bluuebunny/crossref_metadata_2025 huggingface dataset:
The Effect of Bed Rest on Bone Turnover in Young Women Hospitalized for Anorexia Nervosa: A Pilot Study
Authors: DiVasta Amy D. , Feldman Henry A. , Quach Ashley E. , Balestrino Maria , Gordon Catherine M.
Published: February 2009

Context: Malnourished adolescents with anorexia nervosa (AN) requiring medical hospitalization are at high risk for skeletal insults. Even short-term bed rest may further disrupt normal patterns of bone turnover.

Objective: The objective of the study was to determine the effect of relative immobilization on bone turnover in adolescents hospitalized for AN.

Design: This was a short-term observational study.

Setting: The study was conducted at a tertiary care pediatric hospital.

Study Participants: Twenty-eight adolescents with AN, aged 13–21 yr with a mean body mass index of 15.9 ± 1.8 kg/m2, were enrolled prospectively on admission.

Intervention: As per standard care, all subjects were placed on bed rest and graded nutritional therapy.

Main Outcome Measure: Markers of bone formation (bone specific alkaline phosphatase), turnover (osteocalcin), and bone resorption (urinary N-telopeptides NTx) were measured.

Results: During the 5 d of hospitalization, serum osteocalcin increased by 0.24 ± 0.1 ng/ml · d (P = 0.02). Urine N-telopeptides reached a nadir on d 3, declining −6.9 ± 2.8 nm bone collagen equivalent per millimole creatinine (P = 0.01) but returned to baseline by d 5 (P > 0.05). Bone-specific alkaline phosphatase exhibited a decline that was strongly age dependent, being highly significant for younger subjects only [age 14 yr: −0.42 ± 0.11 (P = 0.0002); age 18 yr: −0.03 ± 0.08 (P = 0.68)]. Age had no effect on other outcome measures.

Conclusion: Limitation of physical activity during hospitalization for patients with AN is associated with suppressed bone formation and resorption and an imbalance of bone turnover. Future interventional studies involving mechanical stimulation and/or weight-bearing activity are needed to determine whether medical protocols prescribing strict bed rest are appropriate.
Ancient animal ancestry for nuclear myosin
Authors: Hofmann Wilma A. , Richards Thomas A. , de Lanerolle Primal
Published: February 2009

The identification of nuclear myosin I (NMI) has raised the possibility that myosin might have had an early functional role in the eukaryotic nucleus. To investigate this possibility, we examined the molecular evolution of the vertebrate myosin-I proteins. We found that myosin I has undergone at least five duplication events in the common ancestor of the vertebrates (vertebrate-specific duplications), leading to nine myosin-I vertebrate gene families, followed by two additional myosin-I duplication events in the lineage leading to modern fish. This expansion suggests a large-scale adaptive radiation in myosin-I function in an early phase of vertebrate evolution. The branching order of the evolutionary tree suggests that the functional role of NMI predates this expansion. More specifically, in the tunicate Ciona intestinalis, we found a myosin-I protein that localizes to the nucleus, but that branches on phylogenetic trees before the duplication that led to vertebrate myosin IC and myosin IH. This relationship suggests that the common ancestor of these three proteins encoded a nuclear isoform and that the localization of myosin I to the nucleus predates the origin of the vertebrates. Thus, a functional role for NMI appears to have been present at an early stage of animal evolution prior to the rise of both myosin IC and the vertebrates, as NMI was present in the last common ancestor of vertebrates and tunicates.
Memo is a cofilin-interacting protein that influences PLCγ1 and cofilin activities, and is essential for maintaining directionality during ErbB2-induced tumor-cell migration
Authors: Meira Maria , Masson Régis , Stagljar Igor , Lienhard Susanne , Maurer Francisca , Boulay Anne , Hynes Nancy E.
Published: February 2009

Heregulin (HRG) activates ErbB2-ErbB3 heterodimers thereby stimulating many cellular responses, including motility. Memo and PLCγ1 interact with ErbB2 autophosphorylation sites and are essential for HRG-induced chemotaxis. By tracing HRG-stimulated cell migration in Dunn chambers, we found that Memo- or PLCγ1 knockdown (KD) strongly impairs cell directionality. Memo has no obvious enzymatic activity and was discovered via its ability to complex with ErbB2. Using the yeast two-hybrid approach to gain insight into Memo function, an interaction between Memo and cofilin, a regulator of actin dynamics, was uncovered. The interaction was confirmed in vitro using recombinant proteins and in vivo in co-immunoprecipitation experiments where Memo was detected in complexes with cofilin, ErbB2 and PLCγ1. Interestingly, in Memo KD cells, HRG-induced PLCγ1 phosphorylation was decreased, suggesting that Memo regulates PLCγ1 activation. Furthermore, HRG-induced recruitment of GFP-cofilin to lamellipodia is impaired in Memo and in PLCγ1 KD cells, suggesting that both proteins lie upstream of cofilin in models of ErbB2-driven tumor-cell migration. Finally, in vitro F-actin binding and depolymerization assays showed that Memo enhances cofilin depolymerizing and severing activity. In summary, these data indicate that Memo also regulates actin dynamics by interacting with cofilin and enhancing its function.
The BTB-MATH protein BATH-42 interacts with RIC-3 to regulate maturation of nicotinic acetylcholine receptors
Authors: Shteingauz Anna , Cohen Emiliano , Biala Yoav , Treinin Millet
Published: February 2009

