenous corticosteroids. Of 22 (36.1%) patients who had provocative adrenal function testing performed, 17 (77.3% of those tested) had adrenal insufficiency.

CONCLUSION

The present case series is the largest series of patients taking proprietary Chinese medicines adulterated with corticosteroids. Patients taking these illicit products are at risk of severe adverse effects, including potentially fatal complications. Adrenal insufficiency was very common in this series of patients. Assessment of adrenal function in these patients, however, has been inadequate and routine rather than discretionary testing of adrenal function is indicated in this group of patients. The continuing emergence of proprietary Chinese medicines adulterated with western medication indicates a persistent threat to public health.

The physical activity transition among adults in China: 1991-2011

Previous studies have linked work, home production, travel activities and inactivity with weight and health outcomes. However, these focused on average physical activity (PA) over time rather than changes in PA and associated sociodemographic and economic factors and urbanicity. Using the 1991-2011 China Health and Nutrition Survey data, we estimated the metabolic equivalent of task hours per week for individuals in occupational, domestic, travel and active leisure domains and sedentary hours per week. We present the distributions among adult men and women (aged 18-60), and use quantile regression models to explore factors associated with these trends. Trend analyses on the distribution of PA show declines along the whole distribution of occupational PA for men and women and domestic PA for women in China. These patterns remain consistent after adjusting for individual- and household-level factors. Controlling for urbanicity mitigated the decrease in occupational PA, particularly for men, but not the decrease in domestic PA. Given China's rapid urbanization and its association with occupational PA declines and the strong time trend in domestic PA, there is a need to invest in interventions and policies that promote PA during leisure and travel times.

Ultra-processed products are becoming dominant in the global food system

The relationship between the global food system and the worldwide rapid increase of obesity and related diseases is not yet well understood. A reason is that the full impact of industrialized food processing on dietary patterns, including the environments of eating and drinking, remains overlooked and underestimated. Many forms of food processing are beneficial. But what is identified and defined here as ultra-processing, a type of process that has become increasingly dominant, at first in high-income countries, and now in middle-income countries, creates attractive, hyper-palatable, cheap, ready-to-consume food products that are characteristically energy-dense, fatty, sugary or salty and generally obesogenic. In this study, the scale of change in purchase and sales of ultra-processed products is examined and the context and implications are discussed. Data come from 79 high- and middle-income countries, with special attention to Canada and Brazil. Results show that ultra-processed products dominate the food supplies of high-income countries, and that their consumption is now rapidly increasing in middle-income countries. It is proposed here that the main driving force now shaping the global food system is transnational food manufacturing, retailing and fast food service corporations whose businesses are based on very profitable, heavily promoted ultra-processed products, many in snack form.

Complexities and opportunities in monitoring and evaluating US and global changes by the food industry

In developed nations and increasingly in the rest of the world, a large proportion of people's diets comes from manufactured food sources and food not produced at home. These types of products are constantly changing and have significant nutrition and health implications for the world's population. However, researchers, public health workers and policy makers face major complexities in understanding what these changes are and their relationships to diet and health outcomes. This paper will describe some of the complexities faced in monitoring and evaluating the nutritional composition of food products and what it means for population health. Importantly, no existing food composition database is able to keep up with the continuous reformulation and introductions and removals of packaged foods and food services. The paper will also discuss opportunities to improve and update the monitoring and evaluation of changes made by each of these key sectors of the modern food supply and how these changes can influence the nutrients purchased or consumed across the globe. The focus will be on the United States with some examples from other developed nations and a discussion of implications for low- and middle-income countries.

Time use and physical activity: a shift away from movement across the globe

Technology linked with reduced physical activity (PA) in occupational work, home/domestic work, and travel and increased sedentary activities, especially television viewing, dominates the globe. Using detailed historical data on time allocation, occupational distributions, energy expenditures data by activity, and time-varying measures of metabolic equivalents of task (MET) for activities when available, we measure historical and current MET by four major PA domains (occupation, home production, travel and active leisure) and sedentary time among adults (>18 years). Trends by domain for the United States (1965-2009), the United Kingdom (1961-2005), Brazil (2002-2007), China (1991-2009) and India (2000-2005) are presented. We also project changes in energy expenditure by domain and sedentary time (excluding sleep and personal care) to 2020 and 2030 for each of these countries. The use of previously unexplored detailed time allocation and energy expenditures and other datasets represents a useful addition to our ability to document activity and inactivity globally, but highlights the need for concerted efforts to monitor PA in a consistent manner globally, increase global PA and decrease sedentary behavior. Given the potential impact on weight gain and other cardiometabolic health risks, the differential declines in MET of activity and increases in sedentary time across the globe represent a major threat to global health.

Drinking to our health: can beverage companies cut calories while maintaining profits?

Carbonated soft drinks and other beverages make up an increasing percentage of energy intake, and there are rising public health concerns about the links between consumption of sugar-sweetened beverages and weight gain, obesity, and other cardiometabolic problems. In response, the food and beverage industry claims to be reformulating products, reducing package or portion sizes and introducing healthier options. Comparative analysis on various changes and their potential effects on public health are needed. We conduct a case study using the two largest and most influential producers of sweetened beverages, The Coca-Cola Company and PepsiCo Inc., who together control 34% of the global soft drink market, examining their product portfolios globally and in three critical markets (the United States, Brazil and China) from 2000 to 2010. On a global basis, total revenues and energy per capita sold increased, yet the average energy density (kJ 100 mL(-1) ) sold declined slightly, suggesting a shift to lower-calorie products. In the United States, both total energy per capita and average energy density of beverages sold decreased, while the opposite was true in the developing markets of Brazil and China, with total per capita energy increasing greatly in China and, to a lesser extent, in Brazil.

