bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigation of central versus peripheral effects of estradiol in ovariectomized mice
Authors: Andersson Niklas , Islander Ulrika , Egecioglu Emil , Löf Elin , Swanson Charlotte , Movérare-Skrtic Sofia , Sjögren Klara , Lindberg Marie K , Carlsten Hans , Ohlsson Claes
Published: November 2005

It is generally believed that estrogens exert their bone sparing effects directly on the cells within the bone compartment. The aim of the present study was to investigate if central mechanisms might be involved in the bone sparing effect of estrogens. The dose–response of central (i.c.v) 17β-estradiol (E2) administration was compared with that of peripheral (s.c.) administration in ovariectomized (ovx) mice. The dose–response curves for central and peripheral E2 administration did not differ for any of the studied estrogen-responsive tissues, indicating that these effects were mainly peripheral. In addition, ovx mice were treated with E2 and/or the peripheral estrogen receptor antagonist ICI 182,780. ICI 182,780 attenuated most of the estrogenic response regarding uterus weight, retroperitoneal fat weight, cortical BMC and trabecular bone mineral content (P<0.05). These findings support the notion that the primary target tissue that mediates the effect of E2 on bone is peripheral and not central.
Responses induced by arginine-vasopressin injection in the plasma concentrations of adrenocorticotropic hormone, cortisol, growth hormone and metabolites around weaning time in goats
Authors: Katoh K , Yoshida M , Kobayashi Y , Onodera M , Kogusa K , Obara Y
Published: November 2005

In order to assess the biological significance of weaning and water deprivation on the control of plasma concentrations of adrenocorticotropic hormone (ACTH), cortisol, growth hormone (GH) and metabolites in response to stimulation with arginine-vasopressin (AVP) and corticotropin-releasing hormone (CRH), we carried out three experiments in which male goats before and after weaning were intravenously injected with AVP or CRH alone, or in combination with each other. In experiment 1, 17-week-old (post-weaning) goats were intravenously injected with AVP or CRH alone at the doses of 0.1, 0.3 and 1.0 nmol/kg body weight (BW). The AVP injection significantly and dose dependently increased plasma levels of ACTH, cortisol, GH and metabolites, whereas the injection with CRH did not cause significant increases in the levels of these parameters. In experiment 2, 4-week-old (pre-weaning) and 13-week-old (post-weaning) goats were injected with either AVP or CRH alone, followed by a combined injection of both secretagogues at a dose of 0.3 nmol/kg BW. Although the basal levels of the hormones and metabolites, with the exception of glucose, were greater in the 4-week-old goats, the hormone responses induced by stimulation with AVP were weaker than those induced in 13-week-old goats. Additionally, there were no responses in any hormone patterns to CRH stimulation in 4-week-old goats. In experiment 3, 13-week-old goats were injected with CRH alone followed by injection with AVP for two consecutive days of water deprivation. The animals were subjected to withdrawal of up to 20% of the total blood volume and water deprivation for up to 28 h. However, no significant differences in plasma ACTH, cortisol or GH levels were observed between days 1 and 2. Based on these results, we concluded that: (1) AVP is a more potent stimulant than CRH in terms of its ability to induce increases in plasma levels of ACTH, cortisol and GH; (2) the role of AVP as a secretagogue of hypothalamus–pituitary–adrenal hormones is strengthened, whereas the ineffective role of CRH remains unaltered, by weaning; (3) acute stress such as massive withdrawal of blood volume and subjection to water deprivation may not be sufficient burdens to alter stress-related hormone levels in young goats.
A novel mechanism in control of human pigmentation by β-melanocyte-stimulating hormone and 7-tetrahydrobiopterin
Authors: Spencer Jennifer D , Chavan Bhaven , Marles Lee K , Kauser Sobia , Rokos Hartmut , Schallreuter Karin U
Published: November 2005

The human skin holds the full machinery for pro-opiomelanocortin processing. The α-melanocyte-stimulating hormone (α-MSH)/melanocortin-1-receptor cascade has been implicated as a major player via the cAMP signal in the control of melanogenesis. Only very recently the β-endorphin/μ-opiate receptor signal has been added to the list of regulators of melanocyte dendricity and melanin formation. In this context it was reported that (6R)-l-erythro-5,6,7,8-tetrahydrobiopterin (6BH4) can act as an allosteric inhibitor of tyrosinase, the key enzyme in melanogenesis, and this inhibition is reversible by both α- and β-MSH. It was also shown earlier that 7BH4, the isomer of 6BH4, is twice as active in this inhibition reaction. However, as yet it is not known whether 7BH4 is indeed present in loco in the melanosome. We here provide evidence that this isomer is present in this organelle in a concentration range up to 50 × 10−6 M. Determination of β-MSH in melanosomal extracts yielded 10 pg/mg protein. Moreover, we demonstrate reactivation of the 7BH4/tyrosinase inhibitor complex by β-MSH, whereas α-MSH failed to do so. Furthermore, we show intra-melanosomal l-dopa formation from dopachrome by 7BH4 in a concentration range up to 134 × 10−6 M. Based on these results, we propose a new receptor-independent mechanism in the control of tyrosinase/melanogenesis by β-MSH and the pterin 7BH4.
Protective effect of testosterone on early apoptotic damage induced by streptozotocin in rat pancreas
Authors: Morimoto S , Mendoza-Rodríguez C A , Hiriart M , Larrieta M E , Vital P , Cerbón M A
Published: November 2005

