bluuebunny/crossref_metadata_2025 huggingface dataset:
Evidence for Vasculoprotective Effects of ETB Receptors in Resistance Artery Remodeling in Diabetes
Authors: Sachidanandam Kamakshi , Portik-Dobos Vera , Harris Alex K. , Hutchinson Jim R. , Muller Erin , Johnson Maribeth H. , Ergul Adviye
Published: September 2007

OBJECTIVE—Vascular remodeling, characterized by extracellular matrix deposition and increased media-to-lumen (M/l) ratio, contributes to the development of microvascular complications in diabetes. Matrix metalloproteinases (MMPs) play an important role in the regulation of extracellular matrix (ECM) turnover and vascular remodeling. Vasoactive factor endothelin (ET)-1 not only causes potent vasoconstriction but also exerts profibrotic and proliferative effects that change vessel architecture, which makes it a likely candidate for a key role in vascular complications of diabetes. Thus, this study investigated the regulation of MMP activity of resistance arteries under mild-to-moderate diabetes conditions, as seen in type 2 diabetes, and the relative role of ET receptors in this process.

RESEARCH DESIGN AND METHODS—Vessel structure, MMP activity, and ECM proteins were assessed in control Wistar and diabetic Goto-Kakizaki (GK) rats treated with vehicle, ETA receptor antagonist atrasentan (5 mg · kg−1 · day−1), or ETB receptor antagonist A-192621 (15 mg · kg−1 · day−1) for 4 weeks.

RESULTS—M/l ratio was increased in diabetes. Atrasentan prevented this increase, whereas A-192621 caused further thickening of the medial layer. Increased MMP-2 activity in diabetes was prevented by atrasentan treatment. Collagenase activity was significantly decreased in diabetes, and while ETA antagonism improved enzyme activity, ETB blockade further reduced collagenase levels. Accordingly, collagen deposition was augmented in GK rats, which was reversed by atrasentan but exacerbated with A-192621.

CONCLUSIONS—ET-1 contributes to the remodeling of mesenteric resistance arteries in diabetes via activation of ETA receptors, and ETB receptors provide vasculoprotective effects.
Serum Cystatin C Predicts Progression of Subclinical Coronary Atherosclerosis in Individuals With Type 1 Diabetes
Authors: Maahs David M. , Ogden Lorraine G. , Kretowski Adam , Snell-Bergeon Janet K. , Kinney Gregory L. , Berl Tomas , Rewers Marian
Published: September 2007

OBJECTIVE—Renal function is an important determinant of coronary atherosclerosis, and serum cystatin C is a novel accurate measure of glomerular filtration rate (GFR) and a predictor of cardiovascular events and mortality. We hypothesized that in individuals with type 1 diabetes, cystatin C would 1) predict progression of subclinical coronary atherosclerosis (SCA) and 2) be a stronger predictor of SCA than serum creatinine, GFR (estimated by the Cockcroft-Gault [GFRCG] and Modification of Diet in Renal Disease [GFRMDRD] formulas), and albumin excretion rate.

RESEARCH DESIGN AND METHODS—Coronary artery calcification was measured twice, using Imatron C-150 Ultrafast CT, over a 2.5 ± 0.4-year interval in 509 adults with type 1 diabetes (42% male, age 36 ± 9 years, duration 23 ± 9 years). SCA progression (n = 131) was defined as a >2.5 increase in square root calcium volume score or development of clinical coronary artery disease. Predictors of SCA progression were examined in a model selected by stepwise logistic regression and an a priori–determined model. Next, each measure of renal function was inserted into the stepwise model, one at a time, and Akaike information criterion was used to compare the fit of the competing models.

RESULTS—The stepwise model included cystatin C (odds ratio 1.44, 95% CI 1.00–2.18, P = 0.048), age, baseline coronary artery calcification, sex, diabetes duration, systolic blood pressure, and HDL. The stepwise model had a better fit than any of the competing models with serum creatinine, GFRCG, GFRMDRD, or albumin excretion rate replacing cystatin C.

CONCLUSIONS—In individuals with type 1 diabetes, cystatin C modestly predicts SCA.
IGF-1 and Leptin Associate With Fetal HDL Cholesterol at Birth
Authors: Nelson Scott M. , Freeman Dilys J. , Sattar Naveed , Johnstone Frank D. , Lindsay Robert S.
Published: September 2007

OBJECTIVE— Offspring of mothers with type 1 diabetes (OT1DM) demonstrate increased fat deposition, hyperinsulinemia, and hyperleptinemia in utero. We examined the influence of maternal diabetes on cord lipids at birth and relationship to body composition, cord insulin, leptin, and other hormonal measures.

RESEARCH DESIGN AND METHODS— We performed an observational study measuring fetal, HDL, and LDL cholesterol; triglycerides; and nonesterified fatty acids (NEFAs) in a total of 139 OT1DM and 48 control subjects at birth and assessed cross-sectional relationships with birth weight, fetal insulin, leptin, adiponectin, and IGF-1.

RESULTS— Concentrations of total cholesterol (male OT1DM [mean ± SD] 1.49 ± 0.45 mmol/l and male control subjects 1.74 ± 0.33 mmol/l; P < 0.001), HDL cholesterol (0.53 ± 0.21 and 0.74 ± 0.19 mmol/l, respectively; P < 0.001), and NEFA (median 0.17 [interquartile range 2.30−2.95] and 0.21 [0.18–0.36], respectively; P < 0.001) were significantly lower in male OT1DM, with no significant differences in female subjects. Differences in male subjects were independent of mode of delivery. Cord lipids were unrelated to birth weight in OT1DM and did not show consistent relationships with fetal insulin. Unexpectedly, IGF-1 was a strong correlate of HDL cholesterol in control subjects (r = 0.40, P = 0.002) and OT1DM (r = 0.32, P < 0.001) but a negative correlate of triglycerides in control subjects (r = −0.48, P < 0.001) and OT1DM (r = −0.21, P = 0.004), with these relationships present in both sexes. In OT1DM, leptin was also independently correlated (negatively, P < 0.001) with HDL cholesterol in male and female subjects.