Arthroscopic debridement of intercarpal ligament and triangular fibrocartilage complex tears

INTRODUCTION

Wrist arthroscopy has evolved since its inception to become an essential diagnostic and therapeutic tool for the management of various wrist disorders. Our study aimed to examine the outcomes of arthroscopic debridement in the treatment of scapholunate (SL), lunotriquetral (LT) and triangular fibrocartilage complex (TFCC) tears.

METHODS

We conducted a retrospective review of 68 consecutive wrist arthroscopies performed at our institution between January 2000 and July 2005. All the patients complained of wrist pain, which often interfered with their daily activities, work or sports. A standard arthroscopic technique was employed in all. Any intercarpal ligament or TFCC tears found were debrided.

RESULTS

There were 42 patients with TFCC tears, 58 with SL tears and 49 with LT tears. At a mean follow-up time of 16.6 months, 85.3% of the patients reported an improvement in symptoms and 27.9% had improved range of motion. Grip strength improved by 11.8%. All except two patients returned to their original activities. Outcome following arthroscopic debridement was determined using the Mayo Modified Wrist Score. Based on the postoperative wrist scores of 47 patients, 24 were rated excellent, 17 good, four fair and two poor. By comparing the pre- and postoperative wrist scores of 31 patients, we were able to demonstrate significant improvement in patients who underwent wrist arthroscopies.

CONCLUSION

Our study demonstrated that there is a definite role for arthroscopic debridement in the management of SL, LT and TFCC tears.

The prevalence and trends of overweight, obesity and nutrition-related non-communicable diseases in the Arabian Gulf States

This paper reviews studies on the prevalence of overweight, obesity and related nutrition-related non-communicable diseases in Bahrain, Kuwait, Qatar, Oman, Saudi Arabia and the UAE. Obesity is common among women; while men have an equal or higher overweight prevalence. Among adults, overweight plus obesity rates are especially high in Kuwait, Qatar and Saudi Arabia, and especially among 30-60 year olds (70-85% among men; 75-88% among women), with lower levels among younger and elderly adults. The rate of increase in obesity was pronounced in Saudi Arabia and Kuwait. Prevalence of obesity is high among Kuwaiti and Saudi pre-schoolers (8-9%), while adolescent overweight and obesity are among the highest in the world, with Kuwait having the worst estimates (40-46%); however, comparison of child data is difficult because of differing standards. Among nutrition-related non-communicable diseases, hypertension and diabetes levels are very high and increase with age, with the UAE performing the worst because of a rapid rate of increase between 1995 and 2000. Additional monitoring of the prevalence of metabolic syndrome and cancers is necessary. Nationally representative longitudinal surveys with individual, household and community-level information are needed to determine the importance of various factors that contribute to these troubling trends.

Identification of regions of the P2X(7) receptor that contribute to human and rat species differences in antagonist effects

BACKGROUND AND PURPOSE

Several P2X(7) receptor antagonists are allosteric inhibitors and exhibit species difference in potency. Furthermore, N(2)-(3,4-difluorophenyl)-N(1)-(2-methyl-5-(1-piperazinylmethyl)phenyl)glycinamide dihydrochloride (GW791343) exhibits negative allosteric effects at the human P2X(7) receptor but is a positive allosteric modulator of the rat P2X(7) receptor. In this study we have identified several regions of the P2X(7) receptor that contribute to the species differences in antagonist effects.

EXPERIMENTAL APPROACH

Chimeric human-rat P2X(7) receptors were constructed with regions of the rat receptor being inserted into the human receptor. Antagonist effects at these receptors were measured in ethidium accumulation and radioligand binding studies.

KEY RESULTS

Exchanging regions of the P2X(7) receptor close to transmembrane domain 1 modified the effects of KN62, 4-(4-fluorophenyl)-2-(4-methylsulphinylphenyl)-5-(4-pyridyl)1H-imidazole (SB203580) and GW791343. Further studies, in which single amino acids were exchanged, identified amino acid 95 as being primarily responsible for the differential allosteric effects of GW791343 and, to varying degrees, the species differences in potency of SB203580 and KN62. The species selectivity of pyridoxalphosphate-6-azophenyl-2',4'-disulphonic acid was affected by multiple regions of the receptor, with potency being particularly affected by the amino acid 126 but not by amino acid 95. A further region of the rat receptor (amino acids 154-183) was identified that, when inserted into the corresponding position in the human receptor, increased ATP potency 10-fold.

CONCLUSIONS

This study has identified several key residues responsible for the species differences in antagonist effects at the P2X(7) receptor and also identified a further region of the P2X(7) receptor that can significantly affect agonist potency at the P2X(7) receptor.

Factitious thyrotoxicosis and herbal dietary supplement for weight reduction

This article describes three patients who developed factitious thyrotoxicosis, as well as other adverse effects, after taking herbal dietary supplements for weight reduction. All products were found to contain undeclared animal thyroid tissue and western pharmaceuticals causing the adverse effects. Adulteration is concealed addition of undeclared drugs, or other substances with therapeutic effects, to a health product. Consumption of such products, and the concealed components unwittingly, is obviously dangerous. Multiple adulterants in one product are often seen. Untoward adverse effect or drug interaction could occur. Overdose subsequent to poor standardization of the adulterants is another concern. Health care professionals must therefore be aware of the potential dangers posed by adulterated dietary supplements.

Adulteration of over-the-counter slimming products with pharmaceutical analogue--an emerging threat

OBJECTIVES

To review pharmaceutical analogue adulteration of non-prescription slimming products.

DESIGN

Retrospective study.

SETTING

Tertiary referral centre for toxicology analysis, Hong Kong.

PATIENTS

All patients known to have been hospitalised after taking slimming products adulterated with pharmaceutical analogues from September 2004 to December 2006.

MAIN OUTCOME MEASURES

Age, reasons for hospital admission, major biochemical findings, and toxicology analysis results of the offending slimming products.