RIC-3 is a member of a conserved family of proteins that affect nicotinic acetylcholine receptor maturation. In yeast and in vitro, BATH-42, a BTB- and MATH-domain-containing protein, interacts with RIC-3. BATH-42 is also known to interact with the CUL-3 ubiquitin ligase complex. Loss of BATH-42 function leads to increased RIC-3 expression and decreased activity of nicotinic acetylcholine receptors in Caenorhabditis elegans vulva muscles. Increased expression of RIC-3 is deleterious for activity and distribution of nicotinic acetylcholine receptors, and thus the effects of BATH-42 loss of function on RIC-3 expression explain the associated reduction in receptor activity. Overexpression of BATH-42 is also detrimental to nicotinic acetylcholine receptor function, leading to decreased pharyngeal pumping. This effect depends on the C-terminus of RIC-3 and on CUL-3. Thus, our work suggests that BATH-42 targets RIC-3 to degradation via CUL-3-mediated ubiquitylation. This demonstrates the importance of regulation of RIC-3 levels, and identifies a mechanism that protects cells from the deleterious effects of excess RIC-3.
SUMOylation regulates Kv2.1 and modulates pancreatic β-cell excitability
Authors: Dai Xiao-Qing , Kolic Jelena , Marchi Paolo , Sipione Simonetta , MacDonald Patrick E.
Published: February 2009

The covalent attachment of small ubiquitin-like modifier (SUMO) proteins regulates protein localization and function. SUMOylation has recently been shown to modulate ion-channel function; however, the extent to which this affects native currents and cellular excitability remains to be determined. The voltage-dependent K+ (Kv) channel Kv2.1 regulates pancreatic β-cell excitability and insulin secretion. We found that YFP-tagged SUMO1 (SUMO1-YFP) can be immunoprecipitated with Kv2.1 when these two proteins are coexpressed in HEK 293 cells. Furthermore, direct infusion of recombinant SUMO1 peptide or coexpression of SUMO1-YFP inhibited current through cloned Kv2.1 by 80% and 48%, respectively. Insulin-secreting cells express SUMO variants 1 and 3, and expression of the SUMO1-YFP in human β-cells or insulinoma cells inhibited native Kv currents (by 49% and 33%, respectively). Inhibition of the channel resulted from an acceleration of channel inactivation and an inhibition of recovery from inactivation, resulting in the widening of β-cell action potentials and a decreased firing frequency. Finally, these effects on channel function and excitability were augmented by the conjugating enzyme Ubc9 and rescued by the SUMO protease SENP1. Thus, protein SUMOylation can exert a strong inhibitory action on the voltage-dependent K+ channel Kv2.1 and can regulate cellular excitability in native β-cells.
The function of glutamatergic synapses is not perturbed by severe knockdown of 4.1N and 4.1G expression
Authors: Wozny Christian , Breustedt Jörg , Wolk Friederike , Varoqueaux Frédérique , Boretius Susann , Zivkovic Aleksandar R. , Neeb Antje , Frahm Jens , Schmitz Dietmar , Brose Nils , Ivanovic Aleksandra
Published: February 2009

AMPA-type glutamate receptors mediate fast excitatory synaptic transmission in the vertebrate brain. Their surface expression at synapses between neurons is regulated in an activity-dependent and activity-independent manner. The protein machinery that regulates synaptic targeting, anchoring and turnover of AMPA receptors consists of several types of specialized scaffolding proteins. The FERM domain scaffolding proteins 4.1G and 4.1N were previously suggested to act jointly in binding and regulating synaptic trafficking of the AMPA receptor subunits GluR1 and GluR4. To determine the functions of 4.1G and 4.1N in vivo, we generated a mutant mouse line that lacks 4.1G entirely and expresses 4.1N at 22% of wild-type levels. These mice had combined 4.1G and 4.1N protein expression in the hippocampus at 12% of wild-type levels (equivalent to 8-10% of combined GluR1 and GluR4 expression levels). They show a moderate reduction in synaptosomal expression levels of the AMPA receptor subunit GluR1 at 3 weeks of age, but no change in basic glutamatergic synaptic transmission and long-term potentiation in the hippocampus. Our study indicates that 4.1G and 4.1N do not have a crucial role in glutamatergic synaptic transmission and the induction and maintenance of long-term plastic changes in synaptic efficacy.
Stability of a Conductive State of Poly(3-alkoxythiophene)s
Authors: Hatakeyama Kouji , Koizumi Hitoshi , Ichikawa Tsuneki
Published: February 2009

Stability of a conductive state of iodine-doped poly(3-octyloxythiophene) (P3OOT) was compared with that of poly(3-octylthiophene) (P3OT). Temporal decay in the electric conductivity of P3OOT after the doping was much slower than that of P3OT. The cation of P3OOT was stable and an increase in the spin concentration was not observed. The results support the mechanism of dedoping of poly(3-alkylthiophene)s proposed by the authors [J. Phys. Chem. B2005, 109, 15288]: the dedoping proceeds through deprotonation of the cation, which results in the formation of a stable polyenyl radical. The deprotonation of the cation of P3OOT occurs with difficulty since deprotonation gives an unstable radical. The conductive state of P3OOT is hence stable.
Tunneling Effect in Antioxidant Reaction of Flavonoid
Authors: Kakiuchi Takuhiro , Mukai Kazuo , Ohara Keishi , Nagaoka Shin-ichi
Published: February 2009

A study of the kinetics of the proton-transfer reaction in flavonoid in ethanol solution by means of stopped-flow spectroscopy indicated that proton tunneling plays an important role in the antioxidant reaction.
Fluorescence Characteristics of Naphthalene Dendrimers at Low Concentration in Aqueous Solution
Authors: Akatsuka Ryosuke , Shinohara Yoshihiro , Sato Tomoo , Nishimura Yoshinobu , Arai Tatsuo
Published: February 2009

