bluuebunny/crossref_metadata_2025 huggingface dataset:
The crystallization of ultrathin films of polylactides — Morphologies and transitions
Authors: Maillard Damien , Prud’homme Robert E
Published: May 2008

Poly(L-lactide) ultrathin films of thicknesses between 10 and 80 nm were crystallized between 100 and 170 °C. Four different morphologies were obtained: single crystals, hedrites, dendrites, and spherulites. Dendrites were always obtained below 20 nm due to chain diffusion limitations, whereas, at larger thicknesses, the morphology heavily depends on the crystallization temperature. The thickness-temperature morphological map led to the observation of two transition temperatures, at 115 and 145 °C. Other parameters such as the lamellar thickness, melting temperature, and dendricity of the lamellae for 15 nm thick films show significant changes at these two temperatures. Those transitions occur at the same temperatures as Regime III/Regime II, and Regime II/Regime I transitions of the Lauritzen–Hoffman crystallization theory.Key words: polylactide, ultrathin film, crystalline morphology, single crystal, dendrite, spherulite, transition temperature, regime of crystallization.
Biological production of functional chemicals from renewable resources
Authors: Tokiwa Yutaka , Calabia Buenaventurada P
Published: May 2008

The development and implementation of renewable feedstocks for the production of multifunctional chemicals has received attention from the food and pharmaceutical industries and also as potential raw materials for the manufacture of biodegradable polymers. A major shift towards renewable resources, however, requires new ways to optimize and evaluate industrial processes. There are several possibilities to replace chemical techniques with biological methods based on renewable resources. This review discusses some examples of process development in which a biotechnological route might be favorable leading to industrial realization. Herein are described the production of biomaterials that can be used as monomers in plastics, such as lactic acid for polylactide (PLA), (R)-3-hydroxybutyric acid (R-3HB) for poly[(R)-3-hydroxybutyrate] (PHB), and succinic acid for poly(butylene succinate) (PBS). Moreover, several species of microorganisms that produce significant quantities of these functional chemicals under specific cultivation conditions from biomass-derived carbohydrates are also reviewed.Key words: functional chemicals, renewable resources, lactic acid, (R)-3-hydroxybutyric acid, succinic acid.
Targeted engineering of Cupriavidus necator chromosome for biosynthesis of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) from vegetable oil
Authors: Mifune Jun , Nakamura Satoshi , Fukui Toshiaki
Published: May 2008

Previous studies have demonstrated that heterologous expression of PHA synthase from Aeromonas caviae (PhaCAc), capable of accepting (R)-3-hydroxyacyl-CoA of C4–C7 as substrates, could confer the ability to PHA-negative mutant of Cupriavidus necator PHB-4 to synthesize poly((R)-3-hydroxybutyrate-co-(R)-3-hydroxyhexanoate) [P(3HB-co-3HHx)] from vegetable oils. The mutation point within pha operon in PHB-4 was determined to be a single nonsense mutation within the PHA synthase gene (phaCCn), suggesting the much lower β-ketothiolase and NADPH-dependent acetoacetyl-CoA reductase activities observed in this strain would be a polar effect of the mutation. For further efficient biosynthesis of P(3HB-co-3HHx) copolyester, C. necator wild strain H16 was engineered by homologous recombination targeting the chromosomal phaCCn, and the PHA productivity was compared with previous PHB–4-derived strain harboring phaCAc on a multi-copy plasmid (PHB–4/pJRDEE32d13). A strain H16CAc, in which phaCCn was substituted for phaCAc on the chromosome, could produce P(3HB-co-3HHx) from soybean oil with high productivity, but the 3HHx fraction in the accumulated polymer was decreased. Meanwhile, H16ΔC/pJRDEE32d13, that lost region for the original synthase gene and expresses exochromosomal phaCAc, grew and accumulated PHA with similar properties to the PHB–4-derived strain. The results of enzyme assay suggested that low β-ketothiolase activity might be relevant for decrease of growth ability accompanied by increase of 3HHx composition when soybean oil was fed as a sole carbon source. Key words: poly(hydroxyalkanoates), poly(3-hydroxybutyrate-co-3-hydroxyhexanoate), PHA synthase, Cupriavidus necator, vegetable oil.
Poly(hydroxyalkanoates): Biorefinery polymers with a whole range of applications. The work of Robert H. Marchessault
Authors: Orts William J , Nobes Geoffrey A.R. , Kawada Jumpei , Nguyen Sophie , Yu Ga-er , Ravenelle François
Published: May 2008

This review describes the characterization and application of poly(hydroxyalkanoates), PHAs, a remarkable family of natural polyesters with a wide array of useful properties and potential applications. It places specific emphasis on the work of Robert H. Marchessault and his many colleagues outlining how Marchessault’s body of work both shaped the field and complemented the work of his contemporaries. Particular attention will focus on the “rediscovery” of poly(β-hydroxybutyrate), PHB, the first PHA to be discovered, from the late 1950s onward, highlighting some of the historical aspects of PHA’s path toward commercial applications. It will also cover why this class of materials is so unique, including PHA structure–properties relationships, its unique crystalline behaviour, in vivo – in vitro synthesis and degradation, and PHA-graft-copolymers.Key words: poly(hydroxyalkanoate), PHA, poly(β-hydroxybutyrate), PHB, biopolymers, bacterial polyester, random copolymers, polymer single crystals, graft copolymers.
Gold-catalyzed efficient regioselective addition of arenes to allenes
Authors: Skouta Rachid , Li Chao-Jun
Published: May 2008

An efficient addition of arenes to allenes is developed by using a combination of gold and silver catalysts. The arene addition takes place exclusively at the terminal allenic carbon leading to a highly regioselective carbon-carbon bond formation.Key words: arenes, allenes, gold, hydroarylation, regioselective, silver.
Hepatocyte nuclear factor-4α is a central transactivator of the mouse Ntcp gene
Authors: Geier Andreas , Martin Ina V. , Dietrich Christoph G. , Balasubramaniyan Natarajan , Strauch Sonja , Suchy Frederick J. , Gartung Carsten , Trautwein Christian , Ananthanarayanan Meenakshisundaram
Published: May 2008

Sodium taurocholate cotransporting polypeptide (Ntcp) is the major uptake system for conjugated bile acids. Deletions of hepatocyte nuclear factor (HNF)-1α and retinoid X receptor-α:retinoic acid receptor-α binding sites in the mouse 5′-flanking region corresponding to putatively central regulatory elements of rat Ntcp do not significantly reduce promoter activity. We hypothesized that HNF-4α, which is increasingly recognized as a central regulator of hepatocyte function, may directly transactivate mouse ( mNtcp). A 1.1-kb 5′-upstream region including the mouse Ntcp promoter was cloned and compared with the rat promoter. In contrast to a moderate 3.5-fold activation of mNtcp by HNF-1α, HNF-4α cotransfection led to a robust 20-fold activation. Deletion analysis of mouse and rat Ntcp promoters mapped a conserved HNF-4α consensus site at −345/−326 and −335/−316 bp, respectively. p-475bp mNtcpLUC is not transactivated by HNF-1α but shows a 50-fold enhanced activity upon cotransfection with HNF-4α. Gel mobility shift assays demonstrated a complex of the HNF-4α-element formed with liver nuclear extracts that was blocked by an HNF-4α specific antibody. HNF-4α binding was confirmed by chromatin immunoprecipitation. Using Hepa 1–6 cells, HNF-4α-knockdown resulted in a significant 95% reduction in NTCP mRNA. In conclusion, mouse Ntcp is regulated by HNF-4α via a conserved distal cis-element independently of HNF-1α.
Targeted disruption of theLasp-1gene is linked to increases in histamine-stimulated gastric HCl secretion
Authors: Chew Catherine S. , Chen Xunsheng , Bollag Roni J. , Isales Carlos , Ding Ke Hong , Zhang Han
Published: May 2008

Lasp-1 (LIM and SH3 domain protein 1) is a multidomain actin-binding protein that is differentially expressed within epithelial tissues and brain. In the gastric mucosa, Lasp-1 is highly expressed in the HCl-secreting parietal cell, where it is prominently localized within the F-actin-rich subcellular regions. Histamine-induced elevation of parietal cell [cAMP]iincreases Lasp-1 phosphorylation, which is correlated with activation of HCl secretion. To determine whether Lasp-1 is involved in the regulation of HCl secretion in vivo, we generated a murine model with a targeted disruption of the Lasp-1 gene. Lasp-1-null mice had slightly lower body weights but developed normally and had no overt phenotypic abnormalities. Basal HCl secretion was unaffected by loss of Lasp-1, but histamine stimulation induced a more robust acid secretory response in Lasp-1-null mice compared with wild-type littermates. A similar effect of histamine was observed in isolated gastric glands on the basis of measurements of accumulation of the weak base [14C]aminopyrine. In addition, inhibition of the acid secretory response to histamine by H2 receptor blockade with ranitidine proceeded more slowly in glands from Lasp-1-null mice. These findings support the conclusion that Lasp-1 is involved in the regulation of parietal HCl secretion. We speculate that cAMP-dependent phosphorylation of Lasp-1 alters interactions with F-actin and/or endocytic proteins that interact with Lasp-1, thereby regulating the trafficking/activation of the H+, K+-ATPase (proton pump).
Vitamin D derivatives acutely reduce endothelium-dependent contractions in the aorta of the spontaneously hypertensive rat
Authors: Wong Michael S. K. , Delansorne R. , Man Ricky Y. K. , Vanhoutte Paul M.
Published: May 2008

The available evidence suggests that vitamin D has cardiovascular effects besides regulating calcium homeostasis. To examine the effect of 1,25-dihydroxyvitamin D3, the major metabolite of vitamin D, on endothelium-dependent contractions, aortic rings of spontaneously hypertensive rats (SHR) were suspended in organ chambers for isometric force measurements. Rings were incubated with Nω-nitro-l-arginine methyl ester (l-NAME) and then exposed to increasing concentrations of acetylcholine, ATP, or the calcium ionophore to trigger contractions. This was done in the absence or presence of 1,25-dihydroxyvitamin D3. The release of prostacyclin after acetylcholine or A-23187 stimulation was also measured. The cytosolic-free calcium concentration was measured by confocal microscopy after incubation with the fluorescent dyes fluo-4 and fura red. The presence of vitamin D receptors was confirmed using immunohistochemistry. Acetylcholine- and ATP-induced endothelium-dependent contractions were significantly reduced compared with those obtained in the absence of the drug. This effect was not present if A-23187 was used as an agonist. The acetylcholine- but not the A-23187-induced release of prostacyclin was reduced by the acute administration of 1,25-dihydroxyvitamin D3. Exposure to 1,25-dihydroxyvitamin D3 reduced the increase in cytosolic-free calcium concentration caused by acetylcholine but not by A-23187 in cells. Vitamin D receptors were densely distributed in the endothelium. Inecalcitol (19-nor-14-epi-23-yne-1,25-dihydroxyvitamin D3), a synthetic analog of vitamin D, caused a comparable depression of endothelium-dependent contractions as 1,25-dihydroxyvitamin D3. These results demonstrate that vitamin D3 modulates vascular tone by reducing calcium influx into the endothelial cells and hence decreasing the production of endothelium-derived contracting factors.
The involvement of norepinephrine, neuropeptide Y, and nitric oxide in the cutaneous vasodilator response to local heating in humans
Authors: Hodges Gary J. , Kosiba Wojciech A. , Zhao Kun , Johnson John M.
Published: May 2008