RESULTS

N-nitrosofenfluramine, an analogue of fenfluramine with hepatotoxic effect, was found in two slimming products. Three patients were hospitalised after taking these slimming products, one of whom developed liver failure treated by liver transplantation. Another slimming product was found to contain N-desmethyl-sibutramine, an analogue of sibutramine. A patient with an unremarkable medical history developed acute psychosis after taking the latter product for 1 week.

CONCLUSIONS

Analogues, created by modifying the chemical structures of pharmaceuticals, are used as adulterants in non-prescription slimming products, in an attempt to evade regulatory inspection. The imperceptible use of these analogues is very dangerous because they have not been tested formally for efficacy and safety. In view of the potential harm to the public, more effective and proactive measures are required to guard against the illicit use of pharmaceutical analogues. There is also a need for increased awareness among the public and the medical professionals about this emerging threat.

How state counter-industry campaigns help prime perceptions of tobacco industry practices to promote reductions in youth smoking

OBJECTIVE

This study assessed the impact of state media campaigns that prominently feature counter-industry messages on youth cigarette smoking, beyond the effects of price, secular trends, tobacco control efforts, and the national truth campaign.

METHODS

Rates of youth smoking were compared in three groups of states: (1) those with long funded counter-industry campaigns (California, Florida, and Massachusetts); (2) states with more recently funded counter-industry media campaigns (Indiana, Minnesota, Mississippi, and New Jersey); and (3) other states. An analysis was performed for a series of national telephone surveys of 12-17 year olds between 1999 and 2002, controlling for differences in demographic background, the price of cigarettes, and exposure to the national truth campaign.

RESULTS

Between 1999 and 2002, rates of current smoking and established smoking decreased significantly faster in states with established or more newly funded counter-industry campaigns than in other states. State counter-industry campaigns appear to prime, or make more salient, negative perceptions about tobacco industry practices.

CONCLUSION

Results highlight the value of continued state counter-industry campaigns.

Analysis of phosphorus removal and anaerobic selector performance in a full-scale activated sludge process in Singapore

This paper analyses the performance of the anaerobic selector (A/O process) in a full-scale activated sludge process receiving mostly industrial sewage discharge (> 60%) in Singapore. In addition to the sludge settleability, enhanced biological phosphorus removal (EBPR) was studied. The sludge volume index (SVI) reduced from 200 to 80 ml g(-1) and foaming was suppressed significantly, indicating the effectiveness of the anaerobic selector in improving sludge settleability. The phosphorus removal efficiency was 66%, and 7.5 mg HAc-COD was consumed per mg PO4(3-) -P removed. In the anaerobic compartment, 31% of the SCOD and 73% of the acetic acid in the settled sewage were removed with PO4(3-) -P release of 14.1 mg PO4(3-)-P l(-1). The linear correlation between PO4(3-) -P release in the anaerobic compartment and PO4(3-) -P uptake in the aerobic compartment indicates that there is about 0.8 mg PO4(3-) -P release in the anaerobic compartment per mg PO34(3-) -P uptake in the aerobic compartment. The fates of volatile fatty acids (VFAs) and its short chain acids (SCAs) in the process were studied and discussed.

On the short carbonyl bond in bis[mu-1,2-benzisothiazol-3(2H)-one 1,1-dioxido-kappa2N:O]bis[[1,2-benzisothiazol-3(2H)-one 1,1-dioxido-kappaN]bis(imidazole)copper(II)]

The short carbonyl bond in the title compound, [Cu(2)(C(7)H(4)NO(3)S)(4)(C(3)H(4)N(2))(4)] [Liu, Huang, Li & Lin (1991). Acta Cryst. C47, 41-43], is an artifact of disorder in the isothiazol-3(2H)-one 1,1-dioxide part of the 1,2-benzisothiazol-3(2H)-one entity. In the present redetermination, all bond dimensions in the centrosymmetric dinuclear molecule are normal. The five-coordinate Cu atom shows trigonal-bipyramidal coordination. Hydrogen bonds from the imidazole donor ligand link adjacent molecules into a two-dimensional layer structure.

SPARC (secreted protein acidic and rich in cysteine) induces apoptosis in ovarian cancer cells

Secreted protein acidic and rich in cysteine (SPARC) is an extracellular Ca(2+)-binding matricellular glycoprotein that associates with cell populations undergoing migration, morphogenesis, and differentiation. Studies on endothelial cells have established that its principal functions in vitro are counteradhesion and antiproliferation. The mechanism(s) underlying these antitumor effects is unknown. In this study, we showed that SPARC expression in ovarian cancer cells is inversely correlated with the degree of malignancy. The immunohistochemical data presented here confirmed the importance of diminished SPARC expression in ovarian cancer development. Treating human ovarian surface epithelial cells and ovarian cancer cells with SPARC revealed that as SPARC inhibits the proliferation of both normal and cancer cells, it induces apoptosis only in cancer cells. This observation indicates that down-regulation of SPARC is essential for ovarian carcinogenesis as cancer cells become sensitized to the apoptotic activity of SPARC during malignant transformation. We also showed here the first direct evidence that putative SPARC receptors are present on ovarian epithelial cells. Their levels are higher in human ovarian surface epithelial cells than cancer cells. Binding of SPARC to its receptor is likely to trigger tissue-specific signaling pathways that mediate its tumor suppressing functions. Decrease in ligand-receptor interaction by the down-regulation of SPARC and/or its receptor is essential for ovarian carcinogenesis.