Beta-cell apoptosis is responsible for the development of insulin-dependent diabetes mellitus in the streptozotocin (STZ) rat model. It has been demonstrated that steroid hormones possess antioxidant and protective antiapoptotic effects in many tissues. The aim of the present study was to investigate the early apoptotic damage induced by STZ in rat pancreas, and the effect of testosterone in preventing apoptosis of pancreatic β cells. Intact and castrated adult male Wistar rats were subjected to a unique injection of STZ 60 mg/kg (body weight) in citrate buffer, and the kinetics of apoptosis in β cells was assessed. Insulin and glucose were measured by RIA and a glucometer respectively, and in pancreatic tissue by immunohistochemistry. At 6 h after STZ injection, a marked increase in apoptotic β cells was detected; however, glucose and insulin serum levels were not significantly different from the controls. The castrated animals presented higher percentages of apoptotic β cells (65.75 ± 5.42%) than intact males (20.6 ± 4.38%) and castrated, testosterone-substituted males (30.66 ± 1.38%). The decrease in apoptotic β cells induced by testosterone was reversed by the antiandrogen flutamide (67.69 ± 3.45%). The overall results indicate that early apoptotic damage produced by STZ in castrated animals was reversed by testosterone, suggesting that this hormone exerts a natural protective effect in rat pancreas. This effect could help to explain some sexual differences in diabetes mellitus incidence in man, reinforcing the idea that new approaches in steroid hormone therapies should be considered for treatment of this disease.
Up-regulation of rat myometrial phospholipases Cβ1 and Cβ3 correlates with increased term sensitivity to carbachol and oxytocin
Authors: Houdeau E , Lévy A , Mhaouty-Kodja S
Published: November 2005

In the present study, we compared rat uterine contractility and myometrial inositol phosphate (InsP) production in response to activation of muscarinic and oxytocin receptors during pregnancy and at term. The level of myometrial phospholipase (PL) Cβ was also determined by Western blotting at different stages of pregnancy and following administration of oestradiol, progesterone or vehicle. The results showed an increased potency of carbachol (CCh), a cholinergic muscarinic agonist, and oxytocin (OT) to enhance myometrial InsP production at term. This correlated with an increased potency of both agonists to induce contraction of the circular but not the longitudinal muscle. For both InsP production and contractile activity, the maximal response of CCh was unaltered, while that of OT was significantly increased. Interestingly, the increased responsiveness to CCh and OT was associated with an up-regulation of PLCβ1 and PLCβ3 enzymes. Such regulation is under the control of oestradiol since administration of this steroid to pregnant rats increased the amount of both enzymes by 200–260%. In contrast, progesterone administration was without effect. The present study presents the first evidence that the expression of rat myometrial PLCβ1 and PLCβ3 is under the positive control of oestradiol. This could participate in the enhancement of myometrial InsP accumulation and uterine contraction at term in response to CCh and OT. Based on contraction studies, we also propose that the longitudinal and circular uterine muscles differ in the regulation of the PLC pathway during pregnancy.
Transthyretin is not necessary for thyroid hormone metabolism in conditions of increased hormone demand
Authors: Sousa J C , de Escobar G Morreale , Oliveira P , Saraiva M J , Palha J A
Published: November 2005

Thyroid hormones circulate in blood mainly bound to plasma proteins. Transthyretin is the major thyroxine plasma carrier in mice. Studies in transthyretin-null mice revealed that the absence of transthyretin results in euthyroid hypothyroxinemia and normal thyroid hormone tissue distribution, with the exception of the choroid plexus in the brain. Therefore, transthyretin does not influence normal thyroid hormone homeostasis under standard laboratory conditions. To investigate if transthyretin has a buffer/storage role we challenged transthyretin-null and wild-type mice with conditions of increased hormone demand: (i) exposure to cold, which elicits thermogenesis, a process that requires thyroid hormones; and (ii) thyroidectomy, which abolishes thyroid hormone synthesis and secretion and induces severe hypothyroidism. Transthyretin-null mice responded as the wild-type both to changes induced by stressful events, namely in body weight, food intake and thyroid hormone tissue content, and in the mRNA levels of genes whose expression is altered in such conditions. These results clearly exclude a role for transthyretin in thyroid hormone homeostasis even under conditions of increased hormone demand.
Streptozotocin (STZ) mediates acute upregulation of serum and pancreatic osteopontin (OPN): a novel islet-protective effect of OPN through inhibition of STZ-induced nitric oxide production
Authors: Katakam A K , Chipitsyna G , Gong Q , Vancha A R , Gabbeta J , Arafat H A
Published: November 2005

