The interacting roles of climate, soils, and plant production on soil microbial communities at a continental scale.

Soil microbial communities control critical ecosystem processes such as decomposition, nutrient cycling, and soil organic matter formation. Continental scale patterns in the composition and functioning of microbial communities are related to climatic, biotic, and edaphic factors such as temperature and precipitation, plant community composition, and soil carbon, nitrogen, and pH. Although these relationships have been well explored individually, the examination of the factors that may act directly on microbial communities vs. those that may act indirectly through other ecosystem properties has not been well developed. To further such understanding, we utilized structural equation modeling (SEM) to evaluate a set of hypotheses about the direct and indirect effects of climatic, biotic, and edaphic variables on microbial communities across the continental United States. The primary goals of this work were to test our current understanding of the interactions among climate, soils, and plants in affecting microbial community composition, and to examine whether variation in the composition of the microbial community affects potential rates of soil enzymatic activities. A model of interacting factors created through SEM shows several expected patterns. Distal factors such as climate had indirect effects on microbial communities by influencing plant productivity, soil mineralogy, and soil pH, but factors related to soil organic matter chemistry had the most direct influence on community composition. We observed that both plant productivity and soil mineral composition were important indirect influences on community composition at the continental scale, both interacting to affect organic matter content and microbial biomass and ultimately community composition. Although soil hydrolytic enzymes were related to the moisture regime and soil carbon, oxidative enzymes were also affected by community composition, reflected in the abundance of soil fungi. These results highlight that soil microbial communities can be modeled within the context of multiple interacting ecosystem properties acting both directly and indirectly on their composition and function, and this provides a rich and informative context with which to examine communities. This work also highlights that variation in climate, microbial biomass, and microbial community composition can affect maximum rates of soil enzyme activities, potentially influencing rates of decomposition and nutrient mineralization in soils.

Electromyographic Responses from the Vastus Medialis during Isometric Muscle Actions.

This study examined the electromyographic (EMG) responses from the vastus medialis (VM) for electrodes placed over and away from the innervation zone (IZ) during a maximal voluntary isometric contraction (MVIC) and sustained, submaximal isometric muscle action. A linear electrode array was placed on the VM to identify the IZ and muscle fiber pennation angle during an MVIC and sustained isometric muscle action at 50% MVIC. EMG amplitude and frequency parameters were determined from 7 bipolar channels of the electrode array, including over the IZ, as well as 10 mm, 20 mm and 30 mm proximal and distal to the IZ. There were no differences between the channels for the patterns of responses for EMG amplitude or mean power frequency during the sustained, submaximal isometric muscle action; however, there were differences between channels during the MVIC. The results of the present study supported the need to standardize the placement of electrodes on the VM for the assessment of EMG amplitude and mean power frequency. Based on the current findings, it is recommended that electrode placements be distal to the IZ and aligned with the muscle fiber pennation angle during MVICs, as well as sustained, submaximal isometric muscle actions.

Infrared microcalorimetric spectroscopy using quantum cascade lasers.

We have investigated an IR microcalorimetric spectroscopy technique that can be used to detect the presence of trace amounts of target molecules. The chemical detection is accomplished by obtaining the IR photothermal spectra of molecules adsorbed on the surface of uncooled thermal micromechanical detectors. Although we use a chemical layer to absorb target molecules, IR microcalorimetric spectroscopy requires no chemical specific coatings. The chemical specificity of the presented method is a consequence of the wavelength-specific absorption of IR photons from tunable quantum cascade lasers due to vibrational spectral bands of the analyte. We have obtained IR photothermal spectra for trace concentrations of 1,3,5-Trinitroperhydro-1,3,5-triazine and a monolayer of 2-Sulfanylethan-1-ol (2-mercaptoethanol) over the wavelength region from 6 to 10 µm. We found that both chemicals exhibit a number of photothermal absorption features that are in good agreement with their respective IR spectra.

Effects of neuromuscular fatigue on the electromechanical delay of the leg extensors and flexors in young and old men.