Toward designed assembly of microporous coordination networks constructed from silver(I)-hexamethylenetetramine layers

Eight interesting microporous networks based on 2-D [Ag(mu(3)-hmt)] (hmt = hexamethylenetetramine) layers were obtained via rational synthetic strategies. Out of these products isolated and structurally characterized, six present a metal-to-hmt molar ratio of 1:1 and contain 2-D coordination layers assembled by 2-D Ag(I)-hmt networks with aromatic monocarboxylates, which are [Ag(mu(3)-hmt)(p-nba)].2.5H(2)O (1), [Ag(mu(3)-hmt)(m-nba)].2.5H(2)O (2), [Ag(mu(3)-hmt)(dnba)] (3), [Ag(mu(3)-hmt)(alpha-hna)](EtOH) (4), [Ag(mu(3)-hmt)(beta-hna)](EtOH) (5), and [Ag(mu(3)-hmt)(noa)](H(2)O)(EtOH) (6) (p-nba = 4-nitrobenzoate, m-nba = 3-nitrobenzoate, dnba = 3,5-dinitrobenzoate, alpha-hna = 1-hydroxy-2-naphthate, beta-hna = 3-hydroxy-2-naphthate, and noa = 2-naphthoxyacetate), and two present a metal-to-hmt molar ratio of 2:1 and contain 3-D microporous networks constructed from the 2-D Ag-hmt layers and linear dicarboxylates as molecular pillars, which are [Ag(2)(mu(3)-hmt)(2)(fa)].4H(2)O (7) and [Ag(2)(mu(3)-hmt)(2)(adp)].8H(2)O (8) (fa = fumarate and adp = adipate). The result shows that the pore sizes may be tuned with different carboxylates. Gas adsorption measurements were performed to confirm the microporosity of these coordination open frameworks.

Experimental and theoretical vibrational study of bis(N,N-dimethylthiocarbamoylthio)acetic acid

Harmonic vibrational analysis at HF/3-21G level is performed on the ab initio optimized molecular structure of bis(N,N-dimethylthiocarbamoylthio)acetic acid, and the outcome used in assigning the infrared spectrum of the acid. The calculated spectrum compares well with the experimental solid-state FT IR spectrum recorded at 298 and at 77 K.

Bis(dicyclohexylammonium 3-thienylacetate)

The triclinic cell of the title compound contains 2C(12)H(24)N(+) x 2C(6)H(5)O(2)S(-) ion pairs that are linked by four hydrogen bonds [N...O = 2.728 (3) and 2.758 (3) A] across a centre of inversion.

N-Propionyl-1,2-benzisoselenazol-3(2H)-one

The title compound, C(10)H(9)NO(2)Se, crystallizes as flat molecules linked by selenium-oxygen interactions [Se.O = 3.189 (4) A] into a linear chain along the a axis of the triclinic cell. The bond dimensions that are derived from ab initio geometry optimization calculations are similar to those determined from the diffraction measurements.

Direct amplification of Entamoeba histolytica DNA from amoebic liver abscess pus using polymerase chain reaction

An important and serious complication of intestinal infection with Entamoeba histolytica is the involvement of the liver (hepatic amoebiasis). Hepatic amoebiasis is usually diagnosed by the clinical picture (pain in the right upper quadrant and fever), ultrasound examination and positive serology. However, none of these tests are definitive and the picture overlaps with pyogenic liver abscess caused by bacteria. It is for this reason that the feasibility of using polymerase chain reaction (PCR) for the detection of E. histolytica DNA in liver abscess pus was investigated. A comparative study was done to verify the sensitivity of ten pairs of primers specific for detecting E. histolytica in stools. Samples of liver abscess pus from 22 serology-positive patients were collected under ultrasound guidance; and these were used directly in PCR assays without any prior pre-treatment of the samples. Of the ten pairs of previously published primers tested, two pairs of primers (PI + P2 and P11 + P12) were found to give 100% sensitivity. Based on these results, we recommend that PCR assay can be successfully used to confirm the diagnosis of amoebic liver abscess with the primers identified.

Generalized low areal and volumetric bone mineral density in adolescent idiopathic scoliosis

Adolescent idiopathic scoliosis (AIS) may be associated with generalized low bone mineral status. The bone mineral density (BMD) of 75 girls of 12-14 years of age and diagnosed as having AIS were compared with 94 age-matched female control subjects. Areal BMD (aBMD) of the lumbar spine (L2-L4) and the bilateral proximal femur were measured using-energy X-ray absorptiometry (DEXA), and volumetric BMD (vBMD) of the nondominant distal radius and bilateral distal tibias was measured with peripheral quantitative computer tomography (pQCT). Relevant anthropometric parameters and the severity of the spinal deformity (Cobb's angle) also were evaluated and correlated with the BMD measurements. Results revealed the presence of a generalized lower bone mineral status in AIS patients. Detailed analysis showed that the aBMD and vBMD measured at the bilateral lower extremities were significantly lower in AIS patients when compared with the same in the normal controls. The most significant effect was seen in the trabecular BMD (tBMD) of the distal tibias. Of all the AIS girls, 38% of the aBMD and 36% of the vBMD were below -1 SD of the normal. BMD was found to correlate better with "years since menarche" (YSM) than with chronological age. When the BMD was evaluated for the 3 YSM groups, aBMD of the proximal femur and tBMD of distal tibias were found to be significantly lower in the AIS patients. Neither the aBMD nor the vBMD of AIS patients was found to be associated with the severity of spinal deformity. In addition, anthropometric measurements showed significantly longer arm span and lower extremities in the AIS girls. We concluded that the AIS girls had generalized lower aBMDs and vBMDs.

Linear chains in polymeric dicyclohexylammonium tributyl(4-oxo-4H-pyran-2,6-dicarboxylato)stannate and methylphenylammonium tributyl(pyridine-2,6-dicarboxylato)stannate containing trigonal bipyramidal tin

catena-Poly[dicyclohexylammonium [tributyltin-mu-(4-oxo-4H-pyran-2,6-dicarboxylato-O(2):O( 6))]], (C(12)H(24)N)[Sn(C(7)H(2)O(6))(C(4)H(9))(3)], consists of 4-oxo-4H-pyran-2,6-dicarboxylato groups that axially link adjacent tributyltin units into a linear polyanionic chain. The ammonium counter-ions surround the chain, and each cation forms a pair of hydrogen bonds to the double-bond carbonyl O atoms of the same dianionic group. The chain propagates in a zigzag manner along the c axis of the monoclinic cell. In catena-poly[methyl(phenyl)ammonium [tributyltin-mu-(pyridine-2,6-dicarboxylato-O(2):O(6))]], (C(7)H(10)N)[Sn(C(7)H(3)NO(4))(C(4)H(9))(3)], the pyridine-2, 6-dicarboxylato groups also link the tributyltin groups into a chain, but the hydrogen-bonded chain propagates linearly on the ac face of the monoclinic cell.

