Cleavage of HIV-1 gag polyprotein synthesized in vitro: sequential cleavage by the viral protease

The virally encoded protease of human immunodeficiency virus is responsible for the processing of the gag and gag-pol polyprotein precursors to their mature polypeptides. Since correct processing of the viral polypeptides is essential for the production of infectious virus, HIV protease represents a potential target for therapeutic agents that may prove beneficial in the treatment of AIDS. In this study, full-length gag polyprotein has been synthesized in vitro to serve as a substrate for bacterially expressed HIV-1 protease. Expression of the protease in E. coli from the lac promoter was enhanced approximately five-fold by deletion of a potential hairpin loop upstream from the codon determining the amino terminus of mature protease. Extracts of induced cultures of E. coli harboring a protease-containing plasmid served as the source of protease activity. The gag polyprotein synthesized in vitro was cleaved by such lysates, producing fragments corresponding in size to p17 plus p24 and mature p24. Immunoprecipitations with monoclonal antibodies to p17 and p24 polypeptides suggest that initial cleavage of gag polyprotein occurs near the p24-p15 junction. The proteolysis was inhibited by pepstatin with an IC50 of 0.15 mM for cleavage at the p24-p15 junction and 0.02 mM for cleavage at the p17-p24 junction.

Regulation of purine metabolism by plasma membrane and cytoplasmic 5'-nucleotidases

The contribution of plasma membrane 5'-nucleotidase (E.C. 3.1.3.5) to intracellular purine degradation and release was evaluated in cultured human lymphoblasts. B-lymphoblasts and T-lymphoblasts are characterized by high and low levels of plasma membrane 5'-nucleotidase activity, respectively. After radiolabeling of the cellular adenine nucleotide pools with [8-14C]adenine, deoxyglucose-induced purine nucleotide degradation resulted in a 2-2.5 times greater release of cellular radioactivity from the B-lymphoblasts than from the T-lymphoblasts. Specific inhibition of plasma membrane 5'-nucleotidase with 50 microM alpha, beta-methylene adenosine diphosphate (AMPCP) did not decrease purine release during deoxyglucose-induced nucleotide degradation. Similarly, the inhibition of B-lymphoblast membrane 5-nucleotidase did not alter the incorporation of [8-14C]adenine into the nucleotide pool. Therefore, to explain the relatively high release of purine nucleotide degradation products in B-lymphoblasts when compared with T-lymphoblasts, cytoplasmic 5'-nucleotidase activity was investigated in these cell lines. B-lymphoblasts have seven times more cytoplasmic 5'-nucleotidase activity for dAMP and two to three times more activity for other purine nucleoside 5'-monophosphates than do T-lymphoblasts at pH 7.4. Membrane and cytoplasmic nucleotidase activities are produced by different enzymes that can be distinguished by differences in pH optima, Michaelis constants for purine substrates, divalent cation requirements, and susceptibilities to AMPCP inhibition. The data suggest that plasma membrane 5'-nucleotidase hydrolyzes extracellular nucleoside 5'-monophosphates only. Cytoplasmic 5'-nucleotidase most likely regulates the degradation of intracellular nucleoside 5'-monophosphates and may be responsible for the increased purine release observed in B-lymphoblasts.

Prospective evaluation of a new sternal closure method with thermoreactive clips

OBJECTIVES

The role of the sternal closure techniques on the incidence of sternal dehiscence and wound infection are well defined among a high number of other variables involved. In the various series, the incidence of wound complication in cardiac surgery varies from 2 to 8%. The aim of our study is to evaluate the role of thermal-dependent shape-memory Nitillium clips in reducing the incidence of sternal dehiscence following sternotomy.

METHODS

We perspectively randomized 1000 consecutive patients requiring cardiac surgery to evaluate the incidence of sternal wound complications (SWC), sternal dehiscence and/or other related complications. We compared Group I (500 patients), in which sternal closure was achieved with standard sternal wires, with Group II (500 patients), in which sternal approximation was carried out by means of thermoreactive Nitillium clips. The two randomized groups were comparable in terms of age, gender, Euroscore and risk factors for sternal/wound complications.