CONCLUSIONS— Maternal diabetes is associated with significant alterations in lipid levels in male fetuses. IGF-1, leptin, and male sex rather than insulin may be the major determinants of HDL cholesterol and triglycerides in utero.
Orexins Control Intestinal Glucose Transport by Distinct Neuronal, Endocrine, and Direct Epithelial Pathways
Authors: Ducroc Robert , Voisin Thierry , El Firar Aadil , Laburthe Marc
Published: September 2007

OBJECTIVE—Orexins are neuropeptides involved in energy homeostasis. We investigated the effect of orexin A (OxA) and orexin B (OxB) on intestinal glucose transport in the rat.

RESEARCH DESIGN AND METHODS AND RESULTS—Injection of orexins led to a decrease in the blood glucose level in oral glucose tolerance tests (OGTTs). Effects of orexins on glucose entry were analyzed in Ussing chambers using the Na+-dependent increase in short-circuit current (Isc) to quantify jejunal glucose transport. The rapid and marked increase in Isc induced by luminal glucose was inhibited by 10 nmol/l OxA or OxB (53 and 59%, respectively). Response curves to OxA and OxB were not significantly different with half-maximal inhibitory concentrations at 0.9 and 0.4 nmol/l, respectively. On the one hand, OxA-induced inhibition of Isc was reduced by the neuronal blocker tetrodotoxin (TTX) and by a cholecystokinin (CCK) 2R antagonist, indicating involvement of neuronal and endocrine CCK-releasing cells. The OX1R antagonist SB334867 had no effect on OxA-induced inhibition, which is likely to occur via a neuronal and/or endocrine OX2R. On the other hand, SB334867 induced a significant right shift of the concentration-effect curve for OxB. This OxB-preferring OX1R pathway was not sensitive to TTX or to CCKR antagonists, suggesting that OxB may act directly on enterocytic OX1R. These distinct effects of OxA and OxB are consistent with the expression of OX1R and OX2R mRNA in the epithelial and nonepithelial tissues, respectively.

CONCLUSIONS—Our data delineate a new function for orexins as inhibitors of intestinal glucose absorption and provide a new basis for orexin-induced short-term control of energy homeostasis.
Economic Consequences of the Obese
Authors: Runge C. Ford
Published: September 2007

The private and social costs of obesity have many causes, and their consequences can be grimly predicted with only rough accuracy. Among the most devastating is the increased incidence of diabetes, of which 60% can be directly attributed to weight gain. There are now about one billion people worldwide who are overweight or obese, compared with 850 million who are chronically underweight. It is estimated that the number of people worldwide with diabetes will increase from 175 million in 2000 to 353 million in 2030, with India and China together accounting for 24% of the total in 2050. Obesity and its economic costs are borne on three levels. At an individual level, obesity imposes costs by limiting personal opportunity in many ways, only some of which can be quantified. In the workplace (assuming the obese are employed, which they may not be, due in part to their condition), costs are borne by employers due to lost productivity, absences, underperformance, and higher insurance premia, which in the aggregate are quite large. Finally, obesity affects expenditures by local, state, and national governments, where programs compensate for or cover some of the private and workforce costs of illness and unemployment.
The Contribution of Splanchnic Fat to VLDL Triglyceride Is Greater in Insulin-Resistant Than Insulin-Sensitive Men and Women
Authors: Hodson Leanne , Bickerton Alex S.T. , McQuaid Siobhán E. , Roberts Rachel , Karpe Fredrik , Frayn Keith N. , Fielding Barbara A.
Published: September 2007

OBJECTIVE—We aimed to determine differences in the postprandial contributions of different fatty acid sources to VLDL triglycerides (TGs) in healthy men and women with varying degrees of insulin resistance.

RESEARCH DESIGN AND METHODS—Insulin-resistant (n = 11) and insulin-sensitive (n = 11) men and women (n = 6) were given an intravenous infusion of [2H2]palmitic acid to investigate systemic nonesterified fatty acid (NEFA) incorporation into VLDL TGs. Participants were also fed a mixed meal containing [U-13C]palmitic acid to investigate the contribution of dietary fatty acids to VLDL TG production. Blood samples were taken over the following 6 h. Separation of VLDL was performed by density gradient ultracentrifugation and immunoaffinity techniques specific to apolipoprotein B-100.

RESULTS—Insulin-resistant and insulin-sensitive men had similar postprandial chylomicron and chylomicron remnant TG concentrations, but insulin-resistant men had higher postprandial VLDL TG concentrations (median [range]; area under the curve 485 μmol/l [123–992] vs. 287 μmol/l [162–510]; P < 0.05). At 360 min, most of the difference in VLDL TGs was accounted for by an additional contribution from splanchnic fat (means ± SE; 331 ± 76 μmol/l vs. 89 ± 25 μmol/l; P < 0.01). The contribution of fatty acids from endogenous systemic NEFAs was similar across the groups, as were dietary fatty acids. There was no difference in the VLDL TG concentration or the contribution of different fatty acid sources between insulin-sensitive men and women.