Expression of topoisomerase IIIalpha in normal and neoplastic tissues determined by immunohistochemistry using a novel monoclonal antibody

Topoisomerases are nuclear enzymes that modulate the topological structure of DNA in order to facilitate cellular events such as replication and transcription. These enzymes are also the cellular targets of certain classes of chemotherapeutic agents termed topoisomerase poisons. A new human topoisomerase isoform, IIIa, was discovered in 1996, which is thought to have roles in genome stability and possibly chromosome separation during mitosis. It is possible that novel or existing anti-topoisomerase agents target topoisomerase IIIa, suggesting that this enzyme may have potential as a prognostic marker and chemotherapeutic target. In order to study expression patterns of topoisomerase IIIa we have produced a novel monoclonal antibody to human topoisomerase IIIa (TOPO3a-1A4), and used it to assess topoisomerase IIIa expression in a wide range of normal and neoplastic tissues. We have found that topoisomerase IIIa is expressed in a wide range of tissue types, with especially high concentrations in endothelial cells and stromal fibroblasts. No general relationship was observed between expression of topoisomerase IIIa and proliferation. Expression in neoplastic tissues often paralleled their normal counterparts, although certain tumours showed either increased (e.g. colonic adenoma) or reduced (e.g. gastric carcinoma, small cell carcinoma of bronchus) expression. If topoisomerase IIIa is found to be a target for chemotherapeutic agents, clinical response in different tumour types may be related to topoisomerase IIIa expression, which may be assessed using TOPO3a-1A4.

Analysis of p73 in human borderline and invasive ovarian tumor

p73 is a novel gene that has high sequence homology and similar gene structure to the tumor suppressor gene p53. We analysed p73 in seven ovarian carcinoma cell lines and a total of 63 human borderline and invasive ovarian tumor samples. Loss of heterozygosity at this locus was observed in 50% of invasive tumors but in none of the borderline tumors. Biallelic expression of the gene was observed in the heterozygous tumor tissues. Direct sequencing and single-strand conformation polymorphism analyses of the p73 cDNA sequence homologous to the highly mutatable region of p53 did not reveal any mutations. When compared to the primary cultures of normal human ovarian surface epithelial cells and immortalized cell lines, four of the seven ovarian carcinoma cell lines, 71% of the invasive tumors, and 92% of the borderline tumor tissues express elevated levels of p73 transcript. Except for the OVCA3 cell line, Western blot analysis of the nuclear extracts prepared from the cell lines showed concordant levels of p73 protein. Our analysis also demonstrated the expression of a spliced variant of p73 transcript with the omission of exon 2 solely in the cancer cell lines and invasive tumor tissues. This exon 2-spliced transcript would give rise to a truncated p73 protein without the N-terminal transactivation domain. In reminiscence of the dominant negative phenotype of the N-terminal truncated variants of another p53-related gene, p63, the expression of the truncated p73 variant form in ovarian tumors may play an important role in the pathogenesis of ovarian cancer.

ras gene activation and infrequent mutation in papillary serous carcinoma of the peritoneum

OBJECTIVE

The ras genes are a well-studied family of proto-oncogenes whose involvement in many cancers has been delineated. However, K-ras mutations have not previously been examined in papillary serous carcinoma of the peritoneum (PSCP), a tumor which resembles serous epithelial ovarian carcinoma (SEOC) both in histology and epidemiology. In this study we examine the role of the K-ras oncogene in PSCP compared to SEOC.

METHODS

Using single-strand conformational polymorphism analysis and cycle sequencing protocols, we evaluated our collection of 51 cases of PSCP for K-ras mutations and compared these findings with the experience in SEOC. We then examined 5 cases of PSCP for activation of ras proteins and MAP kinase to evaluate the potential involvement of the ras pathway in PSCP tumorigenesis.

RESULTS

We found only one K-ras mutation in our 51 cases (2%) of PSCP compared to three mutations in 46 cases (6.5%) of high-grade, late-stage SEOC. This was not significantly different (P > 0.10). In the single PSCP case with a K-ras mutation, the mutation was found in only one of five tumor sites tested. All four mutations involved a single nucleotide alteration in codon 12 (GGT to GTT, Gly to Val). To evaluate the ras pathway in PSCP, we used the known activated ras binding domain on Raf-1 to perform an assay to test for activated ras. We identified ras activation in 4 of 5 PSCP cases tested and, to confirm that the activation was functional, we tested and found similar activation of MAP kinase, a downstream mediator for K-ras expression.

CONCLUSIONS

K-ras mutations occur at low rates in both PSCP and high-grade, late-stage SEOC, and therefore K-ras mutations are not involved in the development of these two diseases. Finding the mutation in only one of multiple tumor sites in the PSCP case supports growing evidence for a multifocal origin of PSCP. Our findings of ras activation in four of five cases of PSCP suggest that ras activation by mechanisms other than genetic mutation is important for PSCP tumorigenesis.