Presynaptic blockade of cutaneous vasoconstrictor nerves (VCN) abolishes the axon reflex (AR) during slow local heating (SLH) and reduces the vasodilator response. In a two-part study, forearm sites were instrumented with microdialysis fibers, local heaters, and laser-Doppler flow probes. Sites were locally heated from 33 to 40°C over 70 min. In part 1, we tested whether this effect of VCN acted via nitric oxide synthase (NOS). In five subjects, treatments were as follows: 1) untreated; 2) bretylium, preventing neurotransmitter release; 3) NG-nitro-l-arginine methyl ester (l-NAME) to inhibit NOS; and 4) combined bretylium + l-NAME. At treated sites, the AR was absent, and there was an attenuation of the ultimate vasodilation ( P < 0.05), which was not different among those sites ( P > 0.05). In part 2, we tested whether norepinephrine and/or neuropeptide Y is involved in the cutaneous vasodilator response to SLH. In seven subjects, treatments were as follows: 1) untreated; 2) propranolol and yohimbine to antagonize α- and β-receptors; 3) BIBP-3226 to antagonize Y1 receptors; and 4) combined propranolol + yohimbine + BIBP-3226. Treatment with propranolol + yohimbine or BIBP-3226 significantly increased the temperature at which AR occurred ( n = 4) or abolished it ( n = 3). The combination treatment consistently eliminated it. Importantly, ultimate vasodilation with SLH at the treated sites was significantly ( P < 0.05) less than at the control. These data suggest that norepinephrine and neuropeptide Y are important in the initiation of the AR and for achieving a complete vasodilator response. Since VCN and NOS blockade in combination do not have an inhibition greater than either alone, these data suggest that VCN promote heat-induced vasodilation via a nitric oxide-dependent mechanism.
MRI-Based Score for Acute Basilar Artery Thrombosis
Authors: Renard D. , Landragin N. , Robinson A. , Brunel H. , Bonafe A. , Heroum C. , Milhaud C.
Published: May 2008

Background: Intra-arterial thrombolysis may reduce mortality in acute basilar artery (BA) occlusion. We wanted to identify an easy-to-use pre-treatment MR-based predictor of clinical outcome in patients with acute BA occlusion treated with IAT. Methods: We analyzed 16 patients with acute BA occlusion prospectively. Vascular risk factors, as well as National Institutes of Health Stroke Scale (NIHSS) and Glasgow Coma Scale (GCS) scores were recorded on admission, together with a 10-point semiquantitative score reflecting the number of acute ischaemic brain lesions on diffusion-weighted imaging. The recanalization grade was evaluated by angiography. The clinical outcome, using the modified Rankin scale (mRs), was measured 3 months later. Results: Risk factors, NIHSS and GCS scores, time from symptom onset to treatment, recanalization rate, outcome and outcome predictors (such as age, NIHSS and GCS scores) were comparable to other studies. Haemorrhagic transformation of infarction occurred in 2 patients (12.5%). We found that a high lesion score was an additional predictor of poor outcome (p = 0.026). Conclusions: In patients with acute BA occlusion, treated with intra-arterial recombinant tissue plasminogen activator, a high number of acute ischaemic lesions, based on diffusion-weighted imaging, is a predictor of poor clinical outcome.
Value of Overnight Monitoring of Intracranial Pressure in Hydrocephalic Children
Authors: Schuhmann Martin U. , Sood Sandeep , McAllister James P. , Jaeger Matthias , Ham Steven D. , Czosnyka Zofia , Czosnyka Marek
Published: May 2008

Objective: Exaggerated nocturnal intracranial pressure (ICP) dynamics are commonly observed in hydrocephalic children with a compromise of CSF compensatory reserve capacity. Successful shunting restores this cerebrospinal reserve. We used ICP overnight monitoring combined with positional maneuvers in complex hydrocephalic children with a suspected shunt malfunction for the assessment of shunt function. Methods: In 32 hydrocephalic children, we performed 65 computerized overnight recordings and 25 positional maneuvers. Baseline ICP was considered abnormal if it exceeded the operating pressure of the shunt by more than 2.5 mm Hg. The maximum ICP (normal = <25 mm Hg), RAP coefficient (the correlation coefficient between pulse amplitude and mean intracranial pressure, which indicates pressure volume compensatory reserve; normal = <0.6), magnitude of slow waves (SLOW) and ICP pulse amplitude (AMP) were calculated for each night. Results: Using baseline ICP, maximum ICP and RAP, 19 recordings were classified as ‘normal’ (group 1), 13 as ‘questionable’ (group 2), and 33 as ‘pathological’ (group 3) indicating shunt dysfunction or active hydrocephalus. ICP, AMP, RAP and SLOW were significantly different between groups and significantly elevated in group 3 compared to group 1. Positional tests identified shunt overdrainage in 5 of 25 occasions. In patients of group 1, who underwent revision, shunts turned out to be functional. All patients of group 3 eventually underwent shunt revision with improvement of symptoms thereafter. Conclusion: Computerized ICP monitoring can benefit the assessment of shunt function, and can accurately characterize the status of CSF compensation in shunted children with a complex presentation.
Immunocytochemical Characterization of Astrocytosis along the Spinal Cord of Loop-Tail/Curly-Tail Mice with Myelomeningocele
Authors: Reis Joaquim L. , Correia-Pinto Jorge , Monteiro Mariana P. , Costa Madalena , Ribeiro Alexandrina , Hutchins Grover M.
Published: May 2008