CONCLUSIONS—In the postprandial period, the only sources of fatty acids for VLDL TG production to differ in the insulin-resistant compared with the insulin-sensitive men are those derived from splanchnic sources.
Estimation of β-Cell Mass by Metabolic Tests
Authors: Robertson R. Paul
Published: September 2007

This Perspectives in Diabetes addresses the accuracy of metabolic testing as a measure of pancreatic islet β-cell mass in vivo in animals and in humans. The impetus for framing this question lies in the current intense interest in determining the fate of β-cell mass in transplanted islets, i.e., does it decrease, increase, or remain the same over time, as well as ascertaining whether drugs that enhance incretin levels, and consequently enhance glucose-induced insulin secretion, might also preserve β-cell mass. An important methodology recently making scientific strides in this arena is positron emission tomography (PET). The central question this Perspectives in Diabetes raises is whether it is likely that PET will provide significant advantages over the metabolic methods already in hand and routinely used to estimate β-cell mass. This article examines the fidelity with which published metabolic data correlate with independent measures of β-cell mass across multiple species. Correlation coefficients in the general range of r = 0.80 are routinely obtained and are robust for in vivo research. Whether PET can significantly improve on these correlations, given its inherent limitations in measurement sensitivity, remains to be seen. It is clear that investigators developing PET methodology to estimate β-cell mass should at the same time incorporate metabolic measures into their studies so that side-by-side comparisons of the accuracy of the two experimental approaches can be made.
Evidence of Increased Inflammation and Microcirculatory Abnormalities in Patients With Type 1 Diabetes and Their Role in Microvascular Complications
Authors: Devaraj Sridevi , Cheung Anthony T. , Jialal Ishwarlal , Griffen Steven C. , Nguyen Danh , Glaser Nicole , Aoki Thomas
Published: September 2007

OBJECTIVE—Type 1 diabetes is associated with increased microvascular complications and inflammation. The monocyte-macrophage is a pivotal cell in atherogenesis. There are scanty data on noninvasive measures of microvascular abnormalities and inflammation in type 1 diabetic subjects with microvascular complications. Thus, we examined systemic and cellular biomarkers of inflammation in type 1 diabetic patients with microvascular complications (T1DM-MV patients) and type 1 diabetic patients without microvascular complications (T1DM patients) compared with matched control subjects and determined the microcirculatory abnormalities in the T1DM and T1DM-MV patients using computer-assisted intravital microscopy (CAIM).

RESEARCH DESIGN AND METHODS—Fasting blood, 24-h urine, and CAIM measurements were obtained from the T1DM and T1DM-MV patients and matched control subjects. C-reactive protein, E-selectin, nitrotyrosine, monocyte superoxide, and cytokines were elevated in the T1DM and T1DM-MV patients compared with control subjects (P < 0.01).

RESULTS—Severity index, as assessed by CAIM, was significantly increased in the T1DM and T1DM-MV patients compared with the control subjects (P < 0.001). There was a significant increase in C-reactive protein, nitrotyrosine, vascular cell adhesion molecule and monocyte superoxide anion release, and interleukin-1 release in T1DM-MV compared with T1DM patients (P < 0.05). T1DM-MV patients had significantly increased CAIM severity index and microalbumin-to-creatinine ratio compared with T1DM patients (P < 0.05). Furthermore, pp38MAPK, pp65, and pERK activity were significantly increased in monocytes from the T1DM and T1DM-MV patients compared with those from the controls subjects, and pp38MAPK and pp65 activity were significantly increased in the T1DM-MV compared with the T1DM patients (P < 0.01).

CONCLUSIONS—T1DM-MV patients have increased inflammation compared with T1DM patients. CAIM provides an effective biomarker of microvascular complications, since it is significantly elevated in T1DM-MV compared with T1DM patients and can be monitored following therapies targeted at improving inflammation and/or microvascular complications of type 1 diabetes.
Gross Motor Development of Children With Hurler Syndrome After Umbilical Cord Blood Transplantation
Authors: Dusing Stacey C , Thorpe Deborah E , Poe Michele D , Rosenberg Angela E , Mercer Vicki S , Escolar Maria L
Published: September 2007

Background and Purpose

Little is known about the gross motor development of children with Hurler syndrome who have undergone umbilical cord blood transplantation (UCBT). The purpose of this study was to provide a description of gross motor development in children with Hurler syndrome after UCBT.

Subjects and Method

Longitudinal changes in gross motor abilities were documented on the gross motor subtests of the Peabody Developmental Motor Scales, second edition (PDMS-2) for 21 children with Hurler syndrome. Each child was assessed between 1 and 6 times after UCBT. The participants had a mean age (±SD) of 32.2±16.0 months at the time of the first assessment. The mean time (±SD) between UCBT and the first assessment was 16.2±16.5 months.

Results

The participants had marked gross motor delays, with a mean gross motor quotient 2 standard deviations below the mean for children who were developing typically. The rate of development differed between the subtests of the PDMS-2. The participants gained abilities at the slowest rate on the stationary subtest and at the fastest rate on the locomotor subtest.