Osteopontin (OPN) is a secreted acidic phosphoprotein that binds to a cell-surface integrin-binding motif and is involved in many inflammatory and immune-modulating disorders. There is compelling evidence that soluble OPN can in a variety of situations help cells survive an otherwise lethal insult. In this study we show that OPN is localized in the rat pancreatic islets and ducts. Staining of pancreatic serial sections with islet hormone antibodies showed that all islet cells express OPN. Rats treated with a single dose of streptozotocin (STZ; 50 mg/kg) showed acute upregulation of serum OPN levels and pancreatic OPN mRNA and protein. Serum OPN dropped by the end of day 7 but was still higher than prediabetic levels. Pancreatic mRNA and protein showed a similar pattern. Twenty-four hours after STZ injection, the intensified OPN expression was localized towards the periphery of the islets and surrounded the remaining insulin-positive cells. To explore the significance of OPN acute upregulation, freshly isolated islets were pretreated with OPN (0.15–15 nM) before addition of STZ. OPN significantly reduced the STZ-induced NO levels in the islets through an Arg-Gly-Asp (RGD)-dependent reduction of inducible NO synthase (iNOS) mRNA levels. Addition of OPN to freshly isolated mildly diabetic islets (blood glucose <300 mg/dl) significantly improved their glucose-stimulated insulin secretion and reduced their NO levels. Next we investigated the regulation of OPN in β-cells. When STZ (5 mM) was added to the β-cell line RINm5F it significantly increased OPN mRNA levels within 6 h. To distinguish between the effect of STZ and high glucose on OPN transcription, RINm5F cells were transfected with luciferase-labeled rat OPN promoter and treated with STZ (0.05–5 mM) or with glucose (5–25 mM). STZ induced upregulation of OPN promoter activity within 3 h, while high glucose induced upregulation of OPN promoter activity after 48 h. Our data introduce OPN as a novel islet protein that is differentially regulated by STZ and glucose in the islets. OPN initial upregulation after diabetes induction was probably due to STZ-induced toxicity, while maintenance of the high OPN levels might be due to hyperglycemia. The acute induction of OPN after STZ-induced diabetes might represent an endogenous mechanism to protect the islets against STZ-induced cytotoxicity, partly via an RGD-dependent NO regulatory mechanism.
Time Domain Reflectometry Range of Accuracy for High Surface Area Soils
Authors: Logsdon Sally
Published: November 2005

Time domain reflectometry (TDR) is commonly used to determine water content. Many laboratory studies have shown accurate water determination across a wide range of soils, often with a unified calibration equation. Recent data has shown a strong temperature influence on some TDR data. The purpose of this study was to calibrate TDR for water content under both laboratory and field conditions for Mollisols. TDR waveguides and thermocouples were installed horizontally into the sides of pits at four sites and 9 or 10 depth positions on a 5% slope. Neutron access tubes were installed within 3.3 m of the TDR sites. After the field study, soil was collected around the waveguides and repacked into columns for laboratory calibration. The columns were progressively wetted and then dried over a few months. At each water content and at two or three temperatures, the waveforms, bulk electrical conductivity, and square root of apparent dielectric εa1/2 were saved for the laboratory data, but memory limitations prevented saving waveforms from the field data. Much of the field calibration data were shifted to higher values for εa1/2 than for the laboratory data, apparently due to problems with internal waveform analysis. High bulk electrical conductivities (up to 0.13 S m−1) were apparent for some of the sites and depths even though these are not saline soils. For the laboratory data, adding a temperature term to the calibration equation reduced the root mean square error (378 data points) from 0.54 to 0.34 m3 m−3, and for the field data (939 points) reduced it from 0.78 to 0.54 m3 m−3
Evaluation of a Capacitance Probe Frequency Response Model Accounting for Bulk Electrical Conductivity: Comparison with TDR and Network Analyzer Measurements
Authors: Robinson D. A. , Kelleners T. J. , Cooper J. D. , Gardner C. M. K. , Wilson P. , Lebron I. , Logsdon S.
Published: November 2005

Soils ranging in texture from sand to clay were used to compare permittivity measurements made using a Surface Capacitance Insertion Probe (SCIP) and time domain reflectometer (TDR). Measurements were made using the same electrodes embedded in each soil, making the measurements directly comparable. The objective of the work was to test a model describing the frequency response of the SCIP to both permittivity and electrode conductance, and to compare results with TDR and network analyzer measurements. The model was tested using liquids of known permittivity and in saline, dielectric solutions. Surface Capacitance Insertion Probe and TDR determined permittivity values are similar for sandy soils but diverge for loam and clay soils. Using Topp's values as a reference, the SCIP‐determined permittivities for loams and clays lay close to the curve at water contents <0.25 m3 m−3, then often rose above the curve with increasing water content. Surface Capacitance Insertion Probe permittivity correction, using electrical conductivity (EC) measured at 1 kHz, corrected the results in sands reasonably well but not enough in loams and clays for reliable calibration. We propose three possible reasons for the higher than expected permittivity values observed using the SCIP: (i) higher than expected real permittivity created by dielectric dispersion, (ii) a large contribution of the imaginary permittivity due to relaxation processes assumed to be negligible, and (iii) poor model prediction of permittivity due to excessive damping of the oscillator circuit with high EC and dielectric losses. Results from network analyzer measurements for one of the clay soils were used to aid data interpretation. The TDR measurements were much more consistent, producing apparent relative permittivity values below those of the Topp curve for the finer textured soils.
Comparing Heat‐Pulse and Time Domain Reflectometry Soil Water Contents from Thermo‐Time Domain Reflectometry Probes
Authors: Ren Tusheng , Ju Zhaoqiang , Gong Yuanshi , Horton Robert
Published: November 2005

The thermo‐time domain reflectometry (thermo‐TDR) technique provides a valuable tool for monitoring coupled heat, water, and chemical transport in the vadose zone. This study evaluated the heat‐pulse and the TDR methods for soil water content determination using the thermo‐TDR probe. Laboratory measurements were conducted on repacked and undisturbed soil columns of different bulk densities and water contents. For the heat‐pulse method, the bulk specific heats of soil solids were determined using the thermo‐TDR probe on oven‐dried soil samples, and volumetric soil water content (θHP) was estimated from the heat capacity and water content relationship. For TDR measurements, the first reflection point on the waveform was determined by shorting the probe in air and the apparent probe length was determined from calibration in distilled water. The Topp equation was applied to convert the apparent relative permittivity to soil water content (θTDR). The thermo‐TDR probe is ideal for making the comparison between the heat pulse and TDR methods because the probe makes both measurements on nearly the same soil volume (approximate radius of 14 mm about the central heater for θHPand approximate radius of 11 mm about the central cylinder for θTDR). Experimental results on eight soils showed that both TDR and heat‐pulse methods gave reliable soil water content data for repacked and undisturbed soil. Comparing with gravimetrically measured volumetric water content, the root mean square error (RMSE) of θTDRmeasurements was 0.023 m3m−3for repacked soils and 0.018 m3m−3for undisturbed soils. The RMSE of θHPmeasurements was 0.022 m3m−3for repacked soils and 0.021 m3m−3for undisturbed soils. The relatively large RMSE of the TDR measurements is attributed to the relatively short length (4‐cm) of the thermo‐TDR probe. The TDR method showed less sensitivity to spatial soil variability than did the heat‐pulse method. The heat‐pulse technique seemed better suited than TDR for water content measurements on soils with relatively high organic matter content.
Numerical Modeling of GPR to Determine the Direct Ground Wave Sampling Depth
Authors: Galagedara L. W. , Redman J. D. , Parkin G. W. , Annan A. P. , Endres A. L.
Published: November 2005

The direct ground wave method of ground penetrating radar (GPR) has been suggested as a cost‐effective means of estimating field‐scale soil moisture variability for irrigation and water resource management. Knowing the sampling depth of the GPR direct ground wave (GW) is very important because it is critical to know the depth when measuring soil moisture in the field. Few studies have addressed this particular aspect of the GPR method. Numerical simulation of GPR electromagnetic waves using GPRMAX2D was performed for two‐layer soil models to estimate the direct GW sampling depth for soil moisture. Dry over wet soil layers and wet over dry soil layers were modeled by using appropriate dielectric permittivity values for each layer. Model runs were conducted for a gradually decreasing upper layer thickness. The GW sampling depth was estimated as the upper dry or wet layer thickness when the modeled GW velocity decreased or increased by 5% as affected by the lower wet or dry layer, respectively. It was found from this modeling exercise that the GW sampling depth changed with the antenna frequency as well as the moisture content of the upper layer. A very strong linear relationship (r2 = 0.98) was found between the wavelength and the sampling depth of the GPR direct GW.
Monitoring Soil Water Content Profiles with a Commercial TDR System: Comparative Field Tests and Laboratory Calibration
Authors: Laurent Jean‐Paul , Ruelle Pierre , Delage Laurent , Zaïri Abdelaziz , Nouna Béchir Ben , Adjmi Tarek
Published: November 2005

The TRIME‐FM3 (Imko GmbH, Ettlingen, Germany) time domain reflectometry (TDR) handheld instrument combined with the T3 access tube probe is a commercial soil water content (SWC) profiling system. The main purpose of this study was to evaluate its performance under real field conditions. The evaluation was performed on four sites in Tunisia and France where several measuring campaigns were organized between 2000 and 2002. Reference SWC measurements were also taken systematically. Direct comparisons of the corresponding data showed that a linear correction was generally sufficient to locally calibrate the TRIME (time domain reflectometry with intelligent microelements) measurements. Nevertheless, because of the influence of other interfering factors, a significant error (0.01 < RMSE < 0.07) still remained after this correction. As a possible alternative, the internal standard TRIME‐FM3 calibration was also examined. On the basis of our large set of data, new calibration coefficients were derived to convert the TRIME‐FM3 internal measurement (a so‐called pseudo transit time) into the displayed SWC. However, its general validity should be tested with other independent data. Several laboratory experiments were also performed: TRIME‐tube measurements were taken on reference media and on a 10‐L sample of soil that was monitored twice during drying from total water saturation to an equilibrium dry state. It was thus possible to quantify the sensitivity of the TRIME‐tube measurement to the surrounding medium permittivity. An empirical formula was also established for inferring the soil permittivity from the TRIME‐tube measured pseudo transit time.
Time Domain Reflectometry Laboratory Calibration in Travel Time, Bulk Electrical Conductivity, and Effective Frequency
Authors: Evett Steven R. , Tolk Judy A. , Howell Terry A.
Published: November 2005

Accurate soil water content measurements to considerable depth are required for investigations of crop water use, water use efficiency, irrigation efficiency, and the hydraulic properties of soils. Although the soil moisture neutron probe has served this need well, it cannot be used unattended. Newer methods, which respond to the electrical properties of soils, typically allow data logging and unattended operation, but with uncertain precision, accuracy, and volume of sensitivity. In laboratory columns of three soils, we calibrated a conventional time domain reflectometry (TDR) system for use as a reference system for a companion study of water content sensors that are used in access tubes. Measurements were made before, during, and after wetting to saturation in triplicate repacked columns of three soils: (i) a silty clay loam (30% clay, 53% silt), (ii) a clay (48% clay, 39% silt), and (iii) a calcic clay loam (35% clay, 40% silt) containing 50% CaCO3. Each 75‐cm‐deep, 55‐cm‐diameter column was weighed continuously to 50‐g precision on a platform scale. Conventional TDR measurements of water content and thermocouple measurements of temperature were made at eight depths in each column every 30 min. Accuracy of the TDR system was judged by the root mean squared difference (RMSD) between column mean water contents determined by mass balance and those determined using the Topp equation as a standard calibration. Smaller values of the RMSD metric indicated more accurate standard calibration. Although the TDR system exhibited RMSD <0.03 m3 m−3 using the Topp equation, there were differences in accuracy between the three soils, and there was some temperature dependency at the saturated end, although not at the dry end. This paralleled the temperature dependency of the soil bulk electrical conductivity (BEC). Incorporation of bulk electrical conductivity and effective frequency of the TDR measurement into the calibration model reduced the calibration RMSE to <0.01 m3 m−3 and practically eliminated temperature effects. Because the temperature effects on the TDR measurement are embedded in the BEC and effective frequency, a measurement of temperature is not needed to apply the calibration to these soils.
The Impact of Curricular Interventions on Intended Second Year Re-Enrollment
Authors: Keup Jennifer R.
Published: November 2005