Background: The neurological deficits of myelomeningocele (MMC) have been attributed both to a primary neurulation defect and to a secondary injury of the placode in the intrauterine environment. Since astrocytes are involved in glial scar formation after spinal cord injury, the characterization of astrocyte density along the spinal cord upstream of the MMC can be used as a surrogate marker of the extension of the injury beyond the MMC. Methods: The curly-tail/loop-tail murine model was applied to obtain newborn mice with MMC. The astrocyte density and topography both at the MMC placode level and at the upper segments of the spinal cord was characterized by immunolabeling using the anti-glial fibrillary acidic protein antibody. This was followed by a qualitative evaluation of immunolabeled cells and morphometric analysis of the samples. Results: The topography of astrocytes in the spinal cord of MMC newborn mice was compared with that of newborn control mice (without spina bifida aperta) (n = 8/group). The anti-glial fibrillary acidic protein immunoreactivity was significantly increased in the MMC samples in comparison with the normal spinal cord, indicating the presence of an astrocytic response. Increased astrocytosis was also observed in the transitional area located above the MMC. The astrocytosis decreased progressively along the MMC spinal cord until matching the pattern of the control spinal cords. This transitional area involved a segment of the spinal cord with a length of 240 µm in the newborn mouse. Conclusions: MMC newborn mice show spinal cord injury that is located upstream of the exposed placode and is characterized by proliferation of astrocytes. This finding offers further support for the hypothesis of a tethering mechanism as part of the spinal cord injury observed in MMC newborns.
Pediatric Intracranial Aneurysms: An Institutional Experience
Authors: Vaid Vivek Kumar , Kumar Raj , Kalra Samir Kumar , Mahapatra Ashok Kumar , Jain Vijendra Kumar
Published: May 2008

Introduction: Intracranial aneurysms are extremely uncommon in the pediatric population. Their epidemiology is poorly understood, and certain features make them unique. In our study we analyzed pediatric intracranial aneurysm patients to gain an insight into the epidemiology, clinicoradiological profile and outcome. Material and Methods: Out of 36 children (≤18 years of age; male:female ratio = 1.076:1; mean age 13.19 ± 3.72 years, age range 5–18 years) presenting with subarachnoid hemorrhage (SAH; n = 33; 91.67%) and mass effect (n = 3; 8.33%), 27 who were positive on digital subtraction angiography and treated for intracranial aneurysms between January 1991 and February 2007 were included in this study. Results: At presentation, the majority (n = 21) of the pediatric intracranial patients showed a good grade, and 23 (85.18%) presented with SAH. Sudden severe headache (n = 19; 70.37%) and loss of consciousness (n = 14; 51.85%) were the most common symptoms, and meningeal signs (n = 18; 66.66%) most commonly elicitable. There were 7 patients with giant aneurysms and 8 patients with posterior circulation aneurysms. Internal carotid artery (ICA) bifurcations (n = 6; 18.18%) followed by middle cerebral artery (MCA) bifurcations (n = 4; 12.12%) were the most common sites. At a mean follow-up of 18.67 ± 10.85 months (range 1–42 months), there were 21 (77.77%) patients with favorable outcome and 3 patients died. Conclusions: Intracranial aneurysms in children commonly present with SAH; there is a male predominance, and ICA bifurcations followed by MCA bifurcations are the most common sites. The incidence of posterior circulation aneurysms and giant aneurysms is higher as compared to adults. The pediatric patients present with better grades and have better overall surgical results.
Pure Eye Muscle Involvement in Endocrine Orbitopathy
Authors: Gerlach Marion , Ferbert Andreas
Published: May 2008

We present a long-term follow-up examination concerning patients with isolated extra-ocular muscle involvement in thyroid-related orbitopathy. Within the previous 13 years we observed 7 patients with endocrine orbitopathy and marked myopathy of the extra-ocular muscles. Five of these patients had no detectable proptosis, 2 of them showed a minimal unilateral proptosis. Five patients showed elevated thyroid-stimulating hormone (TSH) receptor auto-antibodies and 6 patients a marked swelling of the extra-ocular eye muscles on CT or MRI scans. One patient had elevated antibodies against thyroid peroxidase and against thyroglobulin and normal TSH receptor auto-antibodies. Four of 7 patients underwent clinical and radiological follow-up examination 1–9 years later. In 3 of these 4 patients, the clinical syndrome had completely resolved. None of the patients had developed any proptosis. The swelling of the eye muscles on radiological imaging had at least partially resolved. We conclude from our results that apart from the frequent subtype of endocrine orbitopathy with predominant proptosis there is a separate subtype in which proptosis neither exists initially nor develops in the further course. Probably these subtypes have a specific immunological antibody profile although they do not differ concerning the thyroid-stimulating antibodies.
Clock-Drawing Test Performance in the Normal Elderly and Its Dependence on Age and Education
Authors: von Gunten Armin , Ostos-Wiechetek Marzanna , Brull Juliette , Vaudaux-Pisquem Ines , Cattin Sylvie , Duc René
Published: May 2008

Objective: The main objective was to assess the relative frequency and types of errors on the clock-drawing test (CDT) in normal elderly subjects, and the dependence of their CDT performance upon their age and education. Method: The CDT performance of 242 normal elderly subjects, stratified according to age and education, was analyzed using both an absolute error count and a modified scoring sheet derived from 2 scales. Results: Normal elderly subjects (average age: 73.4 ± 8.4 years; mean Mini-Mental State Examination score: 27.7 ± 1.6) often have problems placing figures on the clock face and differentiating the clock hands correctly. The absolute number of errors increases with age and decreases with formal school education. A cumulative effect of both high age and a low level of school education yields substantially inferior scores, on the modified scale used, in comparison with younger subjects and those with higher levels of education. Conclusion: The frequent errors made by normal elderly subjects, and a combined negative influence of high age and low education level, suggest caution when interpreting the significance of CDT performance in the elderly.
Improved Cerebral Vasoreactivity following Percutaneous Transluminal Angioplasty with Stenting of High-Grade Internal Carotid Artery Stenosis
Authors: Brčić Iva , Horner Susanna , Thaler Daniela , Demarin Vida , Klein Günther Erich , Niederkorn Kurt
Published: May 2008