Bis[N,N-bis(2-hydroxyethyl)dithiocarbamato]dimethyltin(IV)

The title compound, [Sn(CH(3))(2)(C(5)H(10)NO(2)S(2))(2)], has crystallographic mirror symmetry (C-Sn-C on mirror plane) and the coordination polyhedron around the Sn atom is a tetrahedron [C-Sn-C 139.3 (2) degrees and S-Sn-S 82.3 (1) degrees ] distorted towards a skew-trapezoidal bipyramid owing to an intramolecular Sn.S contact [3.0427 (6) A]. The molecules are linked into a linear chain by intermolecular O-H.O hydrogen bonds [O.O 2.646 (3) A].

Orthorhombic modification of triphenyltin 3-ureidopropionate

The Sn atom in catena-poly[triphenyltin(IV)-micro-(3-ureidopropionato-O(1):O(3))], [Sn(C(6)H(5))(3)(C(4)H(7)N(2)O(3))](n), is five-coordinate and has a trans-C(3)SnO(2) trigonal-bipyrmidal geometry arising from bridging through the O atom of the ureido fragment of an adjacent carboxylate group. Infinite chains propagate helically along the c axis and adjacent chains are linked by N-H.O [N.O 2.851 (4) A] hydrogen bonds into layers.

Bis(N,N-dimethylthiocarbamoylthio)acetic acid

Bis(N,N-dimethylthiocarbamoylthio)acetic acid, [(CH(3))(2)NC(=S)S](2)CHC(=O)OH or C(8)H(14)N(2)O(2)S(4), exists as a centrosymmetric hydrogen-bonded dimer [O.O 2.661 (3) A].

Bis(dicyclohexylammonium) adipate monohydrate

In the asymmetric unit of the title compound, 2C(12)H(24)N(+).C(6)H(8)O(4)(2-).H(2)O, the carboxylate ion lies about an inversion center, the water molecule is on a twofold axis and the sec-ammonium cation is in a general position. Cations link the oxygen ends of two adjacent carboxylate anions to form an eight-membered ring [N.O 2.683 (3) and 2.711 (3) A]. The ion pair propagates as a linear chain and adjacent chains are linked through the water molecules [O.O 2.966 (3) A] into layers.

Differential gene expression pattern between normal human trophoblast and choriocarcinoma cell lines: downregulation of heat shock protein-27 in choriocarcinoma in vitro and in vivo

OBJECTIVE

Our purpose was to identify potential differences in gene expression between normal trophoblast and choriocarcinoma cells.

METHODS

The Atlas human cDNA expression array hybridization technique was used to study the gene expression pattern in normal trophoblast and choriocarcinoma cell lines. Furthermore, to confirm heat shock protein-27 (Hsp-27) expression data, reverse transcriptase-PCR (RT-PCR), Western blot, and immunohistochemical analyses were used in vitro with cell lines and in vivo with paraffin sections.

RESULTS

The expression of nine genes was strongly different comparing a normal trophoblast cell line with choriocarcinoma cells on the Atlas membranes. Compared to normal trophoblast cells, six genes were upregulated and three were downregulated in choriocarcinoma cells. Furthermore, the downregulation of Hsp-27 in choriocarcinoma cells was confirmed both in vitro with cell lines and in vivo with paraffin sections using RT-PCR, Western blot, and immunohistochemical techniques.

CONCLUSION

cDNA expression array is a useful technique for identifying differentially expressed gene patterns in normal trophoblast and choriocarcinoma cells. The strong expression of Hsp-27 in placental villous trophoblast cells may play a role in trophoblast differentiation. The downregulation of Hsp-27 in choriocarcinoma may contribute to the extreme sensitivity of trophoblastic tumors to chemotherapy.

A new human topoisomerase III that interacts with SGS1 protein

Eukaryotic DNA topoisomerase III was first identified by studying the hyper-recombination and slow growth phenotypes of yeast mutants. Topoisomerase III interacts with DNA helicase SGS1 and the two proteins are involved in DNA recombination, cellular aging and maintenance of genome stability. A human homolog of topoisomerase III has previously been identified. Here we report the identification of cDNAs and the determination of gene structure for a second human topoisomerase III gene. This novel gene expresses three alternatively spliced transcripts, which encode gene products different in the putative DNA-binding C-termini. The largest gene product of the novel topoisomerase III was expressed and shown to interact with SGS1 protein and partially rescue the slow growth defect of a yeast topoisomerase III mutant. The presence of more than one human topoisomerase III is reminiscent of mammalian topoisomerase II, which has two genetically distinct isoforms with different expression patterns and probably different functions in mammalian cells.

Erbium:YAG laser resurfacing in Asians

BACKGROUND

Although laser resurfacing has become increasingly popular in the treatment of Caucasian skin, concerns about healing and postinflammatory pigmentary changes have limited its use in Asian skin.

OBJECTIVE

The purpose of this study was to determine the efficacy and safety of the Erbium(ER):YAG laser used in the treatment of Asian skin.

METHODS

Fifty Asian individuals with Rhytids, scars, pigmentary alteration, and a variety of cutaneous growth were treated with the Erbium:YAG laser. Patients were evaluated for clinical efficacy, wound healing, post-operative erythema, and post-inflammatory pigmentary changes.

RESULTS

Significant improvement was noted in all individuals. Shorter periods for re-epithelization and erythema duration were noted when compared to previously reported results following carbon dioxide laser resurfacing.

CONCLUSION

The Erbium:YAG laser is safe and effective in the treatment of Asian skin.

Hot-press molded poly(methyl methacrylate) matrix for solid-state dye lasers

A hot-press molding method was used to fabricate dye-doped poly(methyl methacrylate) (PMMA) slabs. Three rhodamine dyes, Rh640 (ClO(4)), Rh6G(ClO(4)), and Rh6G (Cl), were impregnated into the PMMA matrix first by dissolving the dye and granular PMMA in a solvent mixture of chloroform and methanol and then heating the mixture in vacuo at 175 degrees C to obtain a spongy preform. The powdered preform was molded into slabs at 175 degrees C and at <1 mbar, to eliminate the formation of bubbles in the slabs. We annealed the slabs for several hours to improve its optical homogeneity and hence its lasing efficiency. When pumped by a 1.5-mJ nitrogen laser, we obtained peak lasing efficiencies of 8% and 7.8%, respectively, for Rh6G (ClO(4)) and Rh640 (ClO(4)) in PMMA matrices. The lasing efficiency of Rh6G (ClO(4))-doped PMMA suffered a reduction rate of 0.012%/shot compared with 0.15%/shot for Rh640 (ClO(4))-doped PMMA. In contrast, Rh6G (Cl) in a hot-press molded PMMA slab suffered thermal bleaching that resulted in a low lasing efficiency of <1%; this can be explained by its absorption and fluorescence characteristics.