Water-soluble naphthalene dendrimers WN1, WN2, and WN3, together with the lipophilic compounds N1, N2, and N3 were prepared and their photochemical properties were examined. Whereas lipophilic dendrimers N1, N2, and N3 gave monomer emission peaking at 330–340 nm, water-soluble dendrimers WN1, WN2, and WN3 gave not only the monomer emission at 330–340 nm but also excimer emission peaking at 400 nm in aqueous solution under considerably diluted conditions. The relative intensity of the excimer fluorescence at longer wavelengths compared to the monomer emission depended on the dendrimer generation and the concentration of dendrimer and added salt (KCl). In particular the excimer emission of the second generation dendrimer is considerably higher than those of the first and the third generation dendrimers. Based on these experimental results, the aggregation and the excimer formation of water-soluble naphthalene dendrimers in aqueous solution depending on the generation and the conditions were discussed.
Synthesis of Water-Soluble Dendritic Phosphine Ligands and Their Application to Hydration of Alkynes in Aqueous Media
Authors: Fujita Ken-ichi , Kujime Masato , Muraki Takahito
Published: February 2009

A series of water-soluble dendritic ligands with a phosphine core was synthesized through the coupling of tris(4-hydroxyphenyl)phosphine oxide with poly(benzyl ether) dendron having tri(ethylene glycol) units, followed by reduction. By employing the corresponding water-soluble phosphine–gold(I) dendrimers as a catalyst, the hydration of alkynes proceeded smoothly. Furthermore, by membrane separation based on the nano-order size of the dendritic catalyst, the gold(I) catalyst was recycled without deactivation.
Synthesis of a Linked [1]–[1]Rotaxane
Authors: Tsuda Susumu , Terao Jun , Tsurui Keisuke , Kambe Nobuaki
Published: February 2009

Highly organic soluble [1]–[1]rotaxane also known as linked [3]rotaxane was synthesized by intramolecular self-inclusion of a modified permethylated α-cyclodextrin (PM α-CD) to form a pseudo[1]rotaxane followed by dimerization. The NMR spectroscopy of thus formed rotaxane suggests that the diphenylacetylene units are fully encapsulated by the PM α-CDs. The Stern–Volmer analysis of fluorescence quenching using a viologen analogue shows that the PM α-CDs inhibits electron transfer efficiently suggesting a high coverage ratio of the π-conjugated axle with the PM α-CDs.
Synthesis and Structure-specific Functions of Patchy Nanoparticles
Authors: Teranishi Toshiharu , Saruyama Masaki , Kanehara Masayuki
Published: February 2009

Anisotropically phase-segregated nanoparticles, so-called patchy nanoparticles, are promising materials, because the close coupling of different components on the nanoscale may significantly improve application performance or even create new properties. We demonstrate that the seed-mediated growth method is quite effective in synthesizing various kinds of patchy nanoparticles consisting of a combination of metals, metal sulfides, and metal oxides.
Circularly Polarized Luminescence from Supramolecular Chiral Complexes of Achiral Conjugated Polymers and a Neutral Polysaccharide
Authors: Haraguchi Shuichi , Numata Munenori , Li Chun , Nakano Yoko , Fujiki Michiya , Shinkai Seiji
Published: February 2009

We have developed a novel approach to the preparation of a circularly polarized luminescence material from a natural polysaccharide host and an achrial polythiophene guest.
Fabrication of Hollow TiO2 Fibers Templated by Electrospun Aqueous Poly(ethylene oxide) (PEO) Solution
Authors: Nagamine Shinsuke , Tanaka Yoshitaka , Ohshima Masahiro
Published: February 2009

Hollow TiO2 fibers were fabricated by electrospinning an aqueous solution of poly(ethylene oxide) (PEO) and introducing the thread-like droplets directly into a titanium tetraisopropoxide (TTIP)/hexane solution, inducing the rapid hydrolysis and condensation of TTIP at the interface between the PEO solution and TTIP solution. Various hollow structures including submicron hollow fibers, thick fibers with a diameter of tens of micrometers, and spherical micron particles could be systematically synthesized by varying the molecular weight and concentration of PEO solution.
Preparation and Electrochemical Properties of Pt@C Nanocomposites
Authors: Sun Li , Zhao Yongnan , Yu Jianguo , Wang Huiqi
Published: February 2009

By using maize as the carbon source, well-dispersed Pt nanoparticles embedded in carbon matrix (Pt@C) are prepared by soaking corn in K2PtCl6 solutions followed by calcination in nitrogen atmosphere. Linear sweep voltammograms exerted on the Pt@C nanocomposites reveal a good current response to methanol oxidation.
An Immobilized Lipase Microfluidic Reactor for Enantioselective Hydrolysis of Ester
Authors: Gao Yan , Zhong Runtao , Qin Jianhua , Lin Bingcheng
Published: February 2009

Enantioselective enzymatic hydrolysis of racemic mixture is an effective method to obtain pure enantiomer. In this report, an immobilized lipase microfluidic reactor was fabricated and applied to enantioselective hydrolysis of racemic 1-phenylethyl acetate to obtain (R)-1-phenylethanol. This immobilized lipase microfluidic reactor consumed trace amount of enzyme, showed identical performance compared to free enzyme in batch, and good stability that can be recycled for at least eight times without obvious loss of activity.
Stability of Chemically Modified Indium–Tin–Oxide Surfaces against Water
Authors: Hattori Masashi , Suga Kosaku , Fujihira Masamichi
Published: February 2009