Discussion and Conclusion

The participants had varying degrees of delay in different gross motor domains. While gaining new gross motor abilities over time, these children continued to have delays up to 48 months after UCBT. Physical therapists treating children with Hurler syndrome after UCBT should use assessment tools that will capture these differences and should individualize treatment plans accordingly. Additional research is needed to document the efficacy of physical therapy intervention with this population.
A two‐degree‐of‐freedom time‐optimal solution for hard disk drive servo problems
Authors: Hu Shaohua , Gao Zhiqiang
Published: September 2007

This paper deals with the hard disk drive (HDD) servo problems. A novel discrete time‐optimal control solution is proposed in a two‐degree‐of‐freedom (2DOF) structure, employing both the feedback and feedforward controllers. The time‐optimal feedback controller, derived from a simple, double integral plant model, shows remarkable robustness and disturbance rejection in the presence of resonant modes, measurement noises and position and torque disturbances. It eliminates the needs for two separate controllers for track‐seeking and track‐following operations. The proposed feedforward controller in this 2DOF structure proves to be quite beneficial in reducing the seek time. It also allows the feedback controller to be tuned more aggressively, which helps to improve the quality of track following. The proposed control scheme offers a novel basic control structure for HDD servo, upon which numerous further improvements can be made. It is successfully tested in simulation on an industrial 13.0‐kTPI HDD. Copyright © 2007 John Wiley & Sons, Ltd.
On the Threshold of Rationalism
Authors: Peckham Andrew , Rattray Charles , Schmiedeknecht Torsten
Published: September 2007

No longer a leading architectural trend, Rationalism has fallen out of fashion. At best ‘marginalised’, even its tenets appear questionable. Guest‐editors Andrew Peckham, Charles Rattray and Torsten Schmiedeknecht describe what motivated them to uncover and reassess the Rationalist sensibility among current European practices. Copyright © 2007 John Wiley & Sons, Ltd.
The Employment of Reason
Authors: Rattray Charles
Published: September 2007

Rationalism in the Netherlands is characterised by pragmatism. As Charles Rattray explains it is a practical bent that was driven in the 20th century by the exigencies of building cheaply and quickly a large amount of social housing on a relatively small amount of land. It is a strand that has been underscored by a belief in reason across time and a confidence in an analytical approach. Copyright © 2007 John Wiley & Sons, Ltd.
Selected French Projects
Authors: Abram Joseph
Published: September 2007

French architecture is on the brink of change. If Rationalist tendencies achieve critical mass, they could prove the catalyst for a dynamic and significant cultural moment. Joseph Abram describes some of the buildings that display the full ‘spectrum of possibilities’ of the reasoned approach in France, from the urban poetics of Patrick Berger to the typological and technological pragmatism of Jacques Ferrier. Copyright © 2007 John Wiley & Sons, Ltd.
Pedro and Inês Bridge, Coimbra, Portugal
Authors: Melvin Jeremy
Published: September 2007

Jeremy Melvin describes how Cecil Balmond of Arup and Antonio Adao da Fonseca have created ‘the first bridge that does not meet in the middle’ for Portugal's oldest university town. The bridge's dislocated apex provides not only a focus for a formal investigation into dynamic symmetry, but also a layered narrative that makes sense of its historical setting. Copyright © 2007 John Wiley & Sons, Ltd.
Brigitta Zics: Working on Interactive Potential
Authors: Croci Valentina
Published: September 2007

Valentina Croci kicks off a new series on interactive technologies with an investigation of the integrated, interdisciplinary research of the new media artist Brigitta Zics. Zics' projects throw light on how conventional architecture might learn from the interactive, placing a greater understanding on the sensory and the user's perceptual experience of a particular space. Copyright © 2007 John Wiley & Sons, Ltd.
Part 1: Some Basic Premises for Green Design
Authors: Yeang Ken
Published: September 2007

Sustainable or green design is notoriously ill‐defined. As a comparatively young discipline it is up for grabs and up for interpretation. In a new three‐part series, Ken Yeang, who has been designing green architecture for more than three decades, provides some much‐needed parameters. Copyright © 2007 John Wiley & Sons, Ltd.
AuPt Alloy Nanoparticles for CO‐Tolerant Hydrogen Activation: Architectural Effects in Au‐Pt Bimetallic Nanocatalysts
Authors: Zhou S. , Jackson G. S. , Eichhorn B.
Published: September 2007

Colloidal suspensions of AuPt alloy nanoparticles (NPs) were prepared by using a rapid butyllithium reduction of Au3+ and Pt4+ precursors in oleylamine. The resulting 2.5 nm (av) particles were characterized by TEM with EDX, XRD, XPS and UV‐vis spectroscopy. With less butyllithium, nanowires are formed from fused NPs and grow to 100 nm in length. The activities of three different AuPt NP architectures (alloy, contact aggregate and monometallic NPs) were evaluated for catalytic hydrogen oxidation in CO‐contaminated fuel streams (1.0 % Pt loadings in Al2O3 supports). The alloy catalyst showed superior H2 and CO oxidation activity, was unaffected by iron promoters and appears to operate by a different mechanism. The heteroaggregate showed a marked improvement in activity with iron promoters and is more selective for CO oxidation.
The Effects of Some Operational Parameters in Photodegradation of Benzylamine and Aniline and Their Kinetics in Aqueous Suspension of TiO2 and Pt–Loaded TiO2
Authors: Montazerozohori Morteza , Habibi Mohammad Hossein , Joohari Shiva , Khodadostan Vida
Published: September 2007