Background: The aim of this study was to assess the effects of percutaneous transluminal angioplasty with stenting on cerebral vasoreactivity in carotid stenosis (CS). Methods: We studied the changes in the middle cerebral artery using transcranial Doppler and the breath-holding index (BHI) after hypercapnia in 33 patients with CS (15 symptomatic, 18 asymptomatic) before and 1 day and 1 month after stenting. Results: One day after stenting, the BHI significantly increased (p < 0.01) on the previously stenotic side in all patients. One month after stenting, the BHI was significantly higher on the contralateral side of asymptomatic (p < 0.05) and symptomatic patients (p < 0.01). Conclusion: Percutaneous transluminal angioplasty with stenting results in increasing improvement close to normalization of impaired cerebral vasoreactivity in patients with symptomatic and asymptomatic high-grade CS.
The Genetics of Carotid Dissection: Meta-Analysis of a MTHFR/C677T Common Molecular Variant
Authors: McColgan Peter , Sharma Pankaj
Published: May 2008

Background and Purpose: Carotid dissection is a recognized cause of stroke. An association has been reported between carotid dissection and elevated homocysteine levels. Homocysteine levels are partly determined by a thermolibile form of methyltetrahydrofolate reductase (MTHFR) which has a common C677T single nucleotide polymorphism (SNP). We sought to undertake a comprehensive genetic meta-analysis of this SNP and its association with carotid dissection. Methods: All case-control studies evaluating MTHFR/C677T in carotid dissection were identified. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) using both fixed and random effects were determined for both dominant and recessive genetic models. Analyses were also undertaken to compare the effects of the homogenous forms of MTHFR/C677T. Results: Four manuscripts analyzing a total of 420 individuals (183 cases and 237 controls) were identified. The pooled OR for the dominant MTHFR/T677 model was 1.36 (95% CI 0.89–2.08; p = 0.16) while the pooled OR for the recessive TT model was 1.07 (95% CI 0.61–1.89; p = 0.81). To ensure a subtle recessive effect was not being masked by the inclusion of the heterozygous genotype, comparison of the CC and TT genotypes in cases against controls was undertaken but no significant association was observed (OR 0.73; 95% CI 0.38–1.40; p = 0.34). Conclusions: Our data does not support an association between the MTHFR/C677T molecular variant and carotid dissection. As this SNP accounts for the majority of the genetic variance of homocysteine levels, our data suggests that homocysteine is unlikely to play a major role in this condition.
Non-Random Distribution and Sensory Functions of Primary Cilia in Vascular Smooth Muscle Cells
Authors: Lu C.J. , Du H. , Wu J. , Jansen D.A. , Jordan K.L. , Xu N. , Sieck G.C. , Qian Q.
Published: May 2008

Although primary cilia are increasingly recognized to play sensory roles in several cellular systems, their role in vascular smooth muscle cells (VSMCs) has not been defined. We examined in situ position/orientation of primary cilia and ciliary proteins in VSMCs and tested the hypothesis that primary cilia of VSMCs exert sensory functions. By immunofluorescence and electron microscopic imaging, primary cilia of VSMCs were positioned with their long axis aligned at 58.3° angle in relation to the cross-sectional plane of the artery, projecting into the extracellular matrix (ECM). Polycystin-1, polycystin-2 and α3- and β1-integrins are present in cilia. In scratch wound experiments, the majority of cilia were repositioned to the cell-wound interface. Such repositioning was largely abolished by a β1-integrin blocker. Moreover, compared to non-ciliated/deciliated cells, ciliated VSMCs showed more efficient migration in wound repair. Lastly, when directly stimulated with collagen (an ECM component and cognate ligand for α3β1-integrins) or induced ciliary deflection, VSMCs responded with a rise in [Ca2+]i that is dependent on the presence of cilia. Taken together, primary cilia of VSMCs are preferentially oriented, possess proteins critical for cell-ECM interaction and mechanosensing and respond to ECM protein and mechanical stimulations. These observations suggest a role for primary cilia in mechanochemical sensing in vasculature.
Treatment of Septic Patients with an Arginine-Based Endotoxin Adsorber Column Improves Hemodynamics and Reduces Oxidative Stress: Results of a Feasibility Study
Authors: Umgelter Andreas , Reindl Wolfgang , Lutz Jens , Kreymann Bernhard , Ronco Claudio , Huber Wolfgang , Frank Helga , Schmid Roland M. , Heemann Uwe
Published: May 2008

Background: Mortality of severe sepsis and septic shock is unacceptably high. Adsorptive removal of endotoxin may interrupt the inflammatory cascade triggered by lipopolysaccharide. Methods: Prospective feasibility study with plasma separation and adsorption (PSA) treatment using a novel arginine-coated adsorber column was performed in a tertiary care gastroenterological intensive care unit. Results: 10 patients with severe sepsis/septic shock (median APACHE II score: 27, hospital mortality 40%) were treated with PSA on 5 consecutive days. There were no serious adverse events. No patient died during the treatment period. During treatment sessions, mean arterial pressure and cardiac power index increased while vasopressors could be reduced. Advanced oxidation protein products and in vitro pro- apoptotic activity of plasma decreased. We could not demonstrate any changes in endotoxin levels. Conclusions: PSA resulted in a reduction of indicators of oxidative stress and pro-apoptotic activity of the plasma and an improvement in hemodynamic parameters, suggesting increased myocardial contractility and reduced septic vasodilation.
Geographic patterns of chromosomal variation in South American marsh rats, Holochilus brasiliensis and H. vulpinus
Authors: Nachman M.W.
Published: May 2008