We studied stability of indium–tin–oxide (ITO) surfaces chemically modified with –SO2Cl and –PO2Cl2 binding groups of para substituted benzene derivatives as well as those oxidized with UV ozone by measuring time dependence of the work function and water contact angle after their surface modifications. It seems most likely from the effect of water contents in environments upon their time changes that water is the primary reactant for degradation of the chemically modified and oxidized ITO surfaces.
The upper limit of the reference range for thyroid-stimulating hormone should not be confused with a cut-off to define subclinical hypothyroidism
Authors: Waise Ahmed , Price Hermione C
Published: February 2009

The upper limit of the reference range for serum thyroid-stimulating hormone (TSH) is used to assist in identifying individuals with hypothyroidism. Improvements in TSH assays have led to better definition of the lower limit of the reference range, but the upper limit of the range for a healthy population is currently a topic of some debate. Population studies have improved our understanding of the clinical implications of elevated serum TSH concentrations in terms of future progression to hypothyroidism, but have not yet fully elucidated the correlation of modestly elevated TSH levels with long-term morbidity. This paper will review the current debate including the arguments for and against reducing the upper limit of the TSH range, whether such a level should be based on evidence from epidemiological studies, and the implications of categorizing large numbers of people with subclinical hypothyroidism. The impact of using different methodologies for the measurement of TSH and the inherent variability of results on reference ranges is also discussed. We argue that the reference range for TSH should be assay-specific and be determined by standard techniques in normal populations as recommended by the National Academy of Clinical Biochemistry. In contrast, we suggest that a decision level be determined separately from epidemiological studies to identify a population with subclinical hypothyroidism. Serial monitoring of TSH in this population deserves further study as a means of identifying those at risk of progressing to frank hypothyroidism and meriting treatment.
Interference of paracetamol (acetaminophen) with a commercially available high-performance liquid chromatography analysis of serotonin leading to falsely low serotonin levels
Authors: Pfäfflin Albrecht , Müssig Karsten , Schleicher Erwin
Published: February 2009

Serotonin is frequently analysed by high-performance liquid chromatography (HPLC) with electrochemical detection. However, the accuracy of these methods may be affected by the presence of certain drugs. We describe for the first time the interference of paracetamol in therapeutic dosages in a routine HPLC method for serotonin determination in vivo and in vitro. The retention time coincides with N-methylserotonin used as an internal standard in this method. Erroneous increases of the internal standard will lead, if not recognized and corrected, to falsely low serotonin determinations.
The rise and fall of C-reactive protein: managing demand within clinical biochemistry
Authors: Hutton H D , Drummond H S , Fryer A A
Published: February 2009

Background

Managing workload within the laboratory has become a key role for clinical biochemists. National benchmarking data highlighted a 31% increase in C-reactive protein (CRP) requests between 2003–2004 and 2004–2005 for the University Hospital of North Staffordshire (UHNS). The aim of this study was to examine CRP requesting patterns within the acute admissions units.

Methods

Current requesting patterns within the Accident and Emergency Department (A&E) and Medical Admissions Unit (MAU) were audited. Following discussion with clinical colleagues, the laboratory implemented agreed disease-related protocols and consultant only requesting. The impact these demand management strategies had on requesting within these units was then assessed.

Results

The initial data (January–June 2005) showed that the average number of requests for CRP was 918 per month from A&E and 545 per month for MAU. Implementation of demand-management strategies resulted in an overall reduction of 85% in the numbers of requests, saving the Trust approximately £10,000 per annum. Further to the initial protocols, an IT-based logic rule was also developed to reduce CRP requests made within a 24 h time window of an initial request and educate users.

Conclusion

This study has demonstrated that strategies to control demand at the requesting stage have been able to reduce the number of requests from acute admission units. This study forms the basis for ongoing work on inappropriate requesting and illustrates that the introduction of agreed protocols in acute settings can be used as a demand-management tool.
Iron polymaltose-induced FGF23 elevation complicated by hypophosphataemic osteomalacia
Authors: Schouten Belinda J , Doogue Matthew P , Soule Steven G , Hunt Penelope J
Published: February 2009

Iron-induced renal phosphate wasting, hypophosphataemia and osteomalacia have previously been reported in a small number of Japanese patients receiving parenteral iron sucrose. We report the case history of a European male who, as a result of regular intravenous iron polymaltose, developed prolonged hypophosphataemia complicated by widespread insufficiency fractures. The pathogenesis of this complication remains unknown however our novel finding of a marked elevation in fibroblast growth factor 23 (FGF23), which normalized after ceasing parenteral iron, suggests an important and previously unreported effect of iron on FGF23 homeostasis.
Appropriateness of the National Academy of Clinical Biochemistry recommendation of repeating HbA1c analysis for extreme results in clinical practice
Authors: Yalamati P , Jones B J , Twomey P J
Published: February 2009

Background

The National Academy of Clinical Biochemistry (NACB) recommends that the presence of a variant or modified haemoglobin be considered when any HbA1c result is below the lower limit of the reference interval or ≥15%. In those instances where a variant haemoglobin is suspected, repeat measurement using an alternative method is the usual course of action. In the present study, we undertook to determine the impact of this guideline on our identification of variant and modified haemoglobins.

Methods

All requests for HbA1c estimation received over a 32-month period, and which gave a result of <4% or >15% were re-analysed by a different method and the results compared.

Results

Over the 32-month period, 94 samples with a HbA1c result of <4% or ≥15% were identified. Of these, 80 were re-analysed using a different method. No chromatographic abnormalities were seen and there were no significant differences between the results obtained using the two methods.

