bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of methods of platelet counting in the cat
Authors: Tasker S. , Cripps P. J. , Mackin A. J.
Published: April 2008

Platelet counts were performed in 50 cats presented for diagnostic investigation. For each cat, counts were obtained using a manual haemocytometer method and compared with counts obtained by estimation from a stained blood smear, a QBC VetAutoread analyser, a Zynocyte VS/2000 analyser, impedance automated counts on a Baker System using both EDTA and citrated anticoagulated blood, and use of a Zynostain modified counting chamber kit. None of the methods gave high correlation with the haemocytometer counts. The blood smear estimation of platelet counts had the highest correlation (r = 0–776) and was the only method to have reasonable values for both sensitivity and specificity. With the impedance automated counts, citrated anticoagulated blood had marginally higher correlation than EDTA anticoagulated blood, and the time between blood sampling and platelet count determination had no effect on the count obtained. When in‐house analyser or impedance automated platelet counts are abnormal or not consistent with clinical findings, the authors recommend that a manual platelet count using either haemocytometry or examination of a blood smear is performed.
Malignant seminoma with systemic metastases in a dog
Authors: Takiguchi M. , Iida T. , Kudo T. , Hashimoto A.
Published: April 2008

A three‐year‐old male crossbred dog was presented with multiple cutaneous nodules on the dorsum. Unilateral testicular enlargement ensued. Histopathological examination of testicular tissue and the skin lesions revealed a malignant seminoma. Despite the initiation of adjuvant chemotherapy, the dog died three months later due to systemic metastases of the seminoma to the skin, scrotum, eyes, liver, kidney and peritoneum.
Incomplete humeral condylar fractures in the dog
Authors: Butterworth S. J. , Innes J. F.
Published: April 2008

The details of eight dogs (11 elbows) referred to the authors with lameness relating to elbow pain associated with Incomplete fracture of the humeral condyle were reviewed. In all cases, a diagnosis was reached by radiographic examination, with the pathognomonic feature being a radiolucent line, in the sagittal plane, through the condyle. Treatment involved placement of a transcondylar bone screw with or without bone tunnels being created parallel to this implant. Six dogs (nine elbows) made a complete recovery without subsequent complications.
Vascular hamartoma within the flexor muscles of the left carpus in a dog
Authors: Corzo‐Menéndez N. , White R. N. , Whitelock R. G. , Blunden A. S.
Published: April 2008

A three‐year‐old male bearded collie was presented with a history of left thoracic limb lameness and a fluctuant non‐painful swelling within the flexor tendons of the left carpus. Investigations included ultrasonography, laboratory analysis of fluid aspirated from the lesion and positive contrast radiography. Treatment involved surgical resection of the lesion from the local flexor muscles of the carpus. Histologically, the resected tissue was considered to represent a vascular hamartoma associated with the pronator quadratus muscle.
Treatment of partial seizures and seizure‐like activity with felbamate in six dogs
Authors: Ruehlmann D. , Podell M. , March P.
Published: April 2008

Six dogs with partial seizures or partial seizure‐like activity were treated with the antiepileptic drug felbamate between 1993 and 1998. All dogs had a history and results of diagnostic testing suggestive of either primary (idiopathic) or occult secondary epilepsy. Dogs ranged between four months and eight years of age at the onset of seizure activity. The median time period between onset of the first seizure and the start of felbamate therapy was 3–8 months (range 0–75 to 36 months). Median duration of therapy was nine months (range two to 22 months). All dogs experienced a reduction in seizure frequency after felbamate administration. Median total number of seizures post‐treatment was two (range 0 to 9). Two dogs had an immediate and prolonged cessation of seizure activity. Steady‐state trough serum felbamate concentrations measured at two weeks, and one, 12 and 22 months after the commencement of therapy in four dogs ranged between 13 and 55 mg/litre (median 35 mg/litre). Reversible haematological adverse effects were detected in two dogs, with one dog developing concurrent keratoconjunctivitis sicca. These results suggest that felbamate can be an effective antiepileptic drug without life‐threatening complications when used as monotherapy for partial seizures in the dog.
Diagnosis of cerebellar cortical degeneration in a Scottish terrier using magnetic resonance imaging
Authors: Merwe L. L. van der , Lane E.
Published: April 2008

Primary cerebellar cortical degeneration (CCD), also termed abiotrophy, is the spontaneous premature degeneration of fully differentiated neurological tissue. Cerebellar hypoplasia shares many morphological features with primary CCD, both conditions being characterised by decreased cerebellar size, with reduced numbers of Purkinje and granular cells. CCD has been identified in many canine breeds. This is the first report of the syndrome in a Scottish terrier. The patient presented with mild, gradually progressive ataxia. Survey radiographs of the cervical spine and cerebrospinal fluid (CSF) analysis were normal. CSF distemper andToxoplasmatitres were negative. A diagnosis of cerebellar atrophy was made based on magnetic resonance imaging. The progressive clinical signs suggested cerebellar degeneration rather than hypoplasia. On necropsy, the cerebellum showed macroscopic and microscopic changes consistent with primary CCD.
Identification of focal adenomyosis as a uterine lesion in two dogs
Authors: Stöckun‐Gautschi N. M. , Guscetti F. , Reichler I. M. , Geissbühler U. , Braun S. A. , Arnold S.
Published: April 2008

A focal uterine adenomyosis is described in two bitches. In both cases, the uterus showed knobbly enlargements of 4 to 8 cm in diameter, which resulted in distinct clinical symptoms. Other pathological changes of the uterus were not present. One bitch was presented because of a history of vaginal discharge of several months' duration. Radiographs, as well as ultrasonography, revealed a soft tissue lesion at the cervix. The other bitch showed a marked reduction In its general condition and a sudden onset of a tense abdomen. Radiologically, a lesion of soft tissue opacity was observed in the mid‐abdomen and was seen to originate from the left uterine horn during exploratory laparotomy. A torsion of the lesion was present, which explained the clinical signs in this second case.
Effects of feeding regimens on bodyweight, composition and condition score in cats following ovariohysterectomy
Authors: Harper E. J. , Stack D. M. , Watson T. D. G. , Moxham G.
Published: April 2008

The effects of ovariohysterectomy on bodyweight, composition and condition score were evaluated in 49 cats that were fed ad libitum and 11 cats that had their food allowances controlled with the aim of maintaining a stable bodyweight. In cats fed ad libitum, bodyweight increased by an average of 31 per cent in the 12 months following ovariohysterectomy compared with 3‐1 per cent over the 12 months before surgery, and this was largely due to increased body fat content. There was no difference in weight gain between cats fed dry or canned foods, but weight gain was inversely related to age and bodyweight at the time of neutering. Mean bodyweight increased by 7‐5 per cent in the controlled feeding group, compared with 3–6 per cent over the 12 months before surgery, and individual bodyweights were maintained to within 10 per cent of pre‐neutering values in nine cats. The other two cats experienced substantial weight gain (+20 per cent and +36 per cent), despite being fed only 40 kcal/kg/day. There were no significant changes in body composition of cats with controlled dietary allowances and their condition scores were significantly lower than those of cats fed ad libitum. The results confirm a link between ovariohysterectomy and the development of obesity in cats with free access to food, and indicate that substantial reductions in energy intake are required to prevent weight gain in such cats.
Cerebral Amyloid Angiopathy and Parenchymal Amyloid Deposition in Transgenic Mice Expressing the Danish Mutant Form of Human BRI2
Authors: Vidal Ruben , Barbeito Ana G. , Miravalle Leticia , Ghetti Bernardino
Published: April 2008

Familial Danish dementia (FDD) is an autosomal dominant neurodegenerative disease clinically characterized by the presence of cataracts, hearing impairment, cerebellar ataxia and dementia. Neuropathologically, FDD is characterized by the presence of widespread cerebral amyloid angiopathy (CAA), parenchymal amyloid deposition and neurofibrillary tangles. FDD is caused by a 10‐nucleotide duplication‐insertion in the BRI2 gene that generates a larger‐than‐normal precursor protein, of which the Danish amyloid subunit (ADan) comprises the last 34 amino acids. Here, we describe a transgenic mouse model for FDD (Tg‐FDD) in which the mouse Prnp (prion protein) promoter drives the expression of the Danish mutant form of human BRI2 . The main neuropathological findings in Tg‐FDD mice are the presence of widespread CAA and parenchymal deposition of ADan. In addition, we observe the presence of amyloid‐associated gliosis, an inflammatory response and deposition of oligomeric ADan. As the animals aged, they showed abnormal grooming behavior, an arched back, and walked with a wide‐based gait and shorter steps. This mouse model may give insights on the pathogenesis of FDD and will prove useful for the development of therapeutics. Moreover, the study of Tg‐FDD mice may offer new insights into the role of amyloid in neurodegeneration in other disorders, including Alzheimer disease.
Quantification of Naturally Occurring Pyrrole Acids in Melanosomes†
Authors: Ward Weslyn C. , Lamb Erin C. , Gooden David , Chen Xin , Burinsky David J. , Simon John D.
Published: April 2008

Three naturally occurring pyrrole acids were found in Sepia, human black hair, and bovine choroid and iris melanosomes using high‐performance liquid chromatography and mass spectrometry—pyrrole‐2,3‐dicarboxylic acid (PDCA), pyrrole‐2,3,5‐tricarboxylic acid (PTCA) and pyrrole‐2,3,4,5‐tetracarboxylic acid (PTeCA). PDCA and PTCA are common markers quantified from oxidative degradation of eumelanins. Using standards, the amounts of naturally occurring PDCA and PTCA were determined and compared to those obtained following peroxide oxidation of the same samples. Because the naturally occurring acids are water soluble, these results indicate that care must be exercised when comparing PDCA and PTCA yields from the degradation analyses of melanins isolated and prepared by different methods. This work also establishes that PTeCA is a naturally occurring pyrrole acid in melanosomes.
Transient Vibronic Structure in Ultrafast Fluorescence Spectra of Photoactive Yellow Protein†
Authors: Nakamura Ryosuke , Hamada Norio , Ichida Hideki , Tokunaga Fumio , Kanematsu Yasuo
Published: April 2008

The ultrafast photo‐induced dynamics of wild‐type photoactive yellow protein and its site‐directed mutant of E46Q in aqueous solution was studied at room temperature by femtosecond fluorescence spectroscopy using the optical Kerr‐gate method. The vibronic structure appears, depending on the excitation photon energy, in the time‐resolved fluorescence spectra just after photoexcitation, which winds with time and disappears on a time scale of sub‐picoseconds. This result indicates that the wavepacket is localized in the electronic excited state followed by dumped oscillations and broadening, and also that the initial condition of the wavepacket prepared depending on the excitation photon energy affects much the following ultrafast dynamics in the electronic excited state.
Surface Elastic Properties of Human Retinal Pigment Epithelium Melanosomes†
Authors: Guo Senli , Hong Lian , Akhremitchev Boris B. , Simon John D.
Published: April 2008

Atomic force microscope (AFM) imaging and nanoindentation measurements in water were used to probe the mechanical properties of retinal pigment epithelium melanosomes isolated from 14‐year‐old and 76‐year‐old donors. Topographic imaging reveals surface roughness similar to previous measurements on dry melanosomes. Force‐indentation measurements show different types of responses that were catalogued into four different categories. In these measurements no permanent surface damage of melanosomes was observed as revealed by imaging before and after indentation measurements. The indentation measurements that exhibited nearly elastic responses were used to determine the Young’s modulus of melanosomes. The average Young’s modulus values are similar for 14‐year‐old and 76‐year‐old melanosomes with a somewhat narrower distribution for the 14‐year‐old sample. These elastic modulus values are considerably higher than the modulus of organelles with cytoplasm (<1 MPa) and approaching values of the modulus of protein crystals (∼100 MPa) indicating rather high packing density of biologic material in melanosomes. The width of the Young’s modulus distributions is considerable spanning from few megapascals to few tens of megapascals indicating large heterogeneity in the structure. A fraction of the force curves cannot be described by the homogeneous elastic sample model; these force curves are consistent with ∼10 nm structural heterogeneity in melanosomes. The approach‐withdraw hysteresis indicates a significant viscoelasticity, particularly in the samples from the 14‐year‐old sample. Adhesion of the AFM probe was detected on ∼3% and ∼20% of the surface of 14‐year‐old and 76‐year‐old samples, respectively. In light of previous studies on these same melanosomes using photoelectron emission microscopy, this adhesion is attributed to the presence of lipofuscin on the surface of the melanosomes. This suggestion indicates that part of the difference in photochemical properties between the old and young melanosomes originates from surface lipofuscin.
Quantitation of the Effect of Hydroxylamine on Rhodopsin Palmitylation†
Authors: Jackson Wesley , Ablonczy Zsolt , Crouch Rosalie K.
Published: April 2008

Rhodopsin (the photosensitive rod visual pigment) has been a model for photobiologic studies of the opsins as well as a structural model for G‐protein‐coupled receptors. The two palmitate groups attached to cysteines 322 and 323 are thought to serve as membrane anchors for the rhodopsin C‐terminus, but the absence of the palmitates does not alter membrane localization. However, removal of the palmitates affects rhodopsin function. Therefore, it is important to quantitate the stability of rhodopsin palmitates to hydroxylamine, which is a widely utilized reagent in biochemical preparations of the apoprotein. We have developed a mass spectrometric method to quantitate the resulting opsin palmitylation. Our data show that both of the bovine rhodopsin palmitates are labile to hydroxylamine, with significant depalmitylation occurring at concentrations of ≥100 mm, with an EC50 of 220 mm L−1. The palmitate at position 322 is the more stable to hydroxylamine. Samples prepared in the presence of >50 mm should therefore be considered to be at least partially depalmitylated and the results interpreted accordingly.
Identification of Six New Photoactive Yellow Proteins—Diversity and Structure–Function Relationships in a Bacterial Blue Light Photoreceptor†
Authors: Kumauchi Masato , Hara Miwa T. , Stalcup Page , Xie Aihua , Hoff Wouter D.
Published: April 2008

Photoactive yellow proteins (PYP) are bacterial photoreceptors with a Per‐Arnt‐Sim (PAS) domain fold. We report the identification of six new PYPs, thus nearly doubling the size of this protein family. This extends the taxonomic diversity of PYP‐containing bacteria from photosynthetic to nonphotosynthetic bacteria, from aquatic to soil‐dwelling organisms, and from Proteobacteria to Salinibacter ruber from the phylum Bacteriodetes. The new PYPs greatly increase the sequence diversity of the PYP family, reducing the most prevalent pair‐wise identity from 45% to 25%. Sequence alignments and analysis indicate that all 14 PYPs share a common structure with 13 highly conserved residues that form the chromophore binding pocket. Nevertheless, the functional properties of the PYPs vary greatly—the absorbance maximum extends from 432 to 465 nm, the pKa of the chromophore varies from pH 2.8 to 10.2, and the lifetime of the presumed PYP signaling state ranges from 1 ms to 1 h. Thus, the PYP family offers an excellent opportunity to investigate how functional properties are tuned over a wide range, while maintaining the same overall protein structural fold. We discuss the implications of these results for structure–function relationships in the PYP family.
Beneficial Effect of Angiotensin II Type 1 Receptor Blocker Antihypertensive Treatment on Arterial Stiffness: The Role of Smoking
Authors: Vyssoulis Gregory P. , Karpanou Eva A. , Kyvelou Stella‐Maria G. , Adamopoulos Dionysios N. , Antonakoudis George C. , Deligeorgis Alexandros D. , Cokkinos Dennis V. , Stefanadis Christodoulos I.
Published: April 2008

The purpose of the present study was to assess angiotensin receptor blocker (ARB) treatment on arterial stiffness in select hypertensive patients and define possible differences between smokers and nonsmokers. The authors evaluated 81 consecutive, nondiabetic patients (mean age, 52 years; 47 men) with uncomplicated essential hypertension with high plasma renin activity who were administered monotherapy with irbesartan, an ARB, at maximal dose. Patients were divided into smokers (n=24) and nonsmokers (n=57). Carotid‐radial pulse wave velocity (PWVc‐r), carotid‐femoral pulse wave velocity (PWVc‐f), and augmentation index (AIx) were measured before and 6 months after ARB antihypertensive treatment. All mean values of elastic effect indices were decreased after irbesartan monotherapy (AIx, from 26.3%to 21.2% [P<.01]; PWVc‐f, from 7.7 m/s to 7.3 m/s [P<.05], and PWVc‐r, from 8.9 m/s to 8.3 m/s [P<.001]). When comparing smokers vs nonsmokers, no difference was noted in AIx and PWVc‐f change (P=not significant), while PWVc‐r change was greater in smokers compared with nonsmokers (P<.05). Chronic ARB treatment may favorably affect arterial stiffness and wave reflections in hypertensive chronic smokers with elevated plasma renin levels.
Escalating Antihypertensive Medications in End‐Stage Renal Disease Patients Does Not Improve Blood Pressure Control
Authors: Tapolyai Mihály , Karim Jariatul , Fakhruddin Atif
Published: April 2008

The authors examined the efficacy of antihypertensive medication use in end‐stage renal disease (ESRD). They compared achieved blood pressures (BPs) in a cross‐sectional study of 106 ESRD patients whose medications had not been changed for at least 2 months. Group 1 (n=36) included patients who took 0 or 1 medication; group 2 (n=56), 2 or 3 medications; and group 3 (n=14), ≥4 medications. The population's mean age was 55.1 years, 87% were African American, and 57% were men weighing 76.9 kg who were on 229 minutes of hemodialysis with an edKt/V of 1.35; there was no difference between the 3 groups. The authors found a difference in the mean BPs: 139/72 mm Hg in group 1, 154/82 mm Hg in group 2, and 165/91 mm Hg in group 3 (P=.01 for systolic, P=.002 for diastolic), with a mean arterial pressure difference of 94.4, 106.4, and 115.4 mm Hg (P=.002). The authors conclude that in this group of primarily African American patients, the control of hypertension in ESRD is not achieved by escalating the number of antihypertensive medications.

J Clin Hypertens (Greenwich). 2008;10:215–218.
Correlating Equations for Laminar Free Convection From Misaligned Horizontal Cylinders in Interacting Flow Fields
Authors: Corcione Massimo , Cianfrini Claudio , Habib Emanuele , Moncada Lo Giudice Gino
Published: April 2008

Steady laminar free convection in air from a pair of misaligned, parallel horizontal cylinders, i.e., a pair of parallel cylinders with their axes set in a plane inclined with respect to the gravity vector, is studied numerically. A specifically developed computer code based on the SIMPLE-C algorithm is used for the solution of the dimensionless mass, momentum, and energy transfer governing equations. Results are presented for different values of the center-to-center cylinder spacing from 1.4 up to 10 diameters, the tilting angle of the two-cylinder array from 0degto90deg, and the Rayleigh number based on the cylinder diameter in the range between 103 and 107. It is found that the heat transfer rates at both cylinder surfaces may in principle be traced back to the combined contributions of the so-called plume effect and chimney effect, which are the mutual interactions occurring in the vertical and horizontal alignments, respectively. In addition, at any misalignment angle, an optimum spacing between the cylinders for the maximum heat transfer rate, which decreases with increasing the Rayleigh number, does exist. Heat transfer dimensionless correlating equations are proposed for any individual cylinder and for the pair of cylinders as a whole.
Electric Motorboat Drag Racing: A hands-on physics project that motivates students from start to finish
Authors: Barry Reno
Published: April 2008

Electric Motorboat Drag Racing is a culminating high school physics project designed to apply and bring to life many content standards for physics. Students need to be given several weeks at home to design and build their model-sized electric motorboats for the 5-meter drag racing competition down rain gutters. In the process, they are discussing and applying physics concepts from the entire course, including topics from motion, forces, energy, and electricity and magnetism. Bottom line: students of all skill levels are racing to apply physics and loving it.
Energy and the Confused Student V: The Energy/Momentum Approach to Problems Involving Rotating and Deformable Systems
Authors: Jewett John W.
Published: April 2008

Energy is a critical concept in physics problem-solving, but is often a major source of confusion for students if the presentation is not carefully crafted by the instructor or the textbook. A common approach to problems involving deformable or rotating systems that has been discussed in the literature is to employ the work-kinetic energy theorem together with a “pseudowork-kinetic energy theorem” or a “center-of-mass equation.” This article discusses an alternative approach that employs neither of these equations and allows students a more global and less confusing approach to such problems. The approach is demonstrated for three sample situations from the literature.
The Bicyclist's Paradox
Authors: Knight Randy
Published: April 2008

It's a situation every avid cyclist knows only too well. If you cycle up a hill and then back down with no net change in elevation, it seems as if your slower uphill speed and faster downhill speed should offset each other. But they don't. Your average speed is less than it would have been had you cycled the same distance on a level road. Similarly, cycling into a headwind for half your trip and returning home with a tailwind yields an average speed less than you would have achieved on a windless day. The faster part of the ride doesn't compensate for the slower part. It seems unjust. Most cyclists expect the uphill and downhill, or the headwind and tailwind, to more or less cancel and are surprised (and frustrated!) when they don't. The purpose of this paper is to resolve this paradox. Doing so involves some nice real-world applications of Newton's laws, numerical problem solving, and exercise physiology. There's a lot to learn from analyzing this problem, and it's readily accessible to introductory physics students.
Newton in the Big Apple: Access to High School Physics in New York City
Authors: Kelly Angela M. , Sheppard Keith
Published: April 2008

Despite reports to the contrary,1 the availability of physics as a course for high school students is not equitably distributed throughout the United States. While some schools provide physics for all who wish to take it, a more common scenario is limited availability, often open only to the few students who have completed the necessary prerequisite courses. This is particularly true in urban districts where physics is not universally available in secondary school.
Understanding the Fine Tuning in Our Universe
Authors: Cohen Bernard L.
Published: April 2008

I It is often stated that the physical properties of our universe are “fine tuned”—that is, they must be almost exactly as they are to make the development of intelligent life possible.1 The implications of this statement, called the “anthropic principle,” have been widely discussed in a philosophical context,2 but the scientific basis for the statement3 is not widely understood outside the community of experts. My purpose here is to explain how I have presented some parts of this scientific basis, albeit with some glossing over of difficult and/or less important details, to undergraduate students majoring in humanities and social sciences and to senior citizens in “lifetime learning” programs who have no professional scientific background. In this paper, I concentrate on the vital processes of hydrogen burning and helium burning.
Magnetic Low-Friction Track
Authors: Paetkau Mark , Bahniwal Manpreet , Gamblen James
Published: April 2008

The standard low-friction tracks used to test Newton's laws are the air track and the low-friction cart track. Both are commercially available and provide low-friction environments to test various physics concepts. At a recent science fair, one of the authors (JG) presented a magnetically levitated cart and track. A literature search found no previous testing of magnetically levitated carts.1 This paper compares a magnetically levitated cart against the two standard low-friction tracks.
Determining Chondritic Impactor Size from the Marine Osmium Isotope Record
Authors: Paquay François S. , Ravizza Gregory E. , Dalai Tarun K. , Peucker-Ehrenbrink Bernhard
Published: April 2008

Decreases in the seawater
187
Os/
188
Os ratio caused by the impact of a chondritic meteorite are indicative of projectile size, if the soluble fraction of osmium carried by the impacting body is known. Resulting diameter estimates of the Late Eocene and Cretaceous/Paleogene projectiles are within 50% of independent estimates derived from iridium data, assuming total vaporization and dissolution of osmium in seawater. The variations of
187
Os/
188
Os and Os/Ir across the Late Eocene impact-event horizon support the main assumptions required to estimate the projectile diameter. Chondritic impacts as small as 2 kilometers in diameter should produce observable excursions in the marine osmium isotope record, suggesting that previously unrecognized impact events can be identified by this method.
Evidence for Editing of Human Papillomavirus DNA by APOBEC3 in Benign and Precancerous Lesions
Authors: Vartanian Jean-Pierre , Guétard Denise , Henry Michel , Wain-Hobson Simon
Published: April 2008

Cytidine deaminases of the APOBEC3 family all have specificity for single-stranded DNA, which may become exposed during replication or transcription of double-stranded DNA. Three human APOBEC3A (
hA3A
),
hA3B
, and
hA3H
genes are expressed in keratinocytes and skin, leading us to determine whether genetic editing of human papillomavirus (HPV) DNA occurred. In a study of HPV1a plantar warts and HPV16 precancerous cervical biopsies, hyperedited HPV1a and HPV16 genomes were found. Strictly analogous results were obtained from transfection experiments with HPV plasmid DNA and the three nuclear localized enzymes: hA3A, hA3C, and hA3H. Thus, stochastic or transient overexpression of
APOBEC3
genes may expose the genome to a broad spectrum of mutations that could influence the development of tumors.
Amplification of Cretaceous Warmth by Biological Cloud Feedbacks
Authors: Kump Lee R. , Pollard David
Published: April 2008

The extreme warmth of particular intervals of geologic history cannot be simulated with climate models, which are constrained by the geologic proxy record to relatively modest increases in atmospheric carbon dioxide levels. Recent recognition that biological productivity controls the abundance of cloud condensation nuclei (CCN) in the unpolluted atmosphere provides a solution to this problem. Our climate simulations show that reduced biological productivity (low CCN abundance) provides a substantial amplification of CO
2
-induced warming by reducing cloud lifetimes and reflectivity. If the stress of elevated temperatures did indeed suppress marine and terrestrial ecosystems during these times, this long-standing climate enigma may be solved.
Deconstruction of Iterative Multidomain Polyketide Synthase Function
Authors: Crawford Jason M. , Thomas Paul M. , Scheerer Jonathan R. , Vagstad Anna L. , Kelleher Neil L. , Townsend Craig A.
Published: April 2008

PksA, which initiates biosynthesis of the environmental carcinogen aflatoxin B1, is one of the multidomain iterative polyketide synthases (IPKSs), a large, poorly understood family of biosynthetic enzymes. We found that dissection of PksA and its reconstitution from selected sets of domains allows the accumulation and characterization of advanced octaketide intermediates bound to the enzyme, permitting the reactions controlled by individual catalytic domains to be identified. A product template (PT) domain unites with the ketosynthase and thioesterase in this IPKS system to assemble precisely seven malonyl-derived building blocks to a hexanoyl starter unit and mediate a specific cyclization cascade. Because the PT domain is common among nonreducing IPKSs, these mechanistic features should prove to be general for IPKS-catalyzed production of aromatic polyketides.
Aligning Conservation Priorities Across Taxa in Madagascar with High-Resolution Planning Tools
Authors: Kremen C. , Cameron A. , Moilanen A. , Phillips S. J. , Thomas C. D. , Beentje H. , Dransfield J. , Fisher B. L. , Glaw F. , Good T. C. , Harper G. J. , Hijmans R. J. , Lees D. C. , Louis E. , Nussbaum R. A. , Raxworthy C. J. , Razafimpahanana A. , Schatz G. E. , Vences M. , Vieites D. R. , Wright P. C. , Zjhra M. L.
Published: April 2008

Globally, priority areas for biodiversity are relatively well known, yet few detailed plans exist to direct conservation action within them, despite urgent need. Madagascar, like other globally recognized biodiversity hot spots, has complex spatial patterns of endemism that differ among taxonomic groups, creating challenges for the selection of within-country priorities. We show, in an analysis of wide taxonomic and geographic breadth and high spatial resolution, that multitaxonomic rather than single-taxon approaches are critical for identifying areas likely to promote the persistence of most species. Our conservation prioritization, facilitated by newly available techniques, identifies optimal expansion sites for the Madagascar government's current goal of tripling the land area under protection. Our findings further suggest that high-resolution multitaxonomic approaches to prioritization may be necessary to ensure protection for biodiversity in other global hot spots.
Effects of Antenatal and Postnatal Environments on CD4 T-Cell Responses toMycobacterium bovisBCG in Healthy Infants in The Gambia
Authors: Miles David J. C. , van der Sande Marianne , Crozier Sarah , Ojuola Olubukola , Palmero Melba S. , Sanneh Mariama , Touray Ebrima S. , Rowland-Jones Sarah , Whittle Hilton , Ota Martin , Marchant Arnaud
Published: April 2008

TheMycobacterium bovisBCG vaccine has a poor record of efficacy in low-income tropical settings. Against this background, we evaluated the immune response of infants to mycobacterial antigens over the 2 years following BCG vaccination at birth by measuring the gamma interferon (IFN-γ), interleukin-2 (IL-2), and CD154 responses of CD4 T cells. Similar numbers of cells expressed IFN-γ in infants, 4- to 5-year-old children, and adults, while CD154 was not expressed at comparable levels until the second year of infancy. The IL-2 response remained relatively low in infants, children, and adults but correlated negatively with mother's body mass index and was highest among infants born to Mandinka mothers. Similarly, infants born in the wet season had a stronger CD154 response than those born in the dry season throughout the 2 years of the study. We conclude that the prenatal and perinatal environments have a lasting effect on the response of infants to the BCG vaccine.
Association of Mannose-Binding Lectin Gene Polymorphism but Not of Mannose-Binding Serine Protease 2 with Chronic Severe Aortic Regurgitation of Rheumatic Etiology
Authors: Ramasawmy Rajendranath , Spina Guilherme S. , Fae Kellen C. , Pereira Alexandre C. , Nisihara Renato , Messias Reason Iara Jose , Grinberg Max , Tarasoutchi Flavio , Kalil Jorge , Guilherme Luiza
Published: April 2008

N-Acetylglucosamine (GlcNAc) is the major immunoepitope of group A streptococcal cell wall carbohydrates. Antistreptococcal antibodies cross-reactive with anti-GlcNAc and laminin are present in sera of patients with rheumatic fever. The cross-reactivity of these antibodies with human heart valvular endothelium and the underlying basement membrane has been suggested to be a possible cause of immune-mediated valve lesion. Mannose-binding lectin (MBL) encoded by theMBL2gene, a soluble pathogen recognition receptor, has high affinity for GlcNAc. We postulated that mutations in exon 1 of theMBL2 gene associated with a deficient serum level of MBL may contribute to chronic severe aortic regurgitation (AR) of rheumatic etiology. We studied 90 patients with severe chronic AR of rheumatic etiology and 281 healthy controls (HC) for the variants of theMBL2gene at codons 52, 54, and 57 by using a PCR-restriction fragment length polymorphism-based method. We observed a significant difference in the prevalence of defectiveMBL2alleles between patients with chronic severe AR and HC. Sixteen percent of patients with chronic severe AR were homozygotes or compound heterozygotes for defective MBL alleles in contrast to 5% for HC (P= 0.0022; odds ratio, 3.5 [95% confidence interval, 1.6 to 7.7]). No association was detected with the variant of theMASP2gene. Our study suggests that MBL deficiency may contribute to the development of chronic severe AR of rheumatic etiology.
Caspofungin Disk Diffusion Breakpoints and Quality Control
Authors: Brown Steven D. , Traczewski Maria M.
Published: April 2008

Interpretive disk diffusion breakpoints for caspofungin are proposed by evaluating 762 isolates of
Candida
spp., representing 10 different species obtained as part of the caspofungin clinical trials. Standardized broth microdilution reference tests were compared to the zone diameters observed with 5-μg caspofungin disks produced by two different disk manufacturers. Disk diffusion breakpoints of ≥11 mm for susceptible are proposed. Compared to results from MIC testing, these zone diameters produced error rates that were ≤0.3% for all categories. In addition, an eight-laboratory disk diffusion quality control (QC) study was performed, and QC ranges are proposed for the four QC strains recommended by the CLSI.
The LEM Domain Proteins Emerin and LAP2α Are Dispensable for Human Immunodeficiency Virus Type 1 and Murine Leukemia Virus Infections
Authors: Mulky Alok , Cohen Tatiana V. , Kozlov Serguei V. , Korbei Barbara , Foisner Roland , Stewart Colin L. , KewalRamani Vineet N.
Published: April 2008

The human nuclear envelope proteins emerin and lamina-associated polypeptide 2α (LAP2α) have been proposed to aid in the early replication steps of human immunodeficiency virus type 1 (HIV-1) and murine leukemia virus (MLV). However, whether these factors are essential for HIV-1 or MLV infection has been questioned. Prior studies in which conflicting results were obtained were highly dependent on RNA interference-mediated gene silencing. To shed light on these contradictory results, we examined whether HIV-1 or MLV could infect primary cells from mice deficient for emerin, LAP2α, or both emerin and LAP2α. We observed HIV-1 and MLV infectivity in mouse embryonic fibroblasts (MEFs) from emerin knockout, LAP2α knockout, or emerin and LAP2α double knockout mice to be comparable in infectivity to wild-type littermate-derived MEFs, indicating that both emerin and LAP2α were dispensable for HIV-1 and MLV infection of dividing, primary mouse cells. Because emerin has been suggested to be important for infection of human macrophages by HIV-1, we also examined HIV-1 transduction of macrophages from wild-type mice or knockout mice, but again we did not observe a difference in susceptibility. These findings prompted us to reexamine the role of human emerin in supporting HIV-1 and MLV infection. Notably, both viruses efficiently infected human cells expressing high levels of dominant-negative emerin. We thus conclude that emerin and LAP2α are not required for the early replication of HIV-1 and MLV in mouse or human cells.
Mutagenesis of the Active-Site Cysteine in the Ubiquitin-Specific Protease Contained in Large Tegument Protein pUL36 of Pseudorabies Virus Impairs Viral Replication In Vitro and Neuroinvasion In Vivo
Authors: Böttcher Sindy , Maresch Christina , Granzow Harald , Klupp Barbara G. , Teifke Jens P. , Mettenleiter Thomas C.
Published: April 2008

Herpesviruses specify a ubiquitin-specific protease activity located within their largest tegument protein. Although its biological role is still largely unclear, mutation within the active site abolished deubiquitinating (DUB) activity and decreased virus replication in vitro and in vivo. To further elucidate the role of DUB activity for herpesvirus replication, the conserved active-site cysteine at amino acid position 26 within pUL36 of
Pseudorabies virus
(PrV) (
Suid herpesvirus 1
), a neurotropic alphaherpesvirus, was mutated to serine. Whereas one-step growth kinetics of the resulting mutant virus PrV-UL36(C
26
S) were moderately reduced, plaque size was decreased to 62% of that of the wild-type virus. Ultrastructural analysis revealed large accumulations of unenveloped nucleocapsids in the cytoplasm, but incorporation of the tegument protein pUL37 was not abolished. After intranasal infection with PrV-UL36(C
26
S) mice showed survival times two times longer than those of mice infected with wild-type or rescued virus. Thus, the DUB activity is important for PrV replication in vitro and for neuroinvasion in mice.
Enhanced Pathogenesis of an Attenuated Herpes Simplex Virus for Mice Lacking Stat1
Authors: Pasieka Tracy Jo , Lu Betty , Leib David A.
Published: April 2008

Mice lacking the Stat1 interferon signaling gene were infected with herpes simplex virus type 1 (HSV-1) or an attenuated recombinant lacking virion host shutoff (Δ
vhs
). Δ
vhs
virus
-
infected Stat1
−/−
mice showed levels of replication equivalent to that of the wild-type virus-infected control mice but reduced relative to wild-type virus-infected Stat1
−/−
mice. Stat1 deficiency relieves the immunomodulatory deficiency of Δ
vhs
virus, but not its inherent growth defect. Also Vhs is dispensable for reactivation.
Systematic Study of the Functions for the Residues around the Nucleotide Pocket in Simian Virus 40 AAA+ Hexameric Helicase
Authors: Greenleaf William B. , Shen Jingping , Gai Dahai , Chen Xiaojiang S.
Published: April 2008

The high-resolution structural data for simian virus 40 large-T-antigen helicase revealed a set of nine residues bound to ATP/ADP directly or indirectly. The functional role of each of these residues in ATP hydrolysis and also the helicase function of this AAA+ (
A
TPases
a
ssociated with various cellular
a
ctivities) molecular motor are unclear. Here, we report our mutational analysis of each of these residues to examine their functionality in oligomerization, DNA binding, ATP hydrolysis, and double-stranded DNA (dsDNA) unwinding. All mutants were capable of oligomerization in the presence of ATP and could bind single-stranded DNA and dsDNA. ATP hydrolysis was substantially reduced for proteins with mutations of residues making direct contact with the γ-phosphate of ATP or the apical water molecule. A potentially noncanonical “arginine finger” residue, K418, is critical for ATP hydrolysis and helicase function, suggesting a new type of arginine finger role by a lysine in the stabilization of the transition state during ATP hydrolysis. Interestingly, our mutational data suggest that the positive- and negative-charge interactions in the uniquely observed residue pairs, R498/D499 and R540/D502, in large-T-antigen helicase are critically involved in the transfer of energy of ATP binding/hydrolysis to DNA unwinding.
Site 1 Protease Is Required for Proteolytic Processing of the Glycoproteins of the South American Hemorrhagic Fever Viruses Junin, Machupo, and Guanarito
Authors: Rojek Jillian M. , Lee Andrew M. , Nguyen NgocThao , Spiropoulou Christina F. , Kunz Stefan
Published: April 2008

The cellular proprotein convertase
s
ite
1 p
rotease (S1P) has been implicated in the proteolytic processing of the glycoproteins (GPs) of Old World arenaviruses. Here we report that S1P is also involved in the processing of the GPs of the genetically more-distant South American hemorrhagic fever viruses Guanarito, Machupo, and Junin. Efficient cleavage of Guanarito virus GP, whose protease recognition sites deviate from the reported S1P consensus sequence, indicates a broader specificity of S1P than anticipated. Lack of GP processing of Junin virus dramatically reduced production of infectious virus and prevented cell-to-cell propagation. Infection of S1P-deficient cells resulted in viral persistence over several weeks without the emergence of escape variants able to use other cellular proteases for GP processing.
A Subgenomic Segment of Theiler's Murine Encephalomyelitis Virus RNA Causes Demyelination
Authors: Baida Gleb , Popko Brian , Wollmann Robert L. , Stavrou Spyridon , Lin Wensheng , Tretiakova Maria , Krausz Thomas N. , Roos Raymond P.
Published: April 2008

The DA strain of Theiler's murine encephalomyelitis virus (TMEV) causes a persistent central nervous system (CNS) infection of mice with a restricted virus gene expression and induces an inflammatory demyelinating disease that is thought to be immune mediated and a model of multiple sclerosis (MS). The relative contribution of virus vis-à-vis the immune system in the pathogenesis of DA-induced white matter disease remains unclear, as is also true in MS. To clarify the pathogenesis of DA-induced demyelination, we used Cre/loxP technology to generate a transgenic mouse that has tamoxifen (Tm)-inducible expression of a subgenomic segment of DA RNA in oligodendrocytes and Schwann cells. Tm-treated young transgenic mice developed progressive weakness leading to death, with abnormalities of oligodendrocytes and Schwann cells and demyelination, but without inflammation, demonstrating that DA virus can play a direct pathogenic role in demyelination. Tm treatment of mice at a later age resulted in milder disease, with evidence of peripheral nerve remyelination and focal fur depigmentation; surviving weak mice had persistent expression of the recombined transgene in the CNS, suggesting that the DA subgenomic segment can cause cellular dysfunction but not death, possibly similar to the situation seen during DA virus persistence. These studies demonstrate that DA RNA or a DA protein(s) is toxic to myelin-synthesizing cells. This Cre/loxP transgenic system allows for spatially and temporally controlled expression of the viral transgene and is valuable for clarifying nonimmune (and immune) mechanisms of demyelination induced by TMEV as well as other viruses.
Small Intestine CD4
+
T Cells Are Profoundly Depleted during Acute Simian-Human Immunodeficiency Virus Infection, Regardless of Viral Pathogenicity
Authors: Fukazawa Yoshinori , Miyake Ariko , Ibuki Kentaro , Inaba Katsuhisa , Saito Naoki , Motohara Makiko , Horiuchi Reii , Himeno Ai , Matsuda Kenta , Matsuyama Megumi , Takahashi Hidemi , Hayami Masanori , Igarashi Tatsuhiko , Miura Tomoyuki
Published: April 2008

To analyze the relationship between acute virus-induced injury and the subsequent disease phenotype, we compared the virus replication and CD4
+
T-cell profiles for monkeys infected with isogenic highly pathogenic (KS661) and moderately pathogenic (#64) simian-human immunodeficiency viruses (SHIVs). Intrarectal infusion of SHIV-KS661 resulted in rapid, systemic, and massive virus replication, while SHIV-#64 replicated more slowly and reached lower titers. Whereas KS661 systemically depleted CD4
+
T cells, #64 caused significant CD4
+
T-cell depletion only in the small intestine. We conclude that SHIV, regardless of pathogenicity, can cause injury to the small intestine and leads to CD4
+
T-cell depletion in infected animals during acute infection.
Topology of Potential Phase Diagrams of Partially Open Condensed System
Authors: Voňka Petr , Leitner Jindřich , Sedmidubský David
Published: April 2008

An analysis of topology of two-dimensional isothermal potential phase diagrams of partially open immiscible condensed systems is presented. The systems share two independent components with surroundings. Chemical potentials (or derived properties such as activities or relative partial pressures) of these two independent components are used as coordinates of such diagrams. Several theorems on topology having practical consequences are proved.
Analysis of masonry structures: review of and recent trends in homogenization techniquesThis article is one of a selection of papers published in this Special Issue on Masonry.
Authors: Lourenço Paulo B. , Milani Gabriele , Tralli Antonio , Zucchini Alberto
Published: April 2008

The mechanics of masonry structures have been underdeveloped for a long time in comparison with other fields of knowledge. Presently, nonlinear analysis is a popular field in masonry research and homogenization techniques play a major role despite the mathematical and conceptual difficulties inherent to this approach. This paper addresses different homogenization techniques available in published literature, aiming at defining a first catalogue and at discussing the advantages and disadvantages of the different approaches. Finally, special attention is given to a micromechanical based model and a model based on a polynomial expansion of the microstress field. These seem promising and accurate strategies for advanced structural analysis.
Influence of age on masonry bond strength and mortar microstructureThis article is one of a selection of papers published in this Special Issue on Masonry.
Authors: Sugo Heber , Page Adrian W. , Lawrence Stephen
Published: April 2008

The effect of age on bond strength and mortar microstructure was investigated as part of an ongoing masonry bond strength research program at The University of Newcastle. Previous work has shown that both strength losses and strength gains occur with age. The potential loss of bond strength with time has structural implications as the design of masonry using the Australian masonry standard AS 3700–2001 is based on the 7 d bond strength. In this investigation, a single mortar-and-unit combination (dry pressed clay and 1:1:6 mortar) cured under ambient laboratory conditions was studied. Bond strength was determined at ages ranging from 3 to 365 d using a small-scale uniaxial tension test. Maximum bond strength was observed to occur at 180 d with strength minima occurring at 90 and 365 d. Scanning electron microscopy and X-ray diffraction techniques were used to further identify the mortar constituents and hydration levels. Changes in the density of the paste microstructure were observed up to 28 d, which correlated with the initial increase in bond strength. No other microstructural change to account for the strength variations between 28 and 365 d could be observed using these techniques.