Karyotypes were prepared from 146 individuals, representing nine populations evenly spaced along a 2,000-km north-south transect in Paraguay and Argentina, to determine the nature, extent, and pattern of chromosomal variation in Holochilus brasiliensis chacarius and H. vulpinus. Two distinct patterns of chromosomal variation characterized these two species. In H. brasiliensis, the diploid number (2n) ranged from 48 to 56 and the nombre fundamental (NF) from 57 to 63. Four classes of chromosomal variation were found in populations of H. brasiliensis: whole-arm Robertsonian (Rb) translocations, including Rb changes with monobrachial homology, variation in the number and kind of supernumerary (B) chromosomes, centromeric rearrangements (putative pericentric inversions), and variation in the amount of euchromatin. The amount of structural variation was uniformly high in all populations of H. brasiliensis sampled, and all rearrangements appeared to be in Hardy-Weinberg proportions, corroborating the hypothesis that chromosomal rearrangements are not strongly underdominant in this species. In H. vulpinus, 2n ranged from 35 to 39 and NF from 57 to 61. Two classes of variation were found in this species: variation in the number, but not the kind, of supernumerary chromosomes and variation in the amount of euchromatin.
Meiotic studies of Robertsonian polymorphisms in the South American marsh rat, Holichilus brasiliensis
Authors: Nachman M.W.
Published: May 2008

Meiosis was studied in male South American marsh rats (1) to help clarify the mechanisms that allow unusually high levels of Robertsonian (Rb) polymorphisms to be maintained in wild populations of these animals and (2) to test competing assumptions in two distinct models of chromosomal speciation. In both simple Rb heterozygotes and Rb heterozygotes with monobrachial homology, no univalency was observed in prophase I or metaphase I. Rates of nondisjunction were uniformly low (<10%) and did not differ significantly among any of the animals studied, regardless of karyotype and in contrast to the frequency of nondisjunction in other mammalian species. Robertsonian heterozygotes exhibited significantly more chiasmata than did homozygotes, largely owing to an increase in the number of terminally located chiasmata. There was a significant bias favoring the transmission of two acrocentrics over the single metacentric for some Rb rearrangements in the heterozygous state. In addition, the frequency of sex-chromosome univalency increased with increasing Rb heterozygosi-ty, although the ratio of X- and Y-bearing secondary spermatocytes did not differ significantly from 1:1, and no secondary spermatocytes were observed that were nullisomic or disomic for an X or Y chromosome.
Localization of four human chromosome 21 genes — SOD1, ETS2, IFNAR, and CBR — to two different chromosomes in the marsupial species Macropus eugenii
Authors: Brookes S. , Maccarone P. , de Haan J.B. , Tymms M. , Forrest G.L. , Marshall Graves J.A. , Kola I.
Published: May 2008

We have mapped the chromosomal location of four genes previously assigned to human chromosome 21—Cu/Zn superoxide dismutase (SOD1), the protooncogene ETS2, the interferon α/β receptor gene (IFNAR), and the carbonyl reduc-tase gene (CBR)—in the tammar, Macropus eugenii. The genes are localized on two separate autosomes: SOD1 and CBR map to chromosome 7 and ETS2 and IFNAR map to chromosome 3 or 4. These results provide the first example of asynteny between SOD1/CBR and ETS2/IFNAR in a mammalian species. The results suggest that either this synteny group has been disrupted in the marsupial lineage or, alternatively, the genes located on human chromosome 21 may have been joined after the marsupials diverged from the eutherian mammals some 130–150 million years ago.
Chromosomal rearrangements in rock wallabies, Petrogale (Marsupialia: Macropodidae)
Authors: Eldridge M.D.B. , Johnston P.G. , Close R.L.
Published: May 2008

G-banding has demonstrated the presence of a conserved (2n = 22) chromosome complement in the macropod genus Thylogale and in some Petrogale species.This plesiomorphic karyotype consists of acrocentric chromosomes 1, 2, 5, 6, 8, 9, and 10; submetacentric chromosomes 3 and 4; and a metacentric chromosome 7. It should now be possible to relate the G-banding patterns of all other Petrogale species to this plesiomorphic complement and thereby determine the number and types of changes that have occurred during the course of chromosome evolution in Petrogale. It is hypothesised that this 2n = 22 complement is plesiomorphic for all macropodids.
Chromosomal rearrangements in rock wallabies, Petrogale (Marsupialia: Macropodidae)
Authors: Eldridge M.D.B. , Johnston P.G. , Lowry P.S.
Published: May 2008

G-banded metaphase preparations of cultured fibroblasts were used to construct the karyotypes of Petrogale brachyotis (2n = 18) and P. concinna (2n = 16). The two karyotypes differ significantly from the plesiomorphic karyotype of the genus and from those of all other Petrogale species examined. Petrogale brachyotis and P. concinna are characterised by three synapomorphies: a 1–10 centric fusion, a 3a-6 centric fusion, and a submetacentric chromosome 2 (2s). Both species also possess autapomorphies. Petrogale brachyotis is characterised by submetacentric chromosomes 5 (5s) and 4 (4sm), whereas P. concinna is characterised by a 5–9 centric fusion and a submetacentric chromosome 8 (8m). The 2s, 5s, 4sm, and 8m chromosomes all appear to be derived from their plesiomorphic homologs by centromeric transpositions. Although the rate of chromosome evolution varies considerably in Petrogale, the genus clearly exhibits karyotypic orthoselection, with all the autosomal rearrangements identified being either centric fusions or centromeric transpositions. This study also illustrates the potential for convergent evolution in chromosomally diverse groups and demonstrates the importance of G-banding studies for accurate identification of chromosome rearrangements.
Synapsis, recombination, and meiotic segregation in the mesquite lizard, Sceloporus grammicus, complex
Authors: Reed K.M. , Sites Jr. J.W. , Greenbaum I.F.
Published: May 2008