Conclusions

No variant or modified haemoglobins were identified in this study and this observation is likely to be representative of the ethnic makeup of our patient population. On the basis of this finding, we recommend that laboratories consider local factors when deciding whether to comply with the NACB guidelines.
Evaluation of the particle gel diffusion technique for the detection of haemoglobin S in Sudanese patients
Authors: Nimir Ahmed A , Khalil Eltahir A G , Musa Ahmed M , Yassin Habab M , El-Hassan Ahmed M
Published: February 2009

Background

Sickle cell disease is a heterogenous disorder characterized by an abnormal haemoglobin and sickling phenomena of red cells. It is prevalent among certain nomadic tribes in Sudan. Painful, aplastic and haemolytic crises mark sickle cell anaemia. Haemoglobin S (HbS) is detected using haemoglobin electrophoresis, iso-electric focusing and/or high-performance liquid chromatography techniques with high sensitivity, but entails cost and expertise. This study aimed to determine the sensitivity, specificity and positive predictive values (PPV) of the ID-particle gel diffusion technique for screening, diagnosis and phenotyping of HbS in patients with a provisional diagnosis of abnormal haemoglobin.

Methods

Following informed consent, 100 sequential individuals who reported to a central referral haemoglobinopathy clinic were enrolled. ID-particle gel diffusion technique was compared with cellulose acetate electrophoresis to determine haemoglobin phenotypes.

Results

The ID-particle gel test detected HbAA with 100% sensitivity and 100% specificity. Sensitivity for HbS was 100%, whether as HbSS or as a mixed pattern. HbSS was identified in all cases where this is the only haemoglobin present. Other patterns were detected with <100% specificity and these would require further testing by other means to definitively identify abnormal haemoglobins.

Conclusions

Although the ID-particle technique is a simple and cheap technique with high sensitivity, specificity and PPV compared with cellulose acetate electrophoresis in detecting HbSS, it could not differentiate HbAS from HbSS with high levels of HbF. High environmental temperatures could melt the test microtubes. Cellulose acetate electrophoresis remains the technique of choice for the screening of abnormal haemoglobins in the Sudan.
Predictive accuracy and sources of variability in calculated free testosterone estimates
Authors: Sartorius Gideon , Ly Lam P , Sikaris Ken , McLachlan Robert , Handelsman David J
Published: February 2009

Background

Serum free testosterone (FT) concentrations are commonly requested, but because reference FT methods are too laborious various calculational algorithms for FT based on total testosterone (TT) and sex hormone-binding globulin (SHBG) are frequently used. This study provides the first large-scale evaluation of the predictive accuracy and sources of variability for different FT formulae compared with direct laboratory measurements.

Methods

Using a large data-set of direct FT measurements by centrifugal ultrafiltration, the predictive accuracy of five different formulas for cFT (four existing plus a new formula) is evaluated in 3975 consecutive blood samples. In a second data-set of 124 samples from a reference panel of healthy eugonadal young men, we estimate the relative influence of the five algorithms and eight different TT and two SHBG assays including all available commercial total TT and SHBG assays together with a gas chromatography/mass spectrometry T reference method.

Results

cFT formulae show wide discrepancies with equilibrium-binding algorithms showing systematic overestimation relative to direct FT measurements, whereas two empirical cFT methods were more concordant. Variations between commercially available TT immunoassays have a strong impact on calculation of FT with TT assays contributing 82.2% of overall variance compared with 13.7% for the cFT algorithms and 4.1% for the SHBG assays.

Conclusions

If FT measurements are requested and direct measurement impractical, cFT formulae using TT and SHBG immunoassays provide an approximation to direct FT measurement that is strongly dependent on the TT, cFT formula used and, to a lesser extent, SHBG immunoassays.
Primary antibody deficiency syndromes
Authors: Wood P
Published: February 2009

The primary antibody deficiency syndromes are a group of rare disorders characterized by an inability to produce clinically effective immunoglobulin responses. Some of these disorders result from genetic mutations in genes involved in B cell development, whereas others appear to be complex polygenic disorders. They most commonly present with recurrent infections due to encapsulated bacteria, although in the most common antibody deficiency, Common Variable Immunodeficiency, systemic and organ-specific autoimmunity can be a presenting feature. Diagnostic delay in this group of disorders remains a problem, and the laboratory has a vital role in the detection of abnormalities in immunoglobulin concentration and function. It is critical to distinguish this group of disorders from secondary causes of hypogammaglobulinaemia, in particular lymphoid malignancy, and appropriate laboratory investigations are of critical importance. Treatment of primary antibody deficiencies involves immunoglobulin replacement therapy, either via the intravenous or subcutaneous route. Patients remain at risk of a wide variety of complications, not all linked to diagnostic delay and inadequate therapy. In common variable immunodeficiency (CVID) in particular, patients remain at significantly increased risk of lymphoid malignancy, and regular clinical and laboratory monitoring is required. This review aims to give an overview of these conditions for the general reader, covering pathogenesis, clinical presentation, laboratory investigation, therapy and clinical management.
An audit on the reporting of critical results in a tertiary institute
Authors: Rensburg Megan A , Nutt Louise , Zemlin Annalise E , Erasmus Rajiv T
Published: February 2009

Background

Critical result reporting is a requirement for accreditation by accreditation bodies worldwide. Accurate, prompt communication of results to the clinician by the laboratory is of extreme importance. Repeating of the critical result by the recipient has been used as a means to improve the accuracy of notification. Our objective was to assess the accuracy of notification of critical chemical pathology laboratory results telephoned out to clinicians/clinical areas. We hypothesize that read-back of telephoned critical laboratory results by the recipient may improve the accuracy of the notification.