RESULTS

In our study the overall incidence of SWC was 4.7%. The incidence of SWC was considerably higher in Group I (6.8%) when compared to Group II (2.6%) (P=0.003). Mechanical sternal dehiscence without infection occurred in 14 patients in Group I and in one patient in Group II (P=0.002). Despite sternotomy wound infection occurred similarly in both groups (15 patients in Group I vs. 12 patients in Group II), sternal revision was performed only in patients of Group I (Group I: 9/15 vs. Group II: 0/12; P=0.001).

CONCLUSION

Thermal shape-memory Nitillium clips provided superior results in sternal osteosynthesis following midline sternotomy, due to a considerable reduction of sternal dehiscence and related complications. The clinical benefit of Nitillium clips was demonstrated even in patients with several risk factors for SWC.

Radiographic study of bit position within the horse's oral cavity

The objective was to describe and compare the positions of different types of bits within the horse's oral cavity. Eight horses were fitted with a bridle and six bits [jointed snaffle ( JS), Boucher, KK Ultra, Myler snaffle (MylerS), Myler ported barrel (MylerPB), Myler correctional-ported barrel (MylerCPB)]. Lateral radiographs and custom software were used to measure the position and orientation of the bits relative to the horse's palate and second premolar teeth without rein tension and with 25±5 N bilateral rein tension. The results showed differences in the position of the bits within the horse's oral cavity and in their movements in response to rein tension. Without rein tension, single-jointed bits were further from the premolar teeth ( JS 32.2±10.6 mm; Boucher 33.9±10.8 mm) than the Myler bits (MylerS 20.2±9.7 mm; MylerPB 12.8±6.7 mm; MylerCPB 14.6±4.3 mm). Single-jointed bits moved closer to the premolars when tension was applied to the reins (JS 20.8±6.3 mm; Boucher 19.7±6.8 mm). The cannons of the Boucher were more elevated than those of the other bits. The cannon angulation decreased significantly from 38.7±13.7 deg. to 21.6±6.9 deg. for JS and from 43.1±10.1 deg. to 27.8±10.1 deg. for the Boucher when tension was applied to the reins. The Myler bits showed minimal change in position in response to the application of rein tension.

Systemic leukocyte filtration during cardiopulmonary bypass

Cardiopulmonary bypass (CPB) induces a whole body inflammatory response leading to postoperative lung dysfunction. Activated leukocytes may play a role in the pathogenesis of pulmonary dysfunction. We evaluated postoperative lung function after the use of leukocyte-depleting filters incorporated in the extracorporeal circuit during CPB. From November 1997 to March 2000, 40 patients underwent isolated coronary artery bypass grafting. Patients were randomly allocated to the leukocyte-depletion group (group F, 20 patients) or to the control group (group C, 20 patients). There was no significant difference between the two groups with respect to age, sex, weight, height, body surface area, haemoglobin and haematocrit levels, preoperative left ventricular ejection fraction, cooling temperature, aortic crossclamping and CBP duration. Blood samples were drawn preoperatively, at aortic declamping, 60 min after CPB, after arriving at the intensive care unit (ICU) and 24 h after the operation. We analysed blood cell count, elastase, interleukin-8 (IL-8) and tumour necrosis factor (TNF-alpha) levels and continuous monitoring of arterial blood gases in the intensive care unit (ICU). The analysis of total circulating white blood cells (WBCs) showed a significant reduction of WBCs in both groups soon after aortic declamping [from the right atrium: 6.4 x 10(9)/l +/- 1.4 x 10(9)/l in group F vs 10.3 +/- 1.8 x 10(9)/l in group C (p<0.05); from the left atrium: 5.8 +/- 1.3 x 10(9)/l in group F vs 8.4 +/- 1.9 x 10(9)/l in group C (p<0.05)] and after 60 min of CPB [7.1 +/- 2.2 x 10(9)/l in group F vs 10.4 +/- 1.8 x 10(9)/l in group C (p<0.05)]. The analysis of circulating neutrophils showed similar findings in both groups. Elastase levels increased during CPB in both groups with a peak at the end of CPB without significant difference between the two groups (group C: 260 +/- 148 microg/l vs group F: 371 +/- 68 microg/l). The decrease of plasmatic elestase levels was observed, for both groups, in the 24 h after CPB. There was no difference in intubation time between the two groups (16.4 h for group C vs 11.2 h for group F). Pulmonary function tested by pulmonary respiratory index [RI = partial pressure of oxygen/fraction of inspired oxygen (PaO2/FiO2 x 100)] did not show significant difference between the two groups, either arriving in the ICU (group C RI 265 vs group F RI 322), or after 3 h (group RI 304 vs group F RI 305) or after 6 h (group C RI 292 vs group F RI 319). Leukocyte-depleting filters reduce with blood cells count during CPB, but, in this study, WBC depletion did not significantly improve clinical conditions or laboratory finding.