PURPOSE: The purpose of this study was to investigate the effects of a fatigue-inducing bout of submaximal, intermittent isometric contractions on the electromechanical delay (EMD) of the leg extensors and flexors in young and old men. METHODS: Twenty young (mean ± SD: age = 25 ± 2.8 years) and sixteen old (age = 70.8 ± 3.8) recreationally active men performed maximal voluntary contractions (MVCs) followed by a fatigue-inducing protocol consisting of intermittent isometric contractions of the leg extensors or flexors using a 0.6 duty cycle (6 s contraction, 4 s relaxation) at 60 % of MVC until volitional fatigue. MVCs were again performed at 0, 7, 15, and 30 min post fatigue. A three-way mixed factorial ANOVA was used to analyze the EMD data. RESULTS: There was a two-way muscle × time interaction (P = 0.039) where the EMD of the leg flexors was greater (P = 0.001-0.034) compared with baseline at all post fatigue time periods, but was only greater at immediately post fatigue for the extensors (P = 0.001). A significant two-way interaction for muscle × age (P = 0.009) revealed that the EMD was greater (P = 0.003) for the extensors for the old compared with the young men, but not different for the flexors (P = 0.506). CONCLUSIONS: These findings showed differential fatigue-induced EMD recovery patterns between the leg extensors and flexors with the flexors being slower to recover and also that age-related increases of EMD are muscle group specific. The sustained increased EMD of the flexors during recovery may have important injury and performance implications in a variety of populations and settings.

Mice lacking the myotonic dystrophy protein kinase develop a late onset progressive myopathy.

Myotonic dystrophy (DM) is an autosomal dominant disorder resulting from the expansion of a CTG repeat in the 3' untranslated region of a putative protein kinase (DMPK). To elucidate the role of DMPK in DM pathogenesis we have developed Dmpk deficient (Dmpk-/-) mice. Dmpk-/-mice develop a late-onset, progressive skeletal myopathy that shares some pathological features with DM. Muscles from mature mice show variation in fibre size, increased fibre degeneration and fibrosis. Adult Dmpk-/-mice show ultrastructural changes in muscle and a 50% decrease in force generation compared to young mice. Our results indicate that DMPK may be necessary for the maintenance of skeletal muscle structure and function and suggest that a decrease in DMPK levels may contribute to DM pathology.

Relative risk of acute pancreatitis in initiators of exenatide twice daily compared with other anti-diabetic medication: a follow-up study.

AIMS: Previously, a retrospective cohort study found no increased risk of acute pancreatitis with current or recent use of exenatide twice daily compared with use of other anti-diabetic drugs. This follow-up study investigated incident acute pancreatitis, with the use of a different data source and analytic method, in patients exposed to exenatide twice daily compared with patients exposed to other anti-diabetic medications. METHODS: A large US health insurance claims database was used. Eligible patients had ≥ 9 months continuous enrollment without a claim for pancreatitis and a claim for a new anti-diabetic medication on or after 1 June 2005 to 31 March 2009. Cases of acute pancreatitis were defined as hospitalized patients with an Internation Classification of Disease 9 code of 577.0 in the primary position. A discrete time survival model was used to evaluate the relationship between exenatide twice daily and acute pancreatitis. RESULTS: Of 482,034 eligible patients, 24,237 initiated exenatide twice daily and 457,797 initiated another anti-diabetic medication. Initiators of exenatide twice daily had more severe diabetes compared with initiators of other anti-diabetic medications. After adjustments for propensity score, insulin and use of medication potentially associated with acute pancreatitis, the odds ratio with exenatide twice daily exposure was 0.95 (95% CI 0.65-1.38). A secondary analysis that examined current, recent and past medication exposure found no increased risk of acute pancreatitis with exenatide twice daily, regardless of exposure category. CONCLUSION: This study indicates that exposure to exenatide twice daily was not associated with an increased risk of acute pancreatitis compared with exposure to other anti-diabetic medications. These results should be interpreted in light of potential residual confounding and unknown biases.

Characterization of hydrogen responsive nanoporous palladium films synthesized via a spontaneous galvanic displacement reaction.