Methods

This was a prospective study, where all critical results telephoned by chemical pathologists and registrars at Tygerberg Hospital were monitored for one month. The recipient was required to repeat the result (patient name, folder number and test results). Any error, as well as the designation of the recipient was logged.

Results

Of 472 outgoing telephone calls, 51 errors were detected (error rate 10.8%). Most errors were made when recording the folder number (64.7%), with incorrect patient name being the lowest (5.9%). Calls to the clinicians had the highest error rate (20%), most of them being the omission of recording folder numbers.

Conclusion

Our audit highlights the potential errors during the post-analytical phase of laboratory testing. The importance of critical result reporting is still poorly recognized in South Africa. Implementation of a uniform accredited practice for communication of critical results can reduce error and improve patient safety.
Salivary paracetamol: evaluation of a colorimetric method in assessing deliberate self-poisoning
Authors: Ryan Joshua , Mandelt Christine , Wade Heidi , Vasikaran Samuel D
Published: February 2009

Background

In the laboratory evaluation of suspected paracetamol poisoning, a non-invasive sample type that avoids venepuncture would be an attractive alternative to plasma, particularly in the paediatric setting. Salivary paracetamol measurement has not previously been evaluated in the published medical literature in the setting of deliberate self-poisoning (DSP).

Methods

In-house validation experiments (recovery, stability and lower limit-of-detection) were performed on pooled saliva samples using a Roche Acetaminophen assay on a Roche/Hitachi 917 analyser. A clinical study of comparison of paired saliva and plasma samples was also conducted involving adult patients presenting with DSP of paracetamol, the results of which were published previously.

Results

The validation experiments using pooled saliva samples showed: (i) mean recovery (paracetamol concentration 37.5–525 mg/L) 100.01% (±0.02 SD); (ii) precision of repeated assay over 24-h period CV <4%; (iii) lower limit-of-detection 0.9 mg/L. The clinical study of 21 patients with mean plasma paracetamol concentration of 48 mg/L (range 0–130) and mean saliva concentration 62 mg/L (range 0–183) showed good correlation between saliva and plasma concentrations ( r2 = 0.91).

Conclusions

The Roche Hitachi 917 Acetaminophen assay is suitable for the measurement of paracetamol in saliva. Further studies comparing plasma and saliva samples from patients with DSP and plasma paracetamol concentrations in the hepatotoxic range are warranted. If salivary samples are suitable for risk-stratifying patients with paracetamol DSP, venepuncture may be avoided, which would be attractive, especially in the paediatric setting.
The cytoskeleton-associated Ena/VASP proteins are unanticipated partners of the PMR1 mRNA endonuclease
Authors: Peng Yong , Murray Elizabeth L. , Sarkar Madhubanti , Liu Xiaoqiang , Schoenberg Daniel R.
Published: February 2009

The PMR1 mRNA endonuclease catalyzes the selective decay of a limited number of mRNAs. It participates in multiple complexes, including one containing c-Src, its activating kinase, and one containing its substrate mRNA. This study used tandem affinity purification (TAP) chromatography to identify proteins in HeLa cell S100 associated with the mature 60-kDa form of Xenopus PMR1 (xPMR60). Unexpectedly, this identified a number of cytoskeleton-associated proteins, most notably the Ena family proteins mammalian Enabled (Mena) and vasodilator-stimulated phosphoprotein (VASP). These are regulators of actin dynamics that distribute throughout the cytoplasm and concentrate along the leading edge of the cell. xPMR60 interacts with Mena and VASP in vivo, overexpression of Mena has no impact on mRNA decay, and Mena and VASP are recovered together with xPMR60 in each of the major complexes of PMR1-mRNA decay. In a wound-healing experiment induced expression of active xPMR60 in stably transfected cells resulted in a twofold increase in cell motility compared with uninduced cells or cells expressing inactive xPMR60°. Under these conditions xPMR60 colocalizes with VASP along one edge of the cell.
mRNA stability changes precede changes in steady-state mRNA amounts during hyperosmotic stress
Authors: Molin Claes , Jauhiainen Alexandra , Warringer Jonas , Nerman Olle , Sunnerhagen Per
Published: February 2009

Under stress, cells need to optimize the activity of a wide range of gene products during the response phases: shock, adaptation, and recovery. This requires coordination of several levels of regulation, including turnover and translation efficiencies of mRNAs. Mitogen-activated protein (MAP) kinase pathways are implicated in many aspects of the environmental stress response, including initiation of transcription, translation efficiency, and mRNA turnover. In this study, we analyze mRNA turnover rates and mRNA steady-state levels at different time points following mild hyperosmotic shock in Saccharomyces cerevisiae cells. The regulation of mRNA stability is transient and affects most genes for which there is a change in transcript level. These changes precede and prepare for the changes in steady-state levels, both regarding the initial increase and the later decline of stress-induced mRNAs. The inverse is true for stress-repressed genes, which become stabilized during hyperosmotic stress in preparation of an increase as the cells recover. The MAP kinase Hog1 affects both steady-state levels and stability of stress-responsive transcripts, whereas the Hog1-activated kinase Rck2 influences steady-state levels without a major effect on stability. Regulation of mRNA stability is a wide-spread, but not universal, effect on stress-responsive transcripts during transient hyperosmotic stress. By destabilizing stress-induced mRNAs when their steady-state levels have reached a maximum, the cell prepares for the subsequent recovery phase when these transcripts are to return to normal levels. Conversely, stabilization of stress-repressed mRNAs permits their rapid accumulation in the recovery phase. Our results show that mRNA turnover is coordinated with transcriptional induction.
Molecular dynamics suggest multifunctionality of an adenine imino group in acid-base catalysis of the hairpin ribozyme
Authors: Ditzler Mark A. , Šponer Jiří , Walter Nils G.
Published: February 2009