Probing the Symmetry Energy with the Spectral Pion Ratio

Many neutron star properties, such as the proton fraction, reflect the symmetry energy contributions to the equation of state that dominate when neutron and proton densities differ strongly. To constrain these contributions at suprasaturation densities, we measure the spectra of charged pions produced by colliding rare isotope tin (Sn) beams with isotopically enriched Sn targets. Using ratios of the charged pion spectra measured at high transverse momenta, we deduce the slope of the symmetry energy to be 42<L<117  MeV. This value is slightly lower but consistent with the L values deduced from a recent measurement of the neutron skin thickness of ^{208}Pb.

Effects of different bits and bridles on frequency of induced swallowing in cantering horses

It has been suggested that the presence of a bit reflexly increases salivation but, at the same time, interferes with the horse's ability to swallow. The objective of this study was to compare swallowing frequency in 12 horses exercising at canter while wearing a head collar, a bitless bridle, a jointed snaffle bit and a Myler correctional-ported barrel bit. Laryngeal movements were recorded videoendoscopically as the horses cantered (8 m s−1) on a high speed treadmill, with the use of side reins to flex the poll. Swallowing was stimulated artificially by infusion of sterile water at a constant rate of 5 ml min−1 through a cannula in the endoscope's biopsy port. The results showed large differences in swallowing frequency between horses. Swallowing frequency was lower for the Myler snaffle than for the other conditions (P<0.05). It is concluded that the presence of a bit does not preclude swallowing during exercise at canter with the poll in a flexed position, but certain types of bits may be associated with a reduction in swallowing frequency.

Evaluation of the Structure of Myodural Bridges in an Equine Model of Ehlers-Danlos Syndromes

Myodural bridges have been described in various species as connective tissue structures “bridging” small cranio-cervical muscles to the dura. Myodural bridges are thought to stabilize the dural sac during head and neck movements and promote cerebrospinal fluid motion; however, their role in neurological diseases has not yet been established. We report ultrasonographic visualization, necropsy, histopathologic and ultrastructural findings of myodural bridges in horses with hereditary equine regional dermal asthenia (HERDA), an equine model of Ehlers-Danlos syndromes. Five HERDA and 5 control horses were studied. Post-mortem examination and ultrasonographic studies (3 HERDA and 4 controls) demonstrated that the atlanto-occipital and atlanto-axial myodural bridges are dynamic structures “moving” the dura. En block resection of the myodural bridges (4 HERDA and 5 controls) was accomplished and histopathology showed myofiber degeneration in 3 HERDA horses and 1 control. Ultrastructural examination revealed loosely packed collagen fibrils with abnormal orientation in all HERDA horses compared to mild abnormalities in 2 controls. Our study provides necropsy and ultrasonographic evidence of the dynamic aspect of the myodural bridges as dural sac stabilizers. Myodural bridges may be pathologically altered in connective tissue disease as evidenced by the ultrastructural morphology in the HERDA myodural bridge.

Return to Sport after Injury: A Web-Based Survey of Owners and Handlers of Agility Dogs

Objective Internet-based surveys of canine agility injury rates have been performed, but unlike with equine and human competition, there is a paucity of data on return to sport of agility dogs after orthopaedic injury. This study aimed to gather initial information on canine return to competition.

Methods Data were collected using an internet-based 18-question survey of 427 dogs from around the world (92.4% North America). Relationships between categorical variables and return to sport were assessed with descriptive statistics, a chi-squared or Fischer's exact test. Categorical variables included breed, sex, age, surgery, stifle versus shoulder surgery, stifle versus all other types of surgery and drop in competition class. Significance was set at p≤ 0.05.

Results Of 427 completed surveys, age, sex and breed were not significantly associated with return to competition. Overall, 67.4% of dogs returned to competition post-orthopaedic injury, but jump height was lowered in 47% of cases. Dogs were returned to competition post-stifle surgery, but were the least likely of all injury types to return to competition (p = 0.044) and were more likely to compete at a lower class (p = 0.026).

Clinical Significance While over half of all dogs returned to competition, just under half of that group decreased jump class. Dogs that have undergone stifle surgery have the worst prognosis for return to agility and if they return, they are more likely to drop class.

Observation of the Exotic Isotope ^{13}F Located Four Neutrons beyond the Proton Drip Line

A ^{13}F resonance was observed following a charge-exchange reaction between a fast ^{13}O beam and a ^{9}Be target. The resonance was found in the invariant-mass distribution of 3p+^{10}C events and probably corresponds to a 5/2^{+} excited state. The ground state was also expected to be populated, but was not resolved from the background. The observed level decays via initial proton emissions to both the ground and first 2^{+} state of ^{12}O, which subsequently undergo 2p decay. In addition, there may also be a significant proton decay branch to the second 2^{+} level in ^{12}O. The wave function associated with the observed level may be collectivized due to coupling to the continuum as is it located just above the threshold for proton decay to the 2_{2}^{+} state of ^{12}O.

Observation of long-range three-body coulomb effects in the decay of (16)Ne

The interaction of an E/A=57.6-MeV ^{17}Ne beam with a Be target is used to populate levels in ^{16}Ne following neutron knockout reactions. The decay of ^{16}Ne states into the three-body ^{14}O+p+p continuum is observed in the High Resolution Array (HiRA). For the first time for a 2p emitter, correlations between the momenta of the three decay products are measured with sufficient resolution and statistics to allow for an unambiguous demonstration of their dependence on the long-range nature of the Coulomb interaction. Contrary to previous measurements, our measured limit Γ<80  keV for the intrinsic decay width of the ground state is not in contradiction to the small values (of the order of keV) predicted theoretically.

Democratic decay of 6Be exposed by correlations

The interaction of an E/A=70-MeV (7)Be beam with a Be target was used to populate levels in (6)Be following neutron knockout reactions. The three-body decay of the ground and first excited states into the α+p+p exit channel were detected in the High Resolution Array. Precise three-body correlations extracted from the experimental data allowed us to obtain insight into the mechanism of the three-body democratic decay. The correlation data are in good agreement with a three-cluster-model calculation and thus validate this theoretical approach over a broad energy range.

Owner Perceptions of Long-Term Systemic Use of Subcutaneous Administration of Polysulfated Glycosaminoglycan

Polysulfated glycosaminoglycan (PSGAG) is a slow-acting disease-modifying agent used to treat degenerative joint disease. Although labeled for intramuscular use, it is commonly given by owners via a subcutaneous (SC) route. There is little information on adverse events related to SC administration or what other therapies are used concurrently with PSGAG. We hypothesized that SC PSGAG is perceived by owners as having minimal adverse events and that it would most often be given with other therapies. Owners (n = 378) were surveyed about their perceptions regarding SC PSGAG prescribed to dogs at one veterinary rehabilitation clinic. Complete surveys were provided for 69 dogs (two owners had multiple dogs). Overall, 13/69 (18.8%) dogs had an adverse event reported during the use of PSGAG. Most events were considered minor (stomach upset, loose stool, pain at injection site, fear) and did not lead to discontinuation of PSGAG. One dog experienced a moderate adverse event (persistent gastrointestinal symptoms) and one a severe adverse event (thrombocytopenia, bruising), which resolved after discontinuing PSGAG. PSGAG is most commonly administered along with other medications and rehabilitation therapies. The present study demonstrates that SC administration of PSGAG is well tolerated in most of the dogs, with primarily mild, self-resolving adverse events.

First Observation of Unbound ^{11}O, the Mirror of the Halo Nucleus ^{11}Li

The structure of the extremely proton-rich nucleus _{8}^{11}O_{3}, the mirror of the two-neutron halo nucleus _{3}^{11}Li_{8}, has been studied experimentally for the first time. Following two-neutron knockout reactions with a ^{13}O beam, the ^{11}O decay products were detected after two-proton emission and used to construct an invariant-mass spectrum. A broad peak of width ∼3.4  MeV was observed. Within the Gamow coupled-channel approach, it was concluded that this peak is a multiplet with contributions from the four lowest ^{11}O resonant states: J^{π}=3/2_{1}^{-}, 3/2_{2}^{-}, 5/2_{1}^{+}, and 5/2_{2}^{+}. The widths and configurations of these states show strong, nonmonotonic dependencies on the depth of the p-^{9}C potential. This unusual behavior is due to the presence of a broad threshold resonant state in ^{10}N, which is an analog of the virtual state in ^{10}Li in the presence of the Coulomb potential. After optimizing the model to the data, only a moderate isospin asymmetry between ground states of ^{11}O and ^{11}Li was found.

Ultrasonographic appearance of supraspinatus and biceps tendinopathy improves in dogs treated with low-intensity extracorporeal shock wave therapy: a retrospective study

Objective

This study aimed to determine whether dogs with shoulder tendinopathy diagnosed via musculoskeletal ultrasound would show improvement in imaging after treatment using piezoelectric shockwave therapy and rest.

Methods

Medical records were reviewed for dogs diagnosed with biceps and/or supraspinatus tendinopathy via musculoskeletal ultrasound, treated using piezowave shockwave, and re-imaged post-treatment. Data collected included patient signalment, duration and grade of lameness, prior rest, piezowave dose, and patient outcome, including a return to sport where applicable. Images were scored using an adapted ultrasound grading scale, in addition to obtaining cross-sectional area measurements. Statistics included Shapiro-Wilk tests (normality), Wilcoxon matched pairs signed rank tests (pre- vs. post-treatment comparisons), and Spearman's correlation coefficients (lameness grade vs. ultrasound score) (significant at P < 0.05).

Results

In total, 26 of 30 dogs had pathology involving both the biceps and supraspinatus tendons in one limb, with 27 of 30 having tendon/s affected bilaterally. For both tendons, post-treatment cross-sectional area and ultrasound score were significantly lower than pre-treatment (P < 0.001). Lameness decreased clinically (P < 0.0001) following piezowave shockwave treatment regardless of the tendons involved, but the lameness score did not correlate with the ultrasound score for either tendon.

Conclusion

Dogs with tendinopathy of the biceps brachii and supraspinatus showed significant improvement on follow-up musculoskeletal ultrasound and lameness evaluation after the treatment of their tendons using piezoelectric shockwave therapy with rest.

Clinical significance

Canine biceps brachii and supraspinatus tendinopathy can cause variable lameness and ultrasonographic appearance, which improves after shockwave therapy and rest. The ultrasound scoring system and cross-sectional area assessment provide useful outcome measures for clinical cases.

Strong Evidence for ^{9}N and the Limits of Existence of Atomic Nuclei

The boundaries of the chart of nuclides contain exotic isotopes that possess extreme proton-to-neutron asymmetries. Here we report on strong evidence of ^{9}N, one of the most exotic proton-rich isotopes where more than one half of its constitute nucleons are unbound. With seven protons and two neutrons, this extremely proton-rich system would represent the first-known example of a ground-state five-proton emitter. The invariant-mass spectrum of its decay products can be fit with two peaks whose energies are consistent with the theoretical predictions of an open-quantum-system approach; however, we cannot rule out the possibility that only a single resonancelike peak is present in the spectrum.

Owner Perceptions of Long-Term Systemic Use of Subcutaneous Administration of Polysulfated Glycosaminoglycan

Polysulfated glycosaminoglycan (PSGAG) is a slow-acting disease-modifying agent used to treat degenerative joint disease. Although labeled for intramuscular use, it is commonly given by owners via a subcutaneous (SC) route. There is little information on adverse events related to SC administration or what other therapies are used concurrently with PSGAG. We hypothesized that SC PSGAG is perceived by owners as having minimal adverse events and that it would most often be given with other therapies. Owners (n = 378) were surveyed about their perceptions regarding SC PSGAG prescribed to dogs at one veterinary rehabilitation clinic. Complete surveys were provided for 69 dogs (two owners had multiple dogs). Overall, 13/69 (18.8%) dogs had an adverse event reported during the use of PSGAG. Most events were considered minor (stomach upset, loose stool, pain at injection site, fear) and did not lead to discontinuation of PSGAG. One dog experienced a moderate adverse event (persistent gastrointestinal symptoms) and one a severe adverse event (thrombocytopenia, bruising), which resolved after discontinuing PSGAG. PSGAG is most commonly administered along with other medications and rehabilitation therapies. The present study demonstrates that SC administration of PSGAG is well tolerated in most of the dogs, with primarily mild, self-resolving adverse events.

Functional contexts of adipose and gluteal muscle tissue gene co-expression networks in the domestic horse

A gene's response to an environment is tightly bound to the underlying genetic variation present in an individual's genome and varies greatly depending on the tissue it is being expressed in. Gene co-expression networks provide a mechanism to understand and interpret the collective transcriptional responses of genes. Here, we use the Camoco co-expression network framework to characterize the transcriptional landscape of adipose and gluteal muscle tissue in 83 domestic horses (Equus caballus) representing 5 different breeds. In each tissue, gene expression profiles, capturing transcriptional response due to variation across individuals, were used to build two separate, tissue-focused, genotypically-diverse gene co-expression networks. The aim of our study was to identify significantly co-expressed clusters of genes in each tissue, then compare the clusters across networks to quantify the extent that clusters were found in both networks as well as to identify clusters found in a single network. The known and unknown functions for each network were quantified using complementary, supervised and unsupervised approaches. First, supervised ontological enrichment was utilized to quantify biological functions represented by each network. Curated ontologies (GO and KEGG) were used to measure the known biological functions present in each tissue. Overall, a large percentage of terms (40.3% of GO and 41% of KEGG) were co-expressed in at least one tissue. Many terms were co-expressed in both tissues, however a small proportion of terms exhibited single tissue co-expression suggesting functional differentiation based on curated, functional annotation. To complement this, an unsupervised approach not relying on ontologies was employed. Strongly co-expressed sets of genes defined by Markov clustering identified sets of unannotated genes showing similar patterns of co-expression within a tissue. We compared gene sets across tissues and identified clusters of genes the either segregate in co-expression by tissue or exhibit high levels of co-expression in both tissues. Clusters were also integrated with GO and KEGG ontologies to identify gene sets containing previously curated annotations versus unannotated gene sets indicating potentially novel biological function. Coupling together these transcriptional datasets, we mapped the transcriptional landscape of muscle and adipose setting up a generalizable framework for interpreting gene function for additional tissues in the horse and other species.