Photocatalytic degradation of benzylamine and aniline on TiO2, Pt‐modified TiO2, ZnO and ZnS in aqueous solution has been investigated. The degradation of the compounds follows a pseudo‐first‐order kinetics according to Langmuir‐Hinshelwood model. The degradation process of benzylamine and aniline was evaluated by ninhydrin spectrophotometric method using UV‐visible spectrophotometer in λmax= 538 and 525 nm, respectively. The results showed the order of Pt/TiO2> TiO2> ZnO> ZnS for photocatalytic activity. In addition increasing of the Pt‐loading was found to enhance the degradation rate of the compounds up to the optimal amount of 5wt. % onto the surface of TiO2 so that the rates of degradation were increased about two times. Rate constants for photodegradation of benzylamine and aniline were found to be 1.4×10‐3 min‐1 and 0.7×10‐3 min‐1 for TiO2 as photocatalyst, while 2.7×10‐3 min‐1 and 1.7×10‐3min‐1 for (5 wt.%) Pt/TiO2 as photocatalyst. Running the reactions in various pH (5‐11), indicated that the pH= 8 and 10 or Higher are the optimum pH for photocatalytic degradation of benzylamine and aniline respectively. The effects of some other parameters such as amount of photocatalyst, flux of oxygen and irradiation time were evaluated. Furthermore, the Langmuir‐Hinshelwood rate constant kr and adsorption constant KA for the titled compounds are reported.
Kinetics of bimolecular radical decay in different polymeric matrices
Authors: Medvedevskikh Y. G. , Kytsya A. R. , Holdak O. S. , Khovanets G. I. , Bazylyak L. I. , Zaikov G. E.
Published: September 2007

Using electron spin resonance spectroscopy, we have studied the kinetics of the bimolecular decay of methacrylic macroradicals in networked and unnetworked polymeric matrices. We have determined that macroradical decay in the entire range of temperatures (20–70°C) is definitely ordered to a second‐order kinetic reaction equation. We have estimated the activation parameters of the process. Using Smolukhovsky's and Einstein's equations and the fractal dependence of the conformation radius of the macroradical on its polymerization degree, we have obtained an equation for the constant of bimolecular radical decay under diffusion conditions. This equation is in good agreement with all the experimental data and possesses a commonness permitting its use in the analysis of bimolecular chain termination in different reaction zones via polymerization processes until high conversions. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Study of cure kinetics of diglycidyl ether of bisphenol A with Ni(II) and Cu(II) complexes of benzil bisthiosemicarbazone
Authors: Ghaemy Mousa , Behmadi Hossein , Barghamadi Mohammad
Published: September 2007

The curing reaction kinetics of the diglycidyl ether of bisphenol A (DGEBA)‐based epoxy and inorganic complexes curing agents based on Ni(II) and Cu(II) chelates with benzil bisthiosemicarbazone LH6 as a ligand was studied using differential scanning calorimetry (DSC). The curing reaction with the ligand and the complexes was characterized by high cure onset and peak maximum temperatures. The kinetics of the curing reaction was evaluated using three kinetic models; Kissinger, Ozawa‐Flynn‐Wall, and Málek. For the NiLH4 and CuLH4 the average values of Ea were calculated to be 82.3 and 116 kJ/mol, respectively. For both complexes, their activation energies at 40 and 30 phr are equal. The values of activation energy (Ea), and initial and maximum temperatures of the exothermic curing peak (Ti and Tp) of the ligand are smaller than those of the complexes, and the values of these parameters of the DGEBA/NiLH4 system are lower than those of DGEBA/CuLH4 system. These results indicate the order of reactivity of LH6 ≫ NiLH4 ≫ CuLH4 toward epoxy resin. The effect of hardener concentration, heating rate, and type of metal ion on the cure kinetic parameters and the shape of DSC thermograms were investigated. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Synthesis and characterization of carboxymethyl chitosan containing functional ultraviolet absorber substituent
Authors: Yu Shujuan , Du Jie , Zheng Yubin , Yan Li
Published: September 2007

A series of carboxymethyl chitosan (CMC) with 2.4‐dihydoxybenzophenone (UV‐0) substituent were synthesized by the Mannich reaction of CMC hydrochloride and UV‐0 in the solvent of methanol and water. The different molar degree of substitution (MS) was achieved by changing the UV‐0 content. The effects of MS on ultraviolet absorbability, crystallinity, moisture‐absorption and ‐retention property, and photostability were investigated respectively. The obtained products were characterized by means of Fourier transform infrared spectra (FTIR), proton nuclear magnetic resonance spectroscopy (1H NMR), X‐ray diffraction, and UV spectrophotometer. It was found that the grafted products were water‐soluble, and the increased MS values could enhance the moisture‐retention property and photostability, while decreased the crystallinity and moisture‐absorption property. The ultraviolet absorption peaks became stronger by introducing UV‐0 into the CMC backbones. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Probe dependency of polymer‐plasticizer and polymer‐polymer interaction parameters in inverse gas chromatography
Authors: Huang Jan‐Chan
Published: September 2007

Inverse gas chromatography has been widely used to determine the Flory–Huggins parameter, χ, between a plasticizer and a polymer, or between two polymers. Many studies showed that interaction parameters may be probe dependent. In a recent study it was proposed that, when a specific interaction occurred between two polymers, the probes had less interaction with the polymers, leading to a lower solubility parameter for polymer blends than the volume average of the components. An equation was derived to relate the probe dependency to the deviation of solubility parameter of polymer mixtures. Here this approach is applied to plasticized poly(vinyl chloride) (PVC) and a copolymer, and to poly(vinylidene fluoride)–poly(ethyl methacrylate) blends. For a PVC and epoxidized oil system the relative deviation of specific retention volume showed two trends, with saturated hydrocarbons as one group, and polar and aromatic probes as another group. For the poly(vinylidene fluoride)/poly(ethyl methacrylate) system the plot of retention volume deviation versus solubility parameter of probes also showed separate trends for n‐alkanes, esters, and alcohols. But the plot of ϕ2ϕ3RT(χ23/V2) versus solubility parameter had better linearity for the systems studied. The slope of this plot was used as an indicator for miscibility. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Blended hybrids based on silsesquioxane–OH and epoxy resins
Authors: Lu Tingli , Liang Guozheng , Peng Yaoli , Chen Tao
Published: September 2007