Utilizing data from the national administration of a Cooperative Institutional Research Program (CIRP) baseline and follow-up survey of the first-year experience during the 2002–2003 academic year, this study explores the relationship between three curricular interventions—first-year seminars, service-learning, and learning communities—and the longitudinal process of first-to-second year retention. The findings from descriptive analyses showed that there are numerous positive relationships between these three interventions and integrative first-year experiences as defined by Tinto's (1987, 1993) longitudinal model of departure. Further, logistic regression suggests that service-learning courses have an indirect impact on the intent to re-enroll for a second year of college, while first-year seminars and learning communities may have an interactive relationship in their impact on the outcome measure.
Four and Six-Year Baccalaureate Degree Completion by Institutional Characteristics and Racial/Ethnic Groups
Authors: Oseguera Leticia
Published: November 2005

This study examined how institutional and environmental attributes of the undergraduate institution facilitate or impede African American, Asian American, Caucasian, and Mexican American students' baccalaureate degree attainment four and six years after college entry. The primary data source for this study was generated from a national survey of 63,640 first-time full-time freshman undergraduates at 303 colleges and universities. Variables that predict uniformly for all four groups include school grades (positive), on campus residence (positive), private control (positive), institutional size (negative), institutional selectivity (positive), and peer socioeconomic level (positive). Once these variables are controlled, standardized test scores add very little to the prediction of degree completion. Consistent with stated hypotheses, all five structural dimensions of the institution—mission, size, quality/selectivity, complexity/diversity, and wealth—affect degree completion.
Student Characteristics Related to Persistence for First-Year Community College Students
Authors: Hawley Tamela H. , Harris Tracy A.
Published: November 2005

This study analyzed student characteristics that impact persistence among first-year students attending a large, metropolitan community college. The Cooperative Institutional Research Program (CIRP) Freshmen Survey was administered to first-time students during orientation. Factor analysis was used to classify students' personality and behavioral characteristics and discriminant function analysis was used to predict retention or attrition. The discriminant model accurately predicted retention in 78.8% of the cases. Findings suggested that student characteristics impacting persistence can be classified into three categories: barriers, motivations and aspirations, and expectations. Among the strongest predictors of attrition were the number of developmental classes required, the intention to transfer to a four-year institution, and the expectation that English as a second language could be a problem for college students. Among the strongest predictors of persistence were being African American or Latino, cumulative GPA, and the length of time students plan to spend at the college. Recommendations are shared for how community college administration, faculty, and staff can work with students and the community to raise student expectations, motivation, and preparation long before they become first-year college students.
Inside Front Cover: Selective Construction of Supramolecular Nanotube Hosts with Cationic Inner Surfaces (Adv. Mater. 22/2005)
Authors: Kameta N. , Masuda M. , Minamikawa H. , Goutev N. V. , Rim J. A. , Jung J. H. , Shimizu T.
Published: November 2005

Selective construction of a supramolecular nanotube host with a cationic inner surface consisting of unsymmetrical bolaamphiphiles is reported on p. 2732 by Masuda, Shimizu, and co‐workers. The nanotube, shown schematically on the inside cover, has different inner and outer surfaces covered with amino and sugar functionalities, respectively, and is able to effectively encapsulate anionic nanomaterials, such as sulfate‐latex beads (see TEM image) and spherical proteins, in the cationic hollow cylinder without depending on capillary action.
Effect of Rare Earth Doping on the Catalytic Activity of Copper‐Containing Hydrotalcites in Phenol Hydroxylation
Authors: Chen Chunxia , Xu Chenghua , Feng Liangrong , Li Zijian , Suo Jishuan , Qiu Fali , Yang Yingchun
Published: November 2005

The copper‐containing hydrotalcites (Cu‐HTLcs) are synthesized under microwave irradiation, the effect of rare earth elements (RE) on the synthesis of Cu‐HTLcs, wherein RE stands for rare earth elements, e.g., La, Y, Sm and Ce, is also investigated in the present work. The hydrotalcite structure of the synthesized samples is verified by XRD and FT‐IR. The results of their catalytic performances in phenol hydroxylation show that the doped rare earth elements can promote the catalytic activity of Cu‐HTLcs, exhibiting a good trend as follows: La>Y>Sm>Ce. XPS results show that the Cu+ species are produced after the interaction of La‐Cu‐HTLcs with H2O2. Combining with the catalytic test results, we propose a new mechanism about the generation of HO. radicals in phenol hydroxylation, it is assumed that HO‐Cu+‐OH species are first formed by the reduction of HO‐Cu2+‐OH located in hydrotalcites in the presence of H2O2, and then react with H2O2 to give rise to HO. radicals.
Non‐Racemic Halohydrins via Biocatalytic Hydrogen‐Transfer Reduction of Halo‐Ketones and One‐Pot Cascade Reaction to Enantiopure Epoxides
Authors: Poessl Tina M. , Kosjek Birgit , Ellmer Ursula , Gruber Christian C. , Edegger Klaus , Faber Kurt , Hildebrandt Petra , Bornscheuer Uwe T. , Kroutil Wolfgang
Published: November 2005