Chromosomal pairing and recombination were analyzed in male specimens of Sceloporus grammicus heterozygous for a large pericentric inversion of macrochromosome 4. Analysis of silver-stained synaptonemal complexes (SCs) in surface-spread nuclei revealed that homologously paired inversion loops were not formed. Synapsis of the inverted segments proceeded directly to nonhomologous straight pairing. In some nuclei, this resulted in a configuration that could not be distinguished from homozygous bivalents of similar size. Examination of Giemsa- and silver-stained diakinetic nuclei indicated that crossing-over was limited to the noninverted (homologous) portion of the heteromorphic bivalent. Analysis of secondary spermatocytes (metaphase II configurations) revealed normal disjunction and balanced segregation of the elements of the heteromorphic bivalent. These observations indicate that the inversion heteromorphism does not lead to the production of unbalanced gametes.
Linkage of two enzyme loci in the fish genus Poecilia (Teleostei: Poeciliidae)
Authors: Narine K.M. , Kallman K.D. , Walter R.B. , Morizot D.C.
Published: May 2008

The linkage of loci coding for glucose-6-phosphate dehydrogenase (G6PD) and phosphogluconate dehydrogenase (PGD) is described in fish of the genus Poecilia (Teleostei: Poeciliidae) and designated Poecilia linkage group I. These two loci were shown to assort independently from six other informative markers (peptidase S, malate dehydrogenase 2 [soluble], man-nose phosphate isomerase, parvalbumin 2, phosphoglucomutase, and glyceraldehyde-3-phosphate dehydrogenase 2) within the limits of the data obtained. Data for the linkage analyses were generated by scoring starch-gel electrophoretic phenotypes of the eight loci in reciprocal backcross hybrids obtained from matings between Poecilia perugiae and P. vittata. The linkage χ2 for G6PD-PGD locus pairs was significant (P < 0.001) in all reciprocal backcross hybrid broods (22.7 % recombinants in the combined data), indicating linkage in both parental species. The linkage of G6PD and PGD in gene maps of the poeciliid genera Xiphophorus and Poeciliopsis documents homology of this linkage within the family. Linkages in salmonid and centrarchid fishes suggest conservation of this linkage group in most or all teleosts. The six additional independently assorting loci have been assigned to independent linkage groups in Xiphophorus; thus, no example of poeciliid linkage group divergence has yet been identified.
Isolation of new probes from Xq12→q13: an example of the screening of reference libraries with Alu-PCR products from radiation hybrids
Authors: Muscatelli F. , Monaco A.P. , Goodfellow P.N. , Hors-Cayla M.C. , Lehrach H. , Fontes M.
Published: May 2008

In order to isolate new probes from the juxtacentromeric region of the long arm of the human X chromosome, we usedAlu-mediated polymerase chain reaction (Alu-PCR) products as probes to directly screen a chromosome X-speciñc gridded cosmid library. These Alu-PCR products were synthesized from radiation hybrids containing the loci DXS159, PGK1 and PGK1P1. This approach allowed us to select 18 cosmids capable of hybridizing with at least two Alu-PCR products. Four cosmids hybridized to more than three Alu-PCR products. Three of these four cosmids were contiguous, and the fourth was independent. Two cosmids that hybridized with two Alu-PCR products were further characterized. Physical mapping indicated that all of these clones are located in the expected region on Xq, confirming the validity of our approach.
Localization of the human urate oxidase gene (UOX) to 1p22
Authors: Yeldandi A.V. , Patel Y.D. , Liao M. , Kao F.T. , Rao M.S. , Reddy J.K. , Le Beau M.M.
Published: May 2008

The human urate oxidase (E.C. 1.7.3.3) gene, UOX, is assigned to chromosome 1 by Southern analysis of human × hamster cell hybrids. Using fluorescent in situ hybridization, we have mapped this gene to 1p22.
Chromosomal localization of the rat Harvey-ras-l gene (HRAS) by in situ hybridization
Authors: Gollahon L.S. , Aldaz C.M.
Published: May 2008

The rat Harvey-ras-1 protooncogene (HRAS) has previously been assigned to rat chromosome 1. In this study we further refine its localization to region 1q41→q42 through the use of fluorescent in situ hybridization.
Chromosomal assignments of genes for rat glutathione S-transferase Ya (GSTA1) and Yc summits (GSTA2)
Authors: Yamada T. , Muramatsu Y. , Yasue M. , Agui T. , Yamada J. , Matsumoto K.
Published: May 2008

Chromosomal assignments of genes for rat glutathione S-transferase Ya (GSTA1) and Yc subunits (GSTA2) were performed by Southern blot analyses of somatic cell hybrid DNAs. GSTA1 and GSTA2 were assigned to rat chromosomes 8 and 9, respectively.
New gene assignments to rabbit chromosomes; implications for chromosome evolution
Authors: Lemieux N. , Dutrillaux B.
Published: May 2008

The genes for SOD1 and SOD2 (superoxide dismutases 1 and 2), RBI (retinoblastoma), TYMS (thymidylate synthase), and TKl (thymidine kinase) were mapped by in situ hybridization using biotinylated probes to rabbit chromosomes 6, 12, 8, 9, and 19, respectively. This confirms their proposed homoeologies with human chromosomes 21, 6, 13, 18, and 17, respectively, and provides additional information on the modification of these chromosomes during evolution.
The gene map of the pig (Sus scrofa domestica L.): a review
Authors: Echard G. , Milan D. , Yerle M. , Lahbib-Mansais Y. , Gellin J.
Published: May 2008

A review of the present status of the porcine gene map is given with references. A total of 84 loci have now been studied, and genes have been assigned to 17 chromosomes. Among them, six chromosomes are defined by only one marker. No loci have been attributed yet to three chromosomes.
Microchromosomal assignment of the chicken ovotransferrin and adenylate kinase genes
Authors: Dominguez-Steglich M. , Jeltsch J.M. , Nakazawa A. , Schmid M.
Published: May 2008

Ovotransferrin, an egg-white protein implicated in the transfer of trace elements from the hen oviduct to the developing avian embryo, and cytosolic adenylate kinase, an essential enzyme involved in the interconversion of adenine nucleotides in energetically active tissues, have been mapped to two separate chicken microchromosomes by fluorescent in situ hybridization. Considering present and previous data, the possibility of loss of intron material resulting in the compactation of genes in chicken microchromosomes is briefly discussed.
Localization of the βA4-crystallin gene (CRYBA4) on human chromosome 22 in the region q11.2→q13.1
Authors: van Rens G.L.M. , Geurts van Kessel A.H.M. , Bloemendal H.
Published: May 2008

The chromosomal localization of the human gene (CRYBA4) coding for the eye lens protein βA4-crystallin has been carried out using a nearly full-length cDNA clone encoding bovine βA4-crystallin. A panel of 21 human-mouse or human-hamster hybrid cell lines derived from different parental combinations was characterized with respect to the human chromosomal content and the presence of well established human chromosome-specific markers. These panels were screened for the presence of CRYBA4 using the bovine cDNA clone as a probe. A 100 percent concordance was observed between the presence or absence of the CRYBA4 and human chromosome 22 indicating that the gene resides on this chromosome. By using cell hybrids containing translocated chromosome 22 segments, the localization could be refined to the region 22q11.2→q13.1.
Assignment of the rabbit genes for α (PHKA) and β (PHKB) phosphorylase kinase subunits
Authors: Debecker A. , Martin-DeLeon P.A.
Published: May 2008

The chromosomal locations of the rabbit genes for the α and β subunits of phosphorylase kinase (PHKA and PHKB) were determined by in situ hybridization using rabbit cDNA probes. Our results localize PHKA to the X chromosome at the proximal end of the long arm, near the centromere, and PHKB to the same location on chromosome 5. These assignments support previously reported homoeologies of rabbit and human chromosomes.
Characterization of yeast artificial chromosomes containing interleukin genes on human chromosome 5
Authors: Stock W. , Chandrasekharappa S.C. , Neuman W.L. , Le Beau M.M. , Brownstein B.H. , Westbrook C.A.
Published: May 2008

To understand better the organization and linkage of the interleukin genes, IL4 and IL5, we prepared long-range restriction maps of five yeast artificial chromosomes (YACs) containing IL5. We determined that IL4 and IL5 are within 100–170 kb, and that the regions surrounding these genes contain several GC-rich areas. Fluorescence in situ chromosomal analysis demonstrated that three of the five YAC clones contain non-contiguous genomic sequences originating from multiple human chromosomes.
The gene for receptor-like protein tyrosine phosphatase (PTPRB) is assigned to chromosome 12q15→q21
Authors: Harder K.W. , Anderson L.L. , Duncan A.M.V. , Jirik F.R.
Published: May 2008

Using a cDNA probe, the gene encoding the human receptor-like protein tyrosine phosphatase (PTPRB) was localized by in situ hybridization to chromosome 12q15→q21.
Comparative gene mapping in the species Muntiacus muntjac
Authors: Levy H.P. , Schultz R.A. , Cohen M.M.
Published: May 2008

An extreme case of chromosomal evolution is presented by the two muntjac species Muntiacus muntjac (Indian muntjac, 2n = 6 [females], 7 [males]) and M. reevesi (Chinese muntjac, 2n = 46). Despite disparate karyotypes, these phenotypically similar species produce viable hybrid offspring, indicating a high degree of DNA-level conservation and genetic relatedness. As a first step toward development of a comparative gene map, several Indian muntjac homologs of known human type I anchor loci were mapped. Using flow-sorted, chromosome-specific Southern hybridization techniques, homologs of the protein kinase C β polypeptide (PRKCB1) and the DNA repair genes ERCC2 and XRCC1 have been assigned to Indian muntjac chromosome 2. The male-specific ZFY gene was presumptively mapped to Indian muntjac chromosome Y2. Ultimate generation of a comparative physical map of both Indian and Chinese muntjac chromosomes will prove invaluable in the study of mammalian karyotype evolution.
Aberrant Myc expression in the murine trisomy 15 syndrome is correlated with prolonged proliferation in spongiotrophoblast cells of the placenta
Authors: Hirning-Folz U. , Winking H. , Hameister H.
Published: May 2008

In the mouse the protooncogene Myc is localized to Chromosome 15. Embryos with trisomy 15 (Ts15) are severely retarded and die in utero at an early stage. The placenta of these embryos shows enlargement of the fetal spongiotrophoblast. In the spongiotrophoblast and giant cells of the normal euploid placenta, Myc expression declines from day 10.5 of gestation onward whereas Myc expression persists at a high level in Ts 15 cells. At the same time these Ts15 cells show prolonged proliferation which consequently leads to the observed enlargement of that tissue layer in Ts15 placentas.