Blended hybrids based on silsesquioxane cyclohexyl trisilanol [STOH; i.e., (c‐C6H11)7Si7O9(OH)3] and epoxy resin 4,5‐epoxyhexyl‐1,2‐dimethyl acid diglycidyl ester (TDE‐85) were prepared with good compatibility of STOH up to 5 wt % with TDE‐85. The blended hybrid resins, with various STOH additions, were cured by 4,4′‐diaminodiphenylsulfone, and the curing reactions were investigated with differential scanning calorimetry. The incorporation of STOH increased the curing reaction of TDE‐85 for three active hydrogens existing in the STOH molecule. The storage moduli and glass‐transition temperatures of the cured hybrid resins were studied with dynamic mechanical analysis. The cured hybrids had higher storage moduli than the pure epoxy resins at lower temperatures and increased slightly even when the temperature was above the glass‐transition temperature. Two peaks appearing in tan δ curves indicated the block copolymer structure and two different glass‐transition temperatures of the cured hybrid resins. The thermal stability and flame retardancy of the cured hybrid resins were investigated with thermogravimetric analysis and limited oxygen index values, respectively. The results showed that introducing silsesquioxane–OH units into epoxy resins could improve the thermal stability and flame retardancy of the resins. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Synthesis and Pharmacological Evaluation of New 1‐[3‐(4‐Arylpiperazin‐1‐yl)‐2‐hydroxypropyl]‐pyrrolidin‐2‐one Derivatives with Anti‐arrhythmic, Hypotensive, and α‐Adrenolytic Activity
Authors: Kulig Katarzyna , Sapa Jacek , Maciag Dorota , Filipek Barbara , Malawska Barbara
Published: September 2007

A series of novel arylpiperazines bearing a pyrrolidin‐2‐one fragment was synthesized and evaluated for the binding affinity of the α1‐ and α2‐adrenoceptors (AR) and for the antiarrhythmic and hypotensive activities of the compounds. The most potent and selective compound 1‐[2‐hydroxy‐3‐[4‐[(2‐hydroxyphenyl)piperazin‐1‐yl]propyl]pyrrolidin‐2‐one 8 binds with pKi = 6.71 for α1‐AR. Derivative 8 was also the most active in the prophylactic antiarrhythmic test in adrenaline‐induced arrhythmia in anaesthetized rats. Its ED50 value equals 1.9 mg/kg (i.v.). Compounds with substituents such as a fluorine atom 4, a methyl 5, or a hydroxyl 8 group, or two substituents such as fluorine/chlorine atoms and methoxy groups in the phenyl ring, significantly decreased the systolic and diastolic pressure in normotensive anesthetized rats at a dosages of 5–10 mg/kg (i.v.). It was found that the presence of the piperazine ring and a hydroxy group in the second position of the propyl chain are critical structural features in determining the affinity of the compounds tested.
Pai syndrome: First patient with agenesis of the corpus callosum and literature review
Authors: Castori Marco , Rinaldi Rosanna , Bianchi Aurelia , Caponetti Aurelio , Assumma Marcello , Grammatico Paola
Published: September 2007

BACKGROUND:

Pai syndrome (PS) is a rare regional developmental defect of the face, mainly characterized by the variable association of midline cleft of the upper lip (MCL), duplicated maxillary median frenulum, and midline facial cutaneous and midanterior alveolar process polyps. Its entire clinical spectrum is still poorly delineated and the etiology remains unknown.

CASE:

We describe a 1‐month‐old boy presenting with MCL, left nostril hamartomatous mass, midline pedunculated polyp originating from the columella base, midline alveolar cleft, duplication of the upper median frenulum, unilateral persistent papillary membrane, lipoma of the corpus callosum, and additional minor facial dysmorphism. This patient also presents with agenesis of the corpus callosum, which has never been reported in PS. Literature review was carried out comparing clinical data of the 20 previously published patients with those observed in the present case.

CONCLUSIONS:

The minimum diagnostic criteria for PS has been fixed in one or more hamartomatous nasal polyps plus MCL (with or without cleft alveolus) and/or midanterior alveolar process congenital polyp. Additional common ancillary findings include duplicated median maxillary frenulum, hypertelorism, nasal cleft, midfrontal skin tags, and ocular and CNS structural abnormalities. However, mental retardation is only an occasional feature and seems to be related to coexisting conditions (such as chromosome imbalance). Literature review shows that PS is etiologically heterogeneous, as it may result from chromosome abnormalities and environmental/stochastic events, as well as de novo mutations. Birth Defects Research (Part A) 2007. © 2007 Wiley‐Liss, Inc.
Aplasia cutis congenita with skull defect in a monozygotic twin after exposure to methimazole in utero
Authors: Iwayama Hideyuki , Hosono Haruki , Yamamoto Hikaru , Oshiro Makoto , Ueda Norishi
Published: September 2007

BACKGROUND:

Aplasia cutis congenita (ACC) is a condition in which localized or widespread areas of skin are absent at birth. Defective lesions show complete absence of all layers of skin, occasionally extending to skull or dura. ACC is etiologically heterogeneous; many different etiologies including teratogens have been documented.

CASE:

We describe the first reported case of a monozygotic twin with ACC after exposure to methimazole in utero. The female patient was born at 36 weeks gestation as the first child of monozygotic twins. The mother received methimazole between the 11th and 17th weeks of pregnancy because of transient hyperthyroidism. The second child did not have ACC. The patient had defects of the scalp, skull, and dura (7 × 5 cm) on the sagittal line of the parieto‐occipital region. No other malformations were noted. The scalp defect has been treated daily with sterile physiological saline and petrolatum dressing in addition to intravenous antibiotics. Trafermin, a recombinant human fibroblast growth factor, was sprayed from day 6 to promote epithelialization of the scalp defect. On day 21, she had high fever due to infection of the defect lesion, which was controlled by povidone iodine dressing and intravenous antibiotics. The defect of the scalp was well healed after 6 weeks, but the skull defect remained unclosed.