Despite numerous structural and biochemical investigations, the catalytic mechanism of hairpin ribozyme self-cleavage remains elusive. To gain insight into the coupling of active site dynamics with activity of this small catalytic RNA, we analyzed a total of ∼300 ns of molecular dynamics (MD) simulations. Our simulations predict improved global stability for an in vitro selected “gain of function” mutation, which is validated by native gel electrophoretic mobility shift assay. We observe that active site nucleobases and water molecules stabilize a geometry favorable to catalysis through a dynamic hydrogen bonding network. Simulations in which A38 is unprotonated show its N1 move into close proximity of the active site 2′-OH, indicating that A38 may act as a general base during cleavage, a role that has generally been discounted due to the longer distances observed in crystal structures involving inactivating substrate analogs. By contrast, simulations in which N1 of A38 is protonated place N1 in close proximity to the 5′-oxygen leaving group, which supports the proposal that A38 serves as a general acid. In analogy to protein enzymes, we discuss a plausible mechanism in which A38 acts bifunctionally and shuttles a proton directly from the 2′-OH to the 5′-oxygen. Furthermore, our simulations suggest an important role for protonation of N1 of A38 in promoting a favorable geometry similar to that observed in transition-state analog crystal structures, and support previously proposed roles of A38, G8, and long residency water molecules in transition-state stabilization.
RNA localization to the Balbiani body in Xenopus oocytes is regulated by the energy state of the cell and is facilitated by kinesin II
Authors: Heinrich Bianca , Deshler James O.
Published: February 2009

Xenopus oocytes provide an excellent model system for understanding the cis-elements and protein factors that carry out mRNA localization in vertebrate cells. More than 20 mRNAs have been identified that localize to the vegetal cortex during stages II–IV of oogenesis. The earliest localizing RNAs are presorted to a subcellular structure, the Balbiani body (also called the mitochondrial cloud in Xenopus), of stage I oocytes prior to entering the vegetal cortex. While some evidence has suggested that diffusion drives RNA localization to the Balbiani body, a role for temperature and metabolic energy in this process has not been explored. To address this issue, we developed a quantitative assay to monitor RNA localization in stage I oocytes. Here we show that the rate of RNA accumulation to the Balbiani body is highly dependent on temperature and the intracellular concentration of ATP. In fact, while ATP depletion severely impairs RNA localization, increasing the intracellular concentration of ATP by a factor of two doubles the localization rate, indicating that ATP is limiting under normal conditions. We also show that RNA localization in stage I oocytes is reduced by inhibition of kinesin II, and that the Xcat-2 RNA localization element recruits kinesin II to the Balbiani body. We conclude from these studies that the energy state of the cell regulates the rate of RNA localization to the Balbiani body and that this process, at least to some extent, involves kinesin II.
Expression of Integrin αvβ6 and TGF-β in Scarless vs Scar-forming Wound Healing
Authors: Eslami Ameneh , Gallant-Behm Corrie L. , Hart David A. , Wiebe Colin , Honardoust Dariush , Gardner Humphrey , Häkkinen Lari , Larjava Hannu S.
Published: February 2009

Oral mucosal wounds heal with reduced scar formation compared with skin. The epithelial integrin αvβ6 is induced during wound healing, and it can activate fibrogenic transforming growth factor β1 (TGF-β1) and anti-fibrogenic TGF-β3 that play key roles in scar formation. In this study, expression of β6 integrin and members of the TGF-β pathway were studied in experimental wounds of human gingiva and both gingiva and skin of red Duroc pigs using real-time PCR, gene microarrays, and immunostaining. Similar to human wounds, the expression of β6 integrin was induced in the pig wounds 7 days after wounding and remained upregulated >49 days. The αvβ6 integrin was colocalized with both TGF-β isoforms in the wound epithelium. Significantly higher expression levels of β6 integrin and TGF-β1 were observed in the pig gingival wounds compared with skin. Early gingival wounds also expressed higher levels of TGF-β3 compared with skin. The spatio-temporal colocalization of αvβ6 integrin with TGF-β1 and TGF-β3 in the wound epithelium suggests that αvβ6 integrin may activate both isoforms during wound healing. Prolonged expression of αvβ6 integrin along with TGF-β3 in the gingival wound epithelium may be important in protection of gingiva from scar formation.
An Appraisal of Intermediate Filament Expression in Adult and Developing Pancreas: Vimentin Is Expressed in α Cells of Rat and Mouse Embryos
Authors: Bella Alessandro Di , Regoli Marì , Nicoletti Claudio , Ermini Leonardo , Fonzi Luciano , Bertelli Eugenio
Published: February 2009