Energy-Transfer Dye Laser in SolGel Silica

Coumarin 460 transfers radiative energy to disodium fluorescein when solgel silica is doped with the dyes, producing disodium fluorescein lasing in superradiant mode at a 3.3% peak efficiency under low-energy transverse pumping by a 1.5-mJ N(2) laser, with disodium fluorescein being present at a concentration below its lasing threshold value.

DOC-2/hDab2, a candidate tumor suppressor gene involved in the development of gestational trophoblastic diseases

Gestational trophoblastic diseases comprise a spectrum of interrelated diseases including partial mole, complete mole and gestational choriocarcinoma. Using reverse transcriptase PCR (RT-PCR) analysis, we identified higher levels of DOC-2/hDab2 expression in the normal trophoblast cells in culture than in choriocarcinoma cell lines. Subsequent study using immunohistochemistry showed high levels of DOC-2/hDab2 protein expression in normal trophoblast tissues but significantly lower levels of expression in gestational trophoblastic disease tissues, particularly in complete mole and choriocarcinoma. When DOC-2/hDab2 was transfected into the choriocarcinoma cell lines, Jar, JEG and BeWo, the stable transfectants showed significantly reduced growth rate in culture. These data suggest that down regulation of DOC-2/hDab2 may play an important role in the development of gestational trophoblastic diseases.

DOC-2, a candidate tumor suppressor gene in human epithelial ovarian cancer

Using RNA fingerprinting (RAP) strategy and Northern blot analysis, we identified a differentially expressed sequence DOC-2 which is detectable in all normal human ovarian surface epithelial (HOSE) cell cultures but not in ovarian cancer cell lines and tissues. Subsequent cloning of DOC-2 from a cDNA library generated from the HOSE cells was carried out using the 3' and 5' RACE approach. A 3268 base pair full length cDNA of DOC-2 was isolated and sequenced. The predicted protein has a length of 770 amino acids. Homology search of all NCBI sequences indicated that the amino acid sequence of DOC-2 shares 93% homology with the mouse p96/mDab2 phosphoprotein and has a phosphotyrosine interacting domain (PID) and multiple SH3 binding motifs. Chromosomal localization by FISH showed that the DOC-2 gene is located on 5p13. Western blot analysis showed that the 105 kDa DOC-2 protein was down-regulated in all the carcinoma cell lines. In-situ immunohistochemistry performed on normal ovaries, and benign, borderline and invasive ovarian tumor tissues showed down regulation of DOC-2 protein particularly in serous ovarian tumor tissues. When DOC-2 was transfected into the ovarian carcinoma cell line SKOV3, the stable transfectants showed significantly reduced growth rate and ability to form tumors in nude mice. These data suggest that down-regulation of DOC-2 may play an important role in ovarian carcinogenesis.

Cloning and characterization of the 5'-flanking sequence for the human DNA topoisomerase II beta gene

Mammalian cells express two isoforms of type II DNA topoisomerase which are the intracellular targets of many structurally diverse antineoplastic agents. The levels of topoisomerase II isozymes are important determinants for the sensitivity of cells to the cytotoxicity of drugs that target topoisomerase II. To investigate whether the expression of topoisomerase II isoforms is coordinated and the mechanisms governing their expression in the context of drug resistance, the 5'-flanking sequence for the gene of human topoisomerase IIbeta isoform was cloned and characterized. The 5'-flanking region has a very high GC content and contains no canonical TATA box element. Two separate transcriptional start sites are located to an adenine and a guanine, 193 and 89 nucleotides, respectively, upstream from the ATG translation initiation codon. Except for a small region immediately upstream of the translation initiation codon, there is no obvious sequence homology between the 5'-flanking sequences of human topoisomerase IIbeta gene and the previously described alpha gene. Transient expression assays with different 5'- and 3'-deletions of the 5'-flanking region of the topoisomerase IIbeta gene have delineated regions important for transcriptional regulation of the gene. Interestingly, sequences within the first intron also contribute to the promoter activity. Gel mobility shift studies demonstrate that protein factors from the nuclear extracts can bind specifically to the downstream elements and may participate in transcriptional regulation.

Potential savings involved in the purchase of low-cost, high-volume medical commodities as established from a community hospital survey

Health technology refers to the instruments, equipment, drugs and procedures used in health care delivery, as well as the organizations supporting it. Health technology assessment, which is the process of conducting investigations to establish the criteria for efficacious, effective and efficient patient care, is becoming increasingly important in an era of diminishing resources. This survey of 39 community hospitals in southwestern Ontario found that improved purchasing strategies can result in substantial cost savings which can in turn be used to improve patient care. The study shows that optimizing the price of basic hospital commodities could save an average community hospital as much as $625,000 per year.