Biocatalytic hydrogen‐transfer reduction of α‐chloro‐ketones furnished non‐racemic chlorohydrins by employing either Rhodococcus ruber as lyophilized cell catalyst or an alcohol dehydrogenase preparation from Pseudomonas fluorescens DSM 50106 (PF‐ADH). For all substrates investigated, Rhodococcus ruber gave strictly the “Prelog” product, whereas PF‐ADH showed scattered stereopreference. One possibility for a follow‐up reaction of halohydrins is the ring closure to the corresponding epoxide. A novel “one pot‐one step strategy” was employed to obtain the enantiopure epoxide from the α‐chloro‐ketone in a cascade like fashion at pH>12 involving biocatalytic hydrogen transfer reduction and in situ chemo‐catalyzed ring closure.
Stereoselective Hydrogenation of Folic Acid Dimethyl Ester Benzenesulfonate: A New Access to Optically Pure L‐Tetrahydrofolic Acid
Authors: Groehn Viola , Moser Rudolf , Pugin Benoît
Published: November 2005

Folic acid was converted to the corresponding dimethyl ester benzenesulfonate and stereoselectively hydrogenated in organic solvents. An extended screening with rhodium‐ and iridium‐diphosphine catalysts was performed. Under optimized conditions the asymmetric hydrogenation provided a solution of tetrahydrofolic acid dimethyl ester with up to 44% de. The de could be increased to 98% by fractional crystallization of L‐tetrahydrofolic acid dimethyl ester benzenesulfonate from the hydrogenation mixture. Hydrolysis of the ester afforded optically pure L‐tetrahydrofolic acid, which can be isolated or converted into its 5‐ or 10‐ or 5,10‐substituted derivatives.
Rhodium‐BisbenzodioxanPhos Complex‐Catalyzed Homogeneous Enantioselective Pauson–Khand‐Type Cyclization in Alcoholic Solvents
Authors: Kwong Fuk Yee , Lee Hang Wai , Qiu Liqin , Lam Wai Har , Li Yue‐Ming , Kwong Hoi Lun , Chan Albert S. C.
Published: November 2005

The chiral atropisomeric diphosphane ligand (S)‐BisbenzodioxanPhos was found to be highly effective in the co‐operative processeses of aldehyde decarbonylation and cascaded enantioselective Pauson–Khand‐type reactions. Various 1,6‐enynes were transformed to the corresponding bicyclic cyclopentenones in good yields and enantiomeric excesses (up to 96% ee). The attractive feature of this new Rh‐catalyzed homogeneous dual catalysis system is that the reaction can be performed in alcoholic solution.
Highly Enantioselective Iridium‐Catalyzed Hydrogenation of Quinoline Derivatives Using Chiral Phosphinite H8‐BINAPO
Authors: Lam Kim Hung , Xu Lijin , Feng Lichun , Fan Qing‐Hua , Lam Fuk Loi , Lo Wai‐hung , Chan Albert S. C.
Published: November 2005

The chiral diphosphinite H8‐BINAPO derived from H8‐BINOL has been used in the Ir‐catalyzed asymmetric hydrogenation of quinolines, and high enantioselectivity (up to 97% ee) was obtained. Immobilization of the iridium catalyst in poly(ethylene glycol) dimethyl ether (DMPEG) is also discussed. With DMPEG/hexane biphasic system, better enantioselectivities were obtained as compared to those observed in aprotic organic solvents.
A Na2WO4/H2WO4‐Based Highly Efficient Biphasic Catalyst towards Alkene Epoxidation, using Dihydrogen Peroxide as Oxidant
Authors: Maheswari Palanisamy Uma , de Hoog Paul , Hage Ronald , Gamez Patrick , Reedijk Jan
Published: November 2005

The tungsten‐containing biphasic catalytic system [Na2WO4/H2WO4/PTR/chloroacetic acid] effectively epoxidizes alkenes with 50% H2O2 as terminal oxidant, under organic solvent‐free conditions. The catalytic process is proposed to proceed via a dinuclear tungsten peroxo species with coordinated chloroacetic acid, as suggested by ESI‐MS measurements. The catalytic system is suggested to involve tungsten‐peroxo and/or peracetic acid type of epoxidation catalyzed by the tungsten(VI) in the presence of an organic acid and H2O2. The reaction conditions employed for various alkenes for epoxidation are mild compared to the earlier studies and result in high product selectivity and conversion rate.
Convenient Modular Syntheses of Fluorous Secondary Phosphines and Selected Derivatives
Authors: Emnet Charlotte , Tuba Róbert , Gladysz J. A.
Published: November 2005

Reactions of the fluorous primary phosphines Rfn(CH2)2PH2 [Rfn=(CF2)n−1CF3; n=6, 8, 10] and Rfn′CHCH2 [(n′=6, 8, 10) (1 : 1; THF, reflux) in the presence of AIBN give the title compounds [Rfn(CH2)2][Rfn′(CH2)2]PH [n/n′=6/6 (4, 55%), 8/8 (5, 58%), 10/10 (6, 53%), 8/6 (7, 52%), 10/8 (8, 51%)] as low‐melting white solids on up to 10‐g scales. The chiral tertiary phosphine [Rf6(CH2)2][Rf8(CH2)2][Rf10(CH2)2]P (9) is similarly prepared from 7 and Rf10CHCH2 in the presence of VAZO (neat, 100 °C; 67%). The reaction of 5 and THF⋅BH3 yields the phosphine borane 5⋅BH3 (95%). Additions of triphosgene [(CCl3O)2CO] to 5 or Rf8(CH2)2PH2 give [Rf8(CH2)2]2PCl or Rf8(CH2)2PCl2, which are characterized in situ. The CF3C6F11/toluene partition coefficients of 4–9 increase with the number and lengths of the Rfn segments.
Synthesis of GDP‐Fucose on a Soluble Support: A Donor Substrate for the Fucosyltransferases
Authors: Daniellou Richard , Le Narvor Christine
Published: November 2005