CONCLUSIONS:

We describe a rare case of a monozygotic twin with ACC and skull defect after methimazole exposure in utero. The findings of our case suggest that methimazole is a potential teratogen of ACC. Birth Defects Research (Part A) 2007. © 2007 Wiley‐Liss, Inc.
Precursor‐directed biosynthesis of stilbene methyl ethers in Escherichia coli
Authors: Katsuyama Yohei , Funa Nobutaka , Horinouchi Sueharu
Published: September 2007

Stilbenes are bioactive compounds that show beneficial effects for humans, such as anti‐tumor activity and survival improvement. Resveratrol, a representative of stilbenes and showing various health‐improving activities, is rapidly metabolized in humans, and modified resveratrols are therefore desired as anti‐cancer drugs and dietary polyphenols. An Escherichia coli system, in which an artificial stilbene biosynthetic pathway, including steps of phenylalanine ammonia‐lyase, 4‐coumarate:CoA ligase, and stilbene synthase, was reconstructed, produced stilbenes in high yields: resveratrol from tyrosine and pinosylvin from phenylalanine. To incorporate a stilbene methyltransferase gene into this E. coli system, cDNA of Os08g06100 in Oryza sativa was expressed and its O‐methylating activity toward stilbenes was confirmed. Incorporation of the pinosylvin methyltransferase (OsPMT) gene into the pathway established in E. coli led to production of mono‐ and di‐methylated stilbenes. Furthermore, the OsPMT gene turned out to be useful in production of unnatural stilbene methyl ethers due to its rather relaxed substrate specificity; various carboxylic acids supplemented as precursors, such as p‐fluorocinnamic acid, 3‐(2‐furyl)acrylic acid, 3‐(2‐thienyl)acrylic acid, and 3‐(3‐pyridyl)acrylic acid, to the E. coli system carrying the steps of 4‐coumarate:CoA ligase, stilbene synthase, and OsPMT were converted to stilbene dimethyl ethers with the corresponding carboxylic moiety.
A novel antibiotic free plasmid selection system: Advances in safe and efficient DNA therapy
Authors: Mairhofer Jürgen , Pfaffenzeller Irene , Merz David , Grabherr Reingard
Published: September 2007

The presence of antibiotic resistance genes in the delivered plasmids is one of the drawbacks of modern gene therapy and DNA vaccine applications. Here, we describe a strategy that allows for plasmid selection in bacterial hosts, without the requirement of any selection marker. Several bacterial strains were modified, so that the plasmid's replicational inhibitor RNA I could suppress the translation of a growth essential gene by RNA‐RNA antisense reaction. An essential gene (murA) was modified such that a repressor protein (tetR) would hamper its expression. Only in the presence of plasmid and, hence, RNA I, was tetR turned down and murA expressed. Different commercially available plasmids could be selected by various modified Escherichia coli strains. We further designed a minimalistic plasmid devoid of any selection marker. All of the clones (n=6) examined, when the modified strain JM109‐murselect was used for selection, contained plasmids. Thus, we have designed bacterial host strains that for the first time serve to select and maintain plasmids without the use of any selection marker or other additional sequence on the plasmid. Consequently, such plasmids may not only be safer, but due to their decreased size, advantages for the manufacturer and higher transfection efficiencies are anticipated.
Structure–function relationships in RNA and RNP enzymes: Recent advances
Authors: Hoogstraten Charles G. , Sumita Minako
Published: September 2007

The structural biology of ribozymes and ribonucleoprotein (RNP) enzymes is now sufficiently advanced that a true dialogue between structural and functional studies is possible. In this review, we consider three important systems in which an integration of structural and biochemical data has recently led to major advances in mechanistic understanding. In the hammerhead ribozyme, application‐driven biochemical studies led to the discovery of a key structural interaction that had been omitted from previously‐studied constructs. A new crystal structure of the resulting, tertiary‐stabilized hammerhead has resolved a remarkable number of longstanding paradoxes in the structure–function relationship of this ribozyme. In the Group I intron ribozyme, a flurry of high‐resolution structures has largely confirmed, but in some cases refined or challenged, a detailed model of a metalloenzyme active site that had previously been derived by meticulous quantitative metal ion rescue experiments. Finally, for the peptidyl transferase center of the ribosome, recent biochemical and chemical results motivated by the pioneering crystal structures have suggested a picture of a catalytic mechanism dominated by proximity and orientation effects and substrate‐assisted catalysis. These results refocus attention on catalysis as a property of the integrated RNP machinery as a whole, as opposed to a narrow concern with the RNA functional groups in immediate contact with the reactive center. © 2007 Wiley Periodicals, Inc. Biopolymers 87: 317–328, 2007.

This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Evidence for the 310‐helical structure of peptides based on antAib, a fluorophoric, anthracene‐fused, 1‐aminocyclopentane‐1‐carboxylic acid
Authors: Wright Karen , Lohier Jean‐François , Wakselman Michel , Mazaleyrat Jean‐Paul , Peggion Cristina , Formaggio Fernando , Toniolo Claudio
Published: September 2007

Peptides based on 2‐amino‐2,3‐dihydro‐1H‐cyclopenta[b]anthracene‐2‐carboxylic acid (antAib), a fluorescent, achiral, α‐amino acid belonging to the class of C→C cyclized, Cα,α‐disubstituted glycines, combined with L‐Ala, up to the hexamer level, were synthesized by solution methods and chemically characterized. A conformational analysis by FTIR absorption and NMR techniques suggests that the highest oligomers of this series tend to fold into β‐turns/310‐helices. The UV absorption, CD, and fluorescence properties of these antAib/L‐Ala model peptides are also described. © 2007 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 88: 797–806, 2007.