A model is presented regarding the mechanistic properties associated with the interaction of hydrogen with nanoporous palladium (np-Pd) films prepared using a spontaneous galvanic displacement reaction (SGDR), which involves PdCl(2) reduction by atomic Ag. Characterization of these films shows both chemical and morphological factors, which influence the performance characteristics of np-Pd microcantilever (MC) nanomechanical sensing devices. Raman spectroscopy, uniquely complemented with MC response profiles, is used to explore the chemical influence of palladium oxide (PdO). These combined techniques support a reaction mechanism that provides for rapid response to H(2) and recovery in the presence of O(2). Post-SGDR processing via reduction of PdCl(2)(s) in a H(2) environment results in a segregated nanoparticle three-dimensional matrix dispersed in a silver layer. The porous nature of the reduced material is shown by high resolution scanning electron microscopy. Extended grain boundaries, typical of these materials, result in a greater surface area conducive to fast sorption/desorption of hydrogen, encouraged by the presence of PdO. X-ray diffraction and inductively coupled plasma-optical emission spectroscopy are employed to study changes in morphology and chemistry occurring in these nanoporous films under different processing conditions. The unique nature of chemical/morphological effects, as demonstrated by the above characterization methods, provides evidence in support of observed nanomechanical response/recovery profiles offering insight for catalysis, H(2) storage and improved sensing applications.

Influence of acute eccentric exercise on the H:Q ratio.

The purpose of the present study was to examine the effects of an acute bout of eccentric exercise on maximal isokinetic concentric peak torque (PT) of the leg flexors and extensors and the hamstrings-to-quadriceps (H:Q) strength ratio. Sixteen male (mean±SD: age=20.9±2 years; stature=177.0±4.4 cm; mass=76.8±10.0 kg) volunteers performed maximal, concentric isokinetic leg extension and flexion muscle actions at 60°·sec - 1 before and after (24-72 h) a bout of eccentric exercise. The eccentric exercise protocol consisted of 4 sets of 10 repetitions for the leg press, leg extension, and leg curl exercises at 120% of the concentric one repetition maximum (1-RM). The results indicated that the acute eccentric exercise protocol resulted in a significant (P<0.05) decrease in isokinetic leg flexion (13-19%) and leg extension (11-16%) PT 24-72 h post-exercise. However, the H:Q ratios were unaltered by the eccentric exercise protocol. These findings suggest that an acute bout of eccentric exercise utilizing both multi - and single - joint dynamic constant external resistance (DCER) exercises results in similar decreases in maximal isokinetic strength of the leg flexors and extensors, but does not alter the H:Q ratio.

Auditory trace fear conditioning requires perirhinal cortex.

The hippocampus is well-known to be critical for trace fear conditioning, but nothing is known about the importance of perirhinal cortex (PR), which has reciprocal connections with hippocampus. PR damage severely impairs delay fear conditioning to ultrasonic vocalizations (USVs) and discontinuous tones (pips), but has no effect on delay conditioning to continuous tones. Here we demonstrate that trace auditory fear conditioning also critically depends on PR function. The trace interval between the CS offset and the US onset was 16s. Pre-training neurotoxic lesions were produced through multiple injections of N-methyl-D-aspartate along the full length of PR, which was directly visualized during the injections. Control animals received injections with phosphate-buffered saline. Three-dimensional reconstructions of the lesion volumes demonstrated that the neurotoxic damage was well-localized to PR and included most of its anterior-posterior extent. Automated video analysis quantified freezing behavior, which served as the conditional response. PR-damaged rats were profoundly impaired in trace conditioning to either of three different CSs (a USV, tone pips, and a continuous tone) as well as conditioning to the training context. Within both the lesion and control groups, the type of cue had no effect on the mean CR. The overall PR lesion effect size was 2.7 for cue conditioning and 3.9 for context conditioning. We suggest that the role of PR in trace fear conditioning may be distinct from some of its more perceptual functions. The results further define the essential circuitry underlying trace fear conditioning to auditory cues.

Fear conditioning to discontinuous auditory cues requires perirhinal cortical function.

Pretraining lesions of rat perirhinal (PR) cortex impair fear conditioning to ultrasonic vocalizations (USVs) but have no effect on conditioning to continuous tones. This study attempted to deconstruct USVs into simpler stimulus features that cause fear conditioning to be PR-dependent. Rats were conditioned to one of three cues: a multicall 19-kHz USV, a 19-kHz discontinuous tone, and a 19-kHz continuous tone. The discontinuous tone duplicated the on/off pattern of the individual calls in the USV, but it lacked the characteristic frequency modulations. Well-localized neurotoxic PR lesions impaired conditioning to the USV, the discontinuous tone, and the training context. However, PR lesions had no effect on conditioning to the continuous tone. The authors suggest that the lesion effects on fear conditioning to both cues and contexts reflect the essential role of PR in binding stimulus elements together into unitary representations.

Molecular and epidemiological evidence of patient-to-patient hepatitis C virus transmission in a Scottish emergency department.

BACKGROUND: Transmission of hepatitis C virus (HCV) in the healthcare setting is rare. Routine infection prevention and control measures mean that this should be a preventable 'never event'. AIM: To investigate the diagnosis of acute healthcare-associated HCV infection. METHODS: Epidemiological and molecular investigation of a case of acute HCV infection associated with nosocomial exposure. FINDINGS: Detailed investigation of the treatment history of a patient with acute HCV infection identified transmission from a co-attending patient in an emergency department as the likely source; this possibility was confirmed by virus sequence analysis. The precise route of transmission was not identified, though both patient and source had minimally invasive healthcare interventions. Review of infection, prevention and control identified potentially contributory factors in the causal pathway including hand hygiene, inappropriate use of personal protective equipment, and blood contamination of the surface of the departmental blood gas analyser. CONCLUSION: We provide molecular and epidemiological evidence of HCV transmission between patients in an emergency department that was made possible by environmental contamination. Patients with HCV infection are higher users of emergency care than the general population and a significant proportion of those affected remain unknown and/or infectious. Equipment, departmental design, staff behaviour, and patient risk require regular review to minimize the risk of nosocomial HCV transmission.

Role of plasma gelsolin and the vitamin D-binding protein in clearing actin from the circulation.

We determined the plasma kinetics of both actin and complexes of actin with the two high affinity actin-binding proteins of plasma, gelsolin, and vitamin D-binding protein (DBP). Actin is cleared rapidly from the plasma by the liver (half-disappearance time, 0.5 h). Using radiolabeled actin-binding proteins, we found that actin accelerated the clearance of both plasma gelsolin and the vitamin D-binding protein. In separate experiments we found that DBP-actin complexes were cleared more quickly than gelsolin-actin complexes, at a rate comparable to the clearance of actin from the blood. A low affinity interaction (dissociation constant, 2.9 X 10(-4) M) between actin and fibronectin was found, suggesting that little actin will bind to fibronectin in plasma. We conclude that while plasma gelsolin and DBP may both clear actin from the circulation, DBP appears to play a more important role. By so doing, DBP may conserve the filament-severing activity of plasma gelsolin.

Multiple orifice distribution system for placing green lacewing eggs into verticel larval rearing units.

Green lacewings are widely used biological control agents for various insect pests. To meet the needs of growers, green lacewings are being mass-reared commercially around the world. A common salt shaker has been used regularly to distribute eggs into Verticel lacewing larval rearing units. This technique is time consuming and inefficient because the number of eggs distributed in each cell is inconsistent. The multiple orifice distribution (MOD) system described here greatly improved egg distribution efficiency by increasing the percentage of Verticel cells containing the desired one to four eggs per cell (i.e., 40.8 and 52.1% by using salt shaker method versus 61.9% by using the MOD system). This mechanical system significantly reduced the labor and time involved in the process and would cost under $3500. In addition, this new system could be modified for distribution of other insect eggs.

Validation of feed and manure data collected on Wisconsin dairy farms.

An on-farm study of 54 representative Wisconsin dairy farms was conducted to evaluate the influence of biophysical and socioeconomic factors on overall feed, fertilizer, and manure nutrient use. This report validates 1) how well data on cow diets, feed analyses, and milk production reflected established feed-milk-manure relationships; and 2) how well farmer-recorded data on manure land application reflected literature values of manure N and P excretion, collection, and loss. Calculated feed N and P use efficiencies (18 to 33% and 18 to 35%, respectively) fell within ranges expected for dairy farms. This suggested that our on-farm methods of data collection provided reliable information on relationships among feed N and P intake, secretions in milk, and excretion in manure. On stanchion farms, there were no differences between farmer estimates (kg/farm) of manure P collected (1,140) and land-applied (1,210) and what would be calculated from the literature (1,340). On freestall farms, there were no differences in amounts (kg/farm) of manure P collected (2,889), land-applied (2,350), or literature estimates (2,675). Manure P applications (kg/ha) to tilled cropland would be similar using either farmer estimates of manure collected and land-applied, or literature estimates. The data provided a snapshot of Wisconsin industry practices, as well as information on the range of feed and manure management practices on individual dairy farms. Improvements to data collection methods would require increased skill and training of both farmers and those responsible for assisting farmers in on-farm data collection and analyses.

Nucleotide sequence organisation in the rye genome.

Nucleotide sequence organisation in the genome of rye, Secale cereale, has been studied using renaturation kinetics and S1 nuclease digestion of the renatured products. Approximately 25 to 30% of the genome consists of very slowly renaturing, possibly single copy sequences. Most, if not all, of these sequences are interspersed between repeated sequences and are between 400 and 3500 nucleotide pairs long. Approximately 70 to 75% of the genome consists of repeated sequences. The more highly diverged repeated sequences (30% of the genome) which fail to renature under highly stringent renaturation conditions range from 500 to more than 5000 base pairs long and are interspersed in the chromosomes with less diverged repeated sequences (40% of the genome) which are usually less than 800 nucleotide pairs long. Four percent of the genome consists of very rapidly reannealing sequences which may be inverted duplications. These sequences may be in clusters distributed through at least 30% of the genome.

Endoscopic ultrasound-guided real-time fine-needle aspiration biopsy of the pancreas in cancer patients with pancreatic lesions.

BACKGROUND: Endoscopic ultrasound (EUS) is an important new tool in the staging of pancreatic malignancies. Using new curved linear-array instruments, real-time fine-needle aspiration biopsy (RTFNA) of pancreatic lesions can be performed. METHODS: Forty-five patients with pancreatic lesions (22 males and 23 females) underwent staging with the Olympus EUM-20 (Olympus America Corp, Melville, NY) followed by EUS-RTFNA with the Pentax FG-32PUA (Pentax-Precision Instrument Corp, Orangeburg, NY) and the 22-gauge GIP needle (GIP Medizin Technik, Grassau, Germany). RESULTS: EUS tumor stages were as follows: TO, n = 1; T1, n = 8; T2, n = 9; and T3 n = 27. Aspiration attempts were unsuccessful in four patients (two technical failures and two inadequate specimens). The remaining 41 lesions (mean size, 3.3 cm) were aspirated under EUS guidance (median passes, three) and the cytologic diagnoses were 25 definite adenocarcinoma, five suspicious for adenocarcinoma (three subsequently confirmed and two clinical course consistent with adenocarcinoma), and 11 negative for malignancy. Of 11 negatives, two were found to have adenocarcinoma, seven were confirmed benign at surgery (four cystadenomas and three inflammatory), one had a benign pseudocyst, and one had abundant inflammatory cells on RTFNA and follow-up time greater than 12 months with computed tomographic (CT) scans consistent with resolving inflammation. There were no false-positive RTFNAs. There were no procedure-related complications. Among those with diagnostic EUS-RTFNA (91%), the sensitivity for malignancy (confirmed plus suspicious) was 94% and negative predictive value 82%. CONCLUSION: EUS-guided RTFNA is a safe and accurate method for performing pancreatic biopsy. It should be considered in patients with suspected pancreatic malignancies in whom a tissue diagnosis is required or when other modalities have failed. EUS-RTFNA allows for local staging and tissue diagnosis in one procedure.

Variance component analysis of allozyme frequency data from eastern populations of Drosophila melanogaster.

Gene frequency variation at eight polymorphic allozyme loci in Drosophila melanogaster populations in North Carollina and the east coast of the United States were analyzed utilizing the variance component estimation procedures suggested by Cockerham (1969, 1973). These variance components were used to estimate correlations of genes within small geographic regions. The average (over loci) correlation between genes in the same individual within subpopulations was estimated to be 0.033. That between genes in the same subpopulation in different individuals was estimated to be very small, although significantly different from zero. The macrogeographic variation measured by the correlation of genes sampled from the same local region was large for some loci and smaller for others. this variation was also analyzed by correlation with latitude and longitude. Several previously recognized clines were identified as were several new clines.--These results were interpreted as indicating either some degree of nonrandom mating and local breeding unit isolation or a low frequency of null alleles. The geographic and temporal variation has no simple interpretation.

Methotrexate dosage reduction in patients with rheumatoid arthritis beginning therapy with infliximab: the Infliximab Rheumatoid Arthritis Methotrexate Tapering (iRAMT) trial.

OBJECTIVE: Infliximab plus methotrexate (MTX) is approved for the treatment of rheumatoid arthritis (RA). Based on the benefit/risk profile of this combination therapy, lower doses of MTX would be preferable when infliximab efficacy can be maintained. We evaluated the ability of patients receiving infliximab plus MTX to achieve and maintain a clinical response while the dose of MTX was tapered. METHODS: Infliximab infusions were administered at a minimum dosage of 3 mg/kg at 8-week intervals (following three loading doses at weeks 0, 2, and 6) to patients who had an inadequate response to MTX. MTX tapering was initiated at week 22 or later when at least a 40% improvement in the combined tender and swollen joint count was achieved; dosages were reduced by 5 mg every 8 weeks to a protocol-specified minimum dosage of 5 mg per week. If the required dosage of MTX after a flare was greater than the baseline dosage, the patient was considered a treatment failure. RESULTS: Of the 210 patients enrolled, 159 (76%) achieved a 40% or better improvement in the combined tender and swollen joint count and had their MTX doses tapered. In these 159 responders, the median (mean) dose of MTX was reduced from 15 (16.5) mg per week at baseline to 5 (7.1) mg per week at week 54. From the time of initial response, 79% of these patients had a zero- or a one-vial increase in infliximab, corresponding to an approximate dose increase of 1 mg/kg, through week 54. CONCLUSION: Approximately 75% of the patients participating in this trial achieved at least a 40% reduction in the combined swollen and tender joint count (correlating with an American College of Rheumatology 20% [ACR20] response in 83% of patients) while reducing the mean MTX dose by 57%.

Manure collection and distribution on Wisconsin dairy farms.

Manure management plans require knowing the amount of manure produced, collected, and available for land-spreading. Whereas much information is available to calculate manure production, little is known about the types and amounts of manure actually collected on typical dairy farms. This study of 54 representative Wisconsin dairy farms showed significant regional, housing, and herd size differences in collection of manure from lactating cows (Bos taurus), dry cows, and heifers. Significantly (P < 0.05) less manure is collected in the hilly southwest (56% of total annual herd production) than in the undulating south central (72%) or the flat northeast (68%) regions. Collection of lactating cow manure is significantly (P < 0.05) lower from stanchion (66% of total annual production) than free-stall (89%) housing, and significant (P < 0.05) positive relationships were found between the number of lactating cows a farm keeps and the percentage manure collected. Average annual manure N (range of 116-846 kg N ha(-1)) and P (range of 24-158 kg P ha(-1)) loading rates in areas where manure goes uncollected was highest in unvegetated barnyards followed by vegetated and partially vegetated outside areas. Once uncollected manure was accounted for, average annual loading rates on cereal cropland ranged from 128 to 337 kg ha(-1) of manure N, and from 45 to 139 kg ha(-1) of manure P. Compared with adjacent cropland, the accumulation of uncollected manure has vastly increased soil test P, K, and organic matter levels in outside areas. Manure management on Wisconsin dairy farms with small to medium herds might require assistance in managing manure in outside confinement areas to reduce the risk of impairing surface and ground water quality.

In vivo expression of full-length human dystrophin from adenoviral vectors deleted of all viral genes.

Adenoviral vectors have been shown to effect efficient somatic gene transfer in skeletal muscle and thus offer potential for the development of therapy for Duchenne muscular dystrophy (DMD). Efficient transfer of recombinant genes has been demonstrated in skeletal muscle using recombinant adenoviruses deleted of E1. Application of this vector system to the treatment of DMD is limited by the vector immunogenicity, as well as by size constraints for insertion of recombinant genes, precluding the incorporation of a full-length dystrophin minigene construct. We describe in this study the use of helper adenovirus to generate a recombinant vector deleted of all viral open reading frames and containing a full-length dystrophin minigene. We show that this deleted vector (delta vector) is capable of efficiently transducing dystrophin in mdx mice, in myotubes in vitro and muscle fibers in vivo. Our modification of adenoviral vector technology may be useful for the development of gene therapies for DMD and other diseases.