The synthesis of GDP‐fucose on a poly(ethylene glycol)‐based soluble support is described. Our strategy relies on the attachment of the 6‐deoxy‐6‐thio‐L‐galactose onto the polymer via a thioether linkage , and its conversion to GDP‐fucose using established methods. We thus obtained GDP‐fucose bound to the polymer that was tested as an acceptor for the recombinant fucosyltranferase FucT‐III.
Reaction rates in ultrasonic emulsions of dense carbon dioxide and water
Authors: Timko Michael T. , Smith Kenneth A. , Danheiser Rick L. , Steinfeld Jeffrey I. , Tester Jefferson W.
Published: November 2005

Power ultrasound provides a surfactant‐free means of emulsifying dense near‐critical carbon dioxide and water. Droplet size distributions and volume fractions of the dispersed phases have been measured for acoustically formed emulsions. Hydrolysis rates were measured for a series of 7 benzoyl halides under both silent, phase‐separated conditions and for sonicated, emulsified conditions (30°C, 80 bar, 0.6 W/cm3, 20 kHz). Sonication always accelerated the overall hydrolysis rate, sometimes by as much as 200‐fold. Two physical models were developed to describe global kinetics: one for silent and one for sonicated conditions. The model for silent conditions agreed well with the available data set and suggested conditions under which reaction in the carbon dioxide phase (rather than the water phase) might become important. The model for sonicated conditions properly captured the trends in the data set and predicted the experimental results to within a factor of 2 in the worst case. Our analysis strongly suggests that ultrasound accelerates phase‐transfer reactions by increasing the water/carbon dioxide interfacial area. © 2005 American Institute of Chemical Engineers AIChE J, 2006
Unusual cerebrotendinous xanthomatosis with fronto‐temporal dementia phenotype
Authors: Guyant‐Maréchal Lucie , Verrips Aad , Girard Carole , Wevers Ron A. , Zijlstra Fokje , Sistermans Erik , Vera Pierre , Campion Dominique , Hannequin Didier
Published: November 2005

Cerebrotendinous xanthomatosis (CTX) is an autosomal recessive lipid storage disease caused by a deficiency of the mitochondrial enzyme 27‐sterol hydroxylase (CYP27). We report a 53‐year‐old man, with an unusual phenotype of CTX. He had xanthomas since adolescence. He had no mental retardation and developed at 44 years a progressive neuropsychiatric phenotype, suggestive of fronto‐temporal dementia according to clinical Neary criteria. Cataract and ataxia were absent. Cerebral MRI revealed diffuse hyperintense T2 abnormalities in the supratentorial white matter without cerebellar atrophy or lesions, while Technetium‐99m‐ECD brain SPECT revealed a severe cerebellar hypoperfusion. Serum cholestanol level was elevated with excessive urinary bile alcohols excretion. Mutation analysis revealed that he was compound heterozygous for two mutations in the CYP27A1 gene: 1016 C > T (exon 5) on one allele and a novel mutation, 1435C > G (exon 8) on the other allele. A follow‐up study was conducted to evaluate the effects of chenodeoxycholic acid (CDCA) and simvastatin treatment during 3 years. In spite of this treatment, cognitive functions declined but no other signs of neurological deterioration appeared. © 2005 Wiley‐Liss, Inc.
A family with Duane anomaly and distal limb abnormalities: A further family with the arthrogryposis‐ophthalmoplegia syndrome
Authors: McCann Emma , Fryer Alan E. , Newman William , Appleton Richard E. , Kohlhase Jürgen
Published: November 2005

A two‐generation family is reported in which three members have Duane anomaly and distal limb abnormalities. All three affected have photopic electroretinogram responses that are abnormal or at the lower limit of the normal range with normal scotopic responses. Two affected family members also have hearing loss. The likeliest diagnosis is the syndrome listed as “arthrogryposis‐ophthalmoplegia syndrome” on the London Dysmorphology Database or as “arthrogryposis with oculomotor limitation and electroretinal abnormalities” or “oculomelic aplasia” in OMIM [MIM 108145]. In view of the similarities with Okihiro syndrome, a search for mutations within the SALL4 gene was undertaken, but none were identified. © 2005 Wiley‐Liss, Inc.
An Xq22.3 duplication detected by comparative genomic hybridization microarray (Array‐CGH) defines a new locus (FGS5) for FG syndrome
Authors: Jehee Fernanda Sarquis , Rosenberg Carla , Krepischi‐Santos Ana Cristina , Kok Fernando , Knijnenburg Jeroen , Froyen Guy , Vianna‐Morgante Angela M. , Opitz John M. , Passos‐Bueno Maria Rita
Published: November 2005

FG syndrome is an X‐linked multiple congenital anomalies (MCA) syndrome. It has been mapped to four distinct loci FGS1‐4, through linkage analysis (Xq13, Xp22.3, and Xp11.4‐p11.3) and based on the breakpoints of an X chromosome inversion (Xq11:Xq28), but so far no gene has been identified. We describe a boy with FG syndrome who has an inherited duplication at band Xq22.3 detected by comparative genomic hybridization microarray (Array‐CGH). These duplication maps outside all four loci described so far for FG syndrome, representing therefore a new locus, which we propose to be called FGS5. MID2, a gene closely related to MID1, which is known to be mutated in Opitz G/BBB syndrome, maps within the duplicated segment of our patient. Since FG and Opitz G/BBB syndromes share many manifestations we considered MID2 a candidate gene for FG syndrome. We also discuss the involvement of other potential genes within the duplicated segment and its relationship with clinical symptoms of our patient, as well as the laboratory abnormalities found in his mother, a carrier of the duplication. © 2005 Wiley‐Liss, Inc.
Array‐based comparative genomic hybridization analysis of recurrent chromosome 15q rearrangements
Authors: Sahoo Trilochan , Shaw Chad A. , Young Andrew S. , Whitehouse Nathan L. , Schroer Richard J. , Stevenson Roger E. , Beaudet Arthur L.
Published: November 2005

Genomic rearrangements of chromosome 15q11‐q13 cause diverse phenotypes including autism, Prader–Willi syndrome (PWS), and Angelman syndrome (AS). This region is subject to genomic imprinting and characterized by complex combinations of low copy repeat elements. Prader–Willi and Angelman syndrome are caused primarily by 15q11‐13 deletions of paternal and maternal origin, respectively. Autism is seen with maternal, but not paternal, interstitial duplications. Isodicentric 15q, most often of maternal origin, is associated with a complex phenotype often including autistic features. Limitations of conventional cytogenetic tests preclude a detailed analysis in most patients with 15q rearrangements. We have developed a microarray for comparative genomic hybridization utilizing 106 genomic clones from chromosome 15q to characterize this region. The array accurately localized all breakpoints associated with gains or losses on 15q. The results confirmed the location of the common breakpoints associated with interstitial deletions and duplications. The majority of idic(15q) chromosomes are comprised of symmetrical arms with four copies of the breakpoint 1 to breakpoint 5 region. Patients with less common breakpoints that are not distinguished by routine cytogenetic methods were more accurately characterized by array analysis. This microarray provides a detailed characterization for chromosomal abnormalities involving 15q11‐q14 and is useful for more precise genotype–phenotype correlations for autism, PWS, AS, and idic(15) syndrome. © 2005 Wiley‐Liss, Inc.
Changes in hair morphology of mucopolysaccharidosis I patients treated with recombinant human α‐L‐iduronidase (laronidase, Aldurazyme)
Authors: Kloska Anna , Bohdanowicz Jerzy , Konopa Grażyna , Tylki‐Szymńska Anna , Jakóbkiewicz‐Banecka Joanna , Czartoryska Barbara , Liberek Anna , Węgrzyn Alicja , Węgrzyn Grzegorz
Published: November 2005

Mucopolysaccharidoses (MPS) are heritable, metabolic diseases caused by accumulation of mucopolysaccharides (glycosaminoglycans, GAGs) in lysosomes. This accumulation is due to a deficiency in one of several specific enzymes involved in the degradation of GAGs. MPS type I (MPS I) is caused by low or undetectable activity of α‐L‐iduronidase, an enzyme involved in removing the terminal iduronic acid residues from heparan and dermatan sulfate. Recently, an enzyme replacement therapy (ERT) for MPS I, based on administration of recombinant human α‐L‐iduronidase (laronidase, Aldurazyme), became available. The assessment of efficacy of ERT is especially important because MPS I is a highly variable and very rare disease, and the clinical trials involved relatively low number of patients. Among various significant clinical improvements during ERT, remarkable changes in hair morphology were noted. Detailed studies of hair samples from one patient, who did not have a hair cut from the beginning of ERT to the end of this study, and supported by results obtained for two other patients, revealed hair shaft structural abnormalities in MPS I hair. These hair abnormalities disappeared upon treatment with Aldurazyme. Although hair morphology is of limited clinical importance, the data suggest that changes in this parameter could be a useful, additional tool for a rapid, non‐invasive, preliminary assessment of ERT efficacy. © 2005 Wiley‐Liss, Inc.
Analysis of polymorphisms in AT‐rich domains of neuregulin 1 gene in schizophrenia
Authors: Lachman Herbert M. , Pedrosa Erika , Nolan Karen A. , Glass Max , Ye Kenny , Saito Takuya
Published: November 2005

Linkage analysis and association studies have pointed to neuregulin 1 (NRG1) as the prime candidate for 8p‐linked schizophrenia (SZ). However, so far, no specific functional alleles in the gene's exons, intron–exon junctions and promoters have been identified that are unequivocally associated with SZ. In this study, we analyzed several NRG1 polymorphisms that affect ATTT motifs and AT‐rich regions of the gene. We have previously identified a number of such polymorphisms in the promoters of other SZ and bipolar disorder (BD) candidate genes and found positive associations to several of them. In addition, allele specific differences in the binding of brain proteins have been found for many of the polymorphisms. A case control design was used to compare allele frequencies in Caucasian and African American patients with SZ and controls. In the African American group, a significant difference was found in the allele and genotype distribution for several of the markers and haplotype blocks located in the 5′‐ and 3′‐ends of the gene. The most significant result was obtained for rs6150532, an insertion/deletion variant in a conserved region of an intron that separates two small, alternatively spliced exons. Allele‐specific and developmental differences were detected in the binding of a brain protein using newborn rat pups when probes containing the two rs6150532 alleles were used in electromobility gel shift assays. There were no significant differences in allele or genotype distribution found for any of the markers in the Caucasian sample. Although the samples size is relatively small, the findings support a role for NRG1 in SZ in African Americans and suggest that polymorphic differences in regions of the gene that recognize AT‐binding proteins may be a factor in disease pathogenesis. © 2005 Wiley‐Liss, Inc.