Intermediate filaments are frequently used in studies of developmental biology as markers of cell differentiation. To assess whether they can be useful to identify differentiating pancreatic endocrine cells, we examined the pattern of expression of nestin, cyto-keratin 20, and vimentin on acetone-fixed cryosections of rat adult and developing pancreas. We also studied vimentin expression in mouse embryonic pancreas at E19. Cytokeratin 20 was found in all pancreatic epithelial cell lineages during the entire development of the rat gland and in the adult animals. Under our experimental conditions, therefore, cytokeratin 20 is not an exclusive marker of rat duct cells. Nestin was detected exclusively in stromal cells either in the adult or developing rat pancreas. Vimentin was observed within cells located in the primitive ducts of rat pancreas starting from E12.5. Their number rapidly increased, reaching its highest level in newborn animals. Vimentin was also spotted in α cells starting from E12.5 but disappeared soon after birth, likely identifying immature or recently differentiated α cells. In addition, vimentin was observed in duct and α cells of mouse developing pancreas showing that its expression in such cells is not an event restricted to the rat. This manuscript contains online supplemental material at http://www.jhc.org . Please visit this article online to view these materials.
Use of Human Vascular Tissue Microarrays for Measurement of Advanced Glycation Endproducts
Authors: Halushka Marc K. , Selvin Elizabeth , Lu Jie , Macgregor Anne M. , Cornish Toby C.
Published: February 2009

Advanced glycation endproducts (AGEs) are present in the vasculature and are associated with vascular disease. We determined levels of AGEs in eight distinct adult vascular tissues using tissue microarray (TMA) technology and associated these levels with clinical characteristics. Medium-to-large caliber blood vessels were harvested from 100 adult autopsies to create 17 TMAs. AGE levels were evaluated by IHC using a polyclonal anti-AGE antibody on over 700 unique blood vessels. Slides were digitally scanned, and quantitative analysis was performed using a color deconvolution image analysis technique. Medial AGE staining was strongly correlated between all eight blood vessels. In the media, AGE staining levels were significantly higher at older ages ( p=0.009), in white subjects ( p<0.001) and with longer postmortem interval (PMI; p<0.0001). These associations remained significant after simultaneous adjustment for age, race/ethnicity, PMI, and diabetes status. Diabetes was associated with elevated AGE levels but only after adjustment for confounding by clinical variables including race/ethnicity, hypertension, and kidney function. This extensive vascular study shows that AGE accumulation in the macrovasculature is a global process affecting atherosclerosis-prone and -resistant vessels. It also suggests ethnicity has a previously unde-scribed role in vascular tissue AGE levels. This manuscript contains online supplemental material at http://www.jhc.org . Please visit this article online to view these materials.
Römisches Reich im Frühmittelalter. Kaiserlich-päpstliches Kondominat, salischer HerrschaftsverbandRoman Empire in the Early Middle Ages. Imperial-Papal Co-Domination, Salian Domain
Authors: Müller-Mertens Eckhard
Published: February 2009

Die Untersuchung ist an ihr Ziel gelangt, das Jahr 1073 mit Antworten auf die Fragen: Wann gaben die Zeitgenossen dem mittelalterlichen, die Alpen übergreifenden, dem Alten Reich den Namen Römisches Reich? Welches politische Gebilde überhaupt wurde nach der Kaiserkrönung 800 als Romanum imperium begriffen? Ersteres geschah in der frühen Salierzeit, in der politischen Theorie und Historiographie zuerst durch Wipos Gesta Chuonradi, vorweg indes Urkunden dieses Kaisers, deren erste mit der neuen Kaiserbulle Rom, das Haupt der Welt, regiert den Erdkreis beglaubigt wurde. Die Geschichtsschreibung folgte einhellig, schließlich nannte Gregor VII. den Herrschaftsverband Heinrichs IV. als Ganzes Römisches Reich. In der Karolinger- und Ottonenzeit bezeichnete Romanum imperium die Kaiserherrschaft über Rom und das römische Italien. Das waren die Gebiete Mittelitaliens, die bis dahin zum römisch-byzantinischen Reich gehörten, der Dukat von Rom und das Exarchat Ravenna mit der Pentapolis, die 800 einen eigenen, in Rom vom Papst geweihten und den Römern ausgerufenen Kaiser erhielten, das fortan kaiserlich-päpstliche Kondominat in Mittelitalien, gegründet auf die Verträge der Kaiser und Päpste von Pippin 754 bis Heinrich II. 1020. Eine politisch-theoretische Definition quasi gab in der Mitte des 9. Jahrhunderts Anastasius Bibliothecarius. Von ottonischen Geschichtsschreibern wurde dieses Römische Reich als krönender Zugewinn des liudolfingischen Hauses angesehen, es wurde neben das nordalpine Reich und das Reich Italien gestellt. Der Vorstellung des bestehenden Römischen Reiches im Frühmittelalter war kein universaler Anspruch immanent. Es spielte in der Liturgie einschließlich der Krönungsordines kaum eine, in der Eschatologie keine maßgebliche Rolle, kam in der Panegyrik mit einer antiken Reminiszenz zur Geltung. Einen Vorrang bezog die römische Kaiserherrschaft aus der Kaiserweihe durch den Papst, die Aufgabe des Kaisers, die Römische Kirche zu verteidigen und zu erhöhen, die Beziehung auf Rom. Im Romanum imperium des Frühmittelalters konkretisierte sich das Bündnis des Papsttums und der weltlichen Vormacht im Okzident. In dieser Funktion stellte sich das auf die Pakten, auf Rom und das römische Italien bezogene Römische Reich als eine konstitutive Größe der Formierung Lateineuropas, des mittelalterlichen Abendlandes dar. Die Erweiterung der Vorstellung auf den die Alpen übergreifenden Herrschaftsverband insgesamt, sicher aus mehreren Gründen, die Übertragung des Namens Romanum imperium vom kaiserlich-päpstlichen Kondominat in Mittelitalien auf den salischen Herrschaftsverband als Ganzes vollzog sich vor dem Hintergrund der transalpinen Konfigurations- und Integrationsprozesse seit 962, der Extensivierung und Intensivierung der Kaiser- und Königsherrschaft unter Heinrich II. und den ersten Saliern.