This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Demonstration of REBASE‐assisted restriction mapping to determine the recognition site of unknown restriction endonucleases
Authors: Parashar Vijay , Capalash Neena , Sharma Prince
Published: September 2007

An important step in the characterization of a new restriction enzyme involves determination of its recognition site. Comparison of its DNA substrate digestion fragment patterns with those obtained using enzymes of known specificity indicates whether the enzyme recognizes a novel sequence or is an isoschizomer of already existing prototype. REBASE (Restriction Enzyme dataBASE: http://www.neb.com/rebase)‐assisted restriction mapping is described in this paper for a rare cutter [TspMI (REBASE No. 7191)] and a frequent cutter [BflI (REBASE No. 4910)] as a practical exercise for undergraduate students to understand how to determine recognition sequence of a REase.
Gel electrophoresis
Authors: Tan Timothy Ter Ming , Tan Zong Ying , Tan Wei Liang , Lee Peng Foo Peter
Published: September 2007

The aim of this project is to develop a simple system for the teaching and demonstration of DNA gel electrophoresis. DNA gel electrophoresis requires the use of specialized apparatus, toxic reagents, expensive agarose gel, and DNA samples, as well as a considerable amount of valuable classroom time to complete. A systematic evaluation of suitable alternative materials and components for the simulation of DNA gel electrophoresis was undertaken. A tried and tested set of combinations is presented here for educators to use in hands‐on classroom teaching, which does not require DNA, agarose, or Tris–borate–EDTA buffer. The use of common biological stains in place of DNA samples, agar–agar‐based gels, and weak electrolyte solutions provides a simple, inexpensive, and highly reproducible system that is adaptable to instructional needs. The migration of multicolored bands during electrophoresis provides an intuitive, compelling demonstration of the concept of electrophoresis.
Screening of lactic acid bacteria for bacteriocins by microbiological and PCR methods
Authors: Suwanjinda Duongdearn , Eames Chris , Panbangred Watanalai
Published: September 2007

We describe a practical laboratory designed for third‐year undergraduate students of Biotechnology as part of a Microbial Physiology and Genetics course. It comprises a five‐session laboratory module to screen foods for lactic acid bacteria (LAB)1 and to test isolated LAB for the presence of bacteriocins. Traditional Thai fermented foods are first screened for bacteriocin‐producing LAB using microbiological methods. This is followed by a simple and rapid DNA extraction and by a multiplex polymerase chain reaction (PCR) using three pairs of specific primers to test for the presence or absence of various bacteriocin genes in the isolated LAB. PCR amplicons of 332, 412, and 608 bp indicate the presence of pediocin, enterocin, and nisin genes, respectively, whereas no amplicon band indicates the absence of these bacteriocins. The laboratory provides the students with experience in the use of microbiological and multiplex PCR methods and shows how the molecular biology techniques can be related to their daily lives. The module could easily be adapted to the study of fermented foods from other countries.
Teaching lactose metabolism
Authors: Monti‐Hughes Andrea , Alonso Manuel , Garófalo Judith , Burgos Hilda Isabel , Stella Carlos Alberto
Published: September 2007

We developed an experimental didactic proposal to teach both carbohydrate metabolism and lactose intolerance as the disease related to that metabolism. Therefore, we implemented an empirical strategy consisting of inexpensive and nontoxic components for which students do not need to know any of the laboratory techniques. The fact that students were able to discuss their own results obtained from the experiments performed in their classroom gave them an additional motivation to learn the subject.
Blackboard electrophoresis
Authors: Costa M. J.
Published: September 2007

Undergraduates with little training on molecular biology may find the technical level of the typical introductory restriction laboratory too challenging and have problems with mastering the underlying concepts and processes. Blackboard electrophoresis is an active learning exercise, which focuses student attention on the sequences and principles of DNA restriction. Students convert short strings of letters of A, C, G, and Ts into blackboard electrophoresis profiles analogous to gel electrophoresis of restriction digests. Students work in teams to i) invent short strings of letters representing polynucleotides; ii) identify and count the number of specific restriction sequences in each string; iii) fractionate the strings in restriction fragments and count their size; and iv) predict blackboard electrophoretic patterns in which fragments are represented by sizes. The exercise is inexpensive, since it does not require laboratory equipment or supplies and accommodates a plethora of introductory contexts that can be explored to bring in relevance to students. The exercise has been used with high school and university audiences with very positive outcomes. Blackboard electrophoresis is a valuable complement or alternative to other instructional approaches to teach restriction analysis and DNA diversity.
Investigation of the properties of wild type and mutant alkaline phosphatase variants: A laboratory project linking genotype and phenotype
Authors: Howitt Susan M.
Published: September 2007

An understanding of the link between genotype and phenotype is essential for biology students. A 3‐wk laboratory project aimed at demonstrating this link and introducing early year students to some aspects of the research process is described. Students investigate the properties of wild type and mutant variants of alkaline phosphatase using the techniques of both biochemistry and molecular biology. Changes in enzyme activity are correlated with the changes in DNA sequence that introduce restriction enzyme sites. Mutants are also used to analyze the regulation of phoA gene expression. The application of different techniques to the same experimental system helps students to integrate information from different parts of the course.