DNA topoisomerase II alpha expression is associated with alkylating agent resistance

Increased expression of DNA topoisomerase II alpha has been associated with resistance to certain DNA-damaging alkylating agents, but no causal relationship or mechanism has been established. To investigate this observation, we developed a model of topoisomerase II overexpression by transfecting a full-length Chinese hamster ovary topoisomerase II alpha into EMT6 mouse mammary carcinoma. Topoisomerase II alpha-transfected cell lines demonstrated continued topoisomerase II alpha mRNA and protein expression, which were undetectable in vector-only lines, in stationary phase (G0-G1). The topoisomerase II transfectants were approximately 5-10-fold resistant to the alkylating agents cisplatin and mechlorethamine. Upon release from G0-G1, the topoisomerase II transfectants demonstrated more rapid thymidine incorporation and shorter cell-doubling times than control cells. Purified topoisomerase II and nuclear extracts with topoisomerase II-decatenating activity bound to cisplatin-treated DNA with significantly greater affinity than to untreated DNA in a cisplatin concentration-dependent manner. These observations suggest that expression of topoisomerase II alpha may have a role in cellular resistance to antineoplastic alkylating agents. The mechanism for this may involve increased binding of topoisomerase II alpha to alkylating agent-damaged DNA.

Molecular cloning and characterization of the promoter for the Chinese hamster DNA topoisomerase II alpha gene

To investigate the mechanisms governing the expression of DNA topoisomerase II alpha, the Chinese hamster topoisomerase II alpha gene has been cloned and the promoter region analyzed. There are several transcriptional start sites clustered in a region of 30 base pairs, with the major one being 102 nucleotides upstream from the ATG translation initiation site. Sequencing data reveal one GC box and a total of five inverted CCAAT elements (ICEs) within a region of 530 base pairs upstream from the major transcription start site. Sequence comparison between the human and Chinese hamster topoisomerase II alpha gene promoter regions shows a high degree of homology centered at the ICEs and GC box. In vitro DNase I footprinting results indicate protection by binding proteins at and around each ICE on both DNA strands. However, no obvious protection was observed for the GC box. Competition gel mobility shift assays with oligonucleotides containing either the wild-type or mutated ICE sequences suggest that identical or similar proteins specifically bind at each ICE, although with different affinities for individual ICE sequences. Chloramphenicol acetyltransferase assays employing nested 5'-deletions of the 5'-flanking sequence of the gene demonstrate that the sequence between -186 and +102, which contains three proximal ICEs, is sufficient for near wild-type level of promoter activity. When these three ICEs were gradually replaced with sequences which do not interact with the binding proteins, reducing promoter activity of the resulted constructs was observed. In conjunction with results from footprinting and gel mobility shift studies, the transient gene expression finding suggests that the ICEs are functionally important for the transcriptional regulation of the topoisomerase II alpha gene.

Molecular cloning and identification of a point mutation in the topoisomerase II cDNA from an etoposide-resistant Chinese hamster ovary cell line

Topoisomerase II (Top II) is the target enzyme for many antineoplastic drugs such as epipodophyllotoxins, anthracyclines, and acridines. Cell lines with alterations in Top II are resistant to drugs that interact with the enzyme. Studies of the Top II from a Chinese hamster ovary line, VpmR-5, that is resistant to VP-16 and VM-26, demonstrated that it is very similar, qualitatively and quantitatively, to its normal counterpart except that DNA cleavage by the VpmR-5 enzyme is not stimulated by VP-16 or VM-26. To understand the basis for the drug-resistant phenotype, the Top II cDNAs were isolated from both Chinese hamster ovary (CHO) and VpmR-5 cells by cDNA cloning with lambda gt22, and the entire cDNAs were sequenced. A mutation of G-->A at nucleotide 1478 was the only alteration observed in the VpmR-5 Top II cDNA compared with the wild-type gene. The mutation in VpmR-5 was confirmed by sequencing DNA fragments amplified from the genomic DNA by the polymerase chain reaction. Southern blot hybridization analysis of genomic DNA demonstrated loss of a Top II allele in VpmR-5 probably occurred during the development of resistance to etoposide. The mutation in VpmR-5 changes amino acid 493 from arginine to glutamine and is located adjacent to a putative ATP binding site of Top II. Mutations in an analogous region have been identified in two human leukemia cell lines by amplification of segments of Top II cDNA with Taq DNA polymerase. Taken together, these observations suggest that mutations in this region of the gyrase B domain of mammalian topoisomerase II may be capable of conferring resistance to antineoplastic agents that interact with this enzyme.

Molecular characterization of a putative peroxidase gene of Drosophila melanogaster

We have identified genomic clones and corresponding cDNAs that encode a putative peroxidase of Drosophila melanogaster. The gene (DmPO) appears as a single copy gene located on the third chromosome at position 89 D/E. It is interrupted by seven small introns and one unusually large 5' intron (about 11 kb). Sequence analysis of the cDNA showed an open reading frame of 690 amino acids resulting in a protein of 77 kDa. The deduced amino acid sequence reveals an overall homology to myeloeosinophil and thyroid peroxidase, a human superfamily of peroxidases.

The reversal of effects of methotrexate on toxicity and glucose transport reduction by thymidine in Ehrlich ascites tumor bearing mice

Methotrexate (MTX) suppressed the growth of Ehrlich ascites tumor cells in vivo and reduced the cellular uptake of glucose and the density of glucose transporters on the tumor cell surface. MTX inhibition of tumor growth was partially prevented by concurrent administration of thymidine. At the same time, the rate of cellular glucose uptake, the density of glucose transporters on the cell as well as the extent of thymidine, uridine and leucine incorporation were significantly increased.

Prevention by thymidine against toxicity and glucose uptake inhibition of methotrexate on cultured Ehrlich ascites tumour cells

Methotrexate (MTX) arrested cell growth and inhibited 2-deoxy-D-glucose uptake of Ehrlich ascites tumour cells in vitro. The changes of glucose concentrations in the culture media did not affect the degree of suppression of cell growth by MTX. Thymidine (dThd) protected against the toxic effect of MTX on the cells. It also prevented the inhibition effect on glucose uptake of the cells by MTX. MTX significantly suppressed the maximal uptake rate of glucose (Vmax) while addition of dThd alleviated the suppression. The half-saturation constant of the uptake (Km) remained constant.