Efficient Ab Initio Multiplet Calculations for Magnetic Adatoms on MgO.

Scanning probe microscopy and spectroscopy, and more recently, single-atom electron spin resonance, have allowed the direct observation of electron dynamics at the atomic limit. The interpretation of data is strongly dependent on model Hamiltonians. However, fitting effective spin Hamiltonians to experimental data lacks the ability to explore a vast number of potential systems of interest. By using plane-wave density functional theory as starting point, we build a multiplet Hamiltonian making use of maximally localized Wannier functions. The Hamiltonian contains spin-orbit and electron-electron interactions needed to obtain the relevant spin dynamics. The resulting reduced Hamiltonian is solved by exact diagonalization. We compare three prototypical cases of 3d transition metals Mn (total spin S = 5/2), Fe (S = 2), and Co (S = 3/2) on MgO with experimental data and find that our calculations can accurately predict the spin orientation and anisotropy of the magnetic adatom. Our method does not rely on experimental input and allows us to explore and predict the fundamental magnetic properties of adatoms on surfaces.

Electronic medical record-based interventions to encourage opioid prescribing best practices in the emergency department.

OBJECTIVE: Overdose from opioids has reached epidemic proportions. Large healthcare systems can utilize existing technology to encourage responsible opioid prescribing practices. Our study measured the effects of using the electronic medical record (EMR) with direct clinician feedback to standardize opioid prescribing practices within a large healthcare system. METHODS: This retrospective multicenter study compared a 12 month pre- and post-intervention in 14 emergency departments after four interventions utilizing the EMR were implemented: (1) deleting clinician preference lists, (2) defaulting dose, frequency, and quantity, (3) standardizing formulary to encourage best practices, and (4) creating dashboards for clinician review with current opioid prescribing practices. Outlying clinicians received feedback through email and direct counseling. Total number of opioid prescriptions per 100 discharges pre- and post-intervention were recorded as primary outcome. Secondary outcomes included number of prescriptions per 100 discharges/clinician exceeding 3-day supply (defined as 12 tablets), number exceeding 30 morphine equivalent daily dose (MEDD)/day, and number of non-formulary prescriptions. RESULTS: There were >700,000 discharges during pre- and post-intervention periods. Percentage of total number opioid prescriptions per 100 discharges decreased from 14.4% to 7.4%, a 7.0% absolute reduction, (95% CI,6.9%-7.2%). There was a 5.9% to 0.7% reduction in prescriptions exceeding 3-days, (95% CI, 5.1%-5.3%), a 4.3% to 0.3% reduction in prescriptions exceeding 30 MEDD, (95% CI, 3.9%-4.0%), and a 0.3% to 0.1% reduction in non-formulary prescriptions, (95% CI, 0.2%-0.3%). CONCLUSIONS: A multi modal approach using EMR interventions which provide real time data and direct feedback to clinicians can facilitate appropriate opioid prescribing.

Electrochemiluminescent (ECL) [Ru(bpy)3](2+)/PAMAM dendrimer reactions: coreactant effect and 5-fluorouracil/dendrimer complex formation.

Electrogenerated chemiluminescence (ECL) reactions between tris(2,2'-bipyridine)ruthenium(II) and PAMAM dendrimers of the full (G1.0) and half (G1.5) generations were carried out in an aqueous medium at pH 6.1 and 10.0. In the absence of 5-fluoro-1H,3H-pyrimidine-2,4-dione (5-fluorouracil, 5-Fu) (coreactant effect study), the ECL efficiency trends as a function of [G1.0] and [G1.5] at pH 6.1 and 10.0 revealed that PAMAM dendrimers are about 100 (G1.5, pH 6.1), 60 (G1.5, pH 10.0), 26 (G1.0, pH 10.0) and 13 (G1.0, pH 6.1) times more efficient as ECL coreactants than oxalate anion is. Moreover, ECL reactions were done in the presence of several solutions of 5-Fu at a fixed concentration of the G1.0 and G1.5 dendrimers at pH 6.1 and 10.0 (binding study). The ECL efficiency trends as a function of [5-Fu] highlighted a dendrimer/5-Fu binding. Therefore, one of the most remarkable and novel findings of this work is the potential of PAMAM dendrimers to be used as both sensors and biosensors in an aqueous medium in the presence of a suitable sensitizer. Redox potentials of the [Ru(bpy)3](3+/2+) couple were also determined in the absence and presence of 5-Fu at both pHs. In the absence of 5-Fu the positive or negative shift of redox potentials showed the influence of the repulsive or attractive electrostatic long-range and short-range interactions between the charged dendrimer surface and the oxidized and reduced forms of the couple. In the presence of 5-Fu the trends of redox potentials highlighted the existence of a charged dendrimer/5-Fu species. Graphical Abstract ECL emission for the [Ru(bpy)3](2+)/ G1.0 dendrimer reaction in the presence of the 5-Fu at pH 6.1.

Presence of antibodies against Leptospira serovars in Chaetophractus villosus (Mammalia, Dasypodidae), La Pampa province, Argentina.

Leptospirosis is a zoonosis of worldwide distribution. The aim of this study was to examine the presence of antibodies against 21 Leptospira reactive serovars in Chaetophractus villosus in La Pampa province, Argentina, using the microscopic agglutination test (MAT). Pathologic changes compatible with leptospirosis and in situ detection of the agent by immunohistochemistry were studied in 24 and 3 individuals respectively. Only 35/150 (23.3%) serum samples had antibodies against Leptospira sp. Six percent of the samples reacted with serovar Canicola, 4.7% with serovar Castellonis, 1.3% with serovar Icterohemorrhagieae and 0.7% with serovar Hardjo. Sixteen (10.6%) serum samples agglutinated with Castellonis-Icterohemorrhagiae and Canicola-Castellonis serovars, both with 4.7%, and Canicola-Hardjo and Castellonis-Canicola-Icterohemorrhagiae both with 0.6%. Fourteen animals had variable degrees of lesions, which were more severe in animals with higher serological titers (3200), and Leptospira sp. was detected in 3 animals by immunohistochemistry. These results represent the first record of the presence of Leptospira in C. villosus in La Pampa.

Impact of Geriatric Consult Evaluations on Hospital Admission Rates for Older Adults.

Introduction: We examined the impact of a geriatric consult program in the emergency department (ED) and an ED observation geriatric care unit (GCU) setting on hospital admission rates for older ED patients. Methods: We performed a retrospective case control study from June 1-August 31, 2019 (pre-program) to September 24, 2019-January 31, 2020 (post-program). Post-program geriatric consults were readily available in the ED and required in the GCU setting. Hospital admission rates (outcome) are reported for patients who received a geriatric consult evaluation (intervention). We analyzed probability of admission using a mixed-effects logistic regression model that included age, gender, recent ED visit, Charlson Comorbidity Index, referral to ED observation, and geriatric consult evaluation as predictor variables. Results: A total of 9,663 geriatric ED encounters occurred, 4,042 pre-program and 5,621 post-program. Overall, ED admission rates for geriatric patients were similar pre- and post-program (44.8% vs 43.9%, P = 0.39). Of 243 geriatric consults, 149 (61.3%) occurred in the GCU. Overall admission rates post-program for patients receiving geriatric intervention were significantly lower compared to pre-program (23.4% vs 44.9%, P < 0.001). Post-program GCU hospital admission rates were significantly lower than pre-program ED observation unit admission rates (14/149, 9.4%, vs 111/477, 23.3%, P < 0.001). In the logistic regression model, admissions post-program were lower when a geriatric consult evaluation occurred (odds ratio [OR] 0.58, 95% confidence interval [CI] 0.41-0.83). Hospital admissions for older ED observation patients were also significantly decreased when a geriatric consult was obtained (GCU vs pre-program ED observation unit; OR 0.27, 95% CI 0.14-0.50). Conclusion: Geriatric consult evaluations were associated with significantly lower rates of hospital admission and persisted when controlled for age, gender, comorbidities, and ED observation unit placement. This model may allow healthcare systems to decrease potentially avoidable hospital admission rates in older ED patients.

Limited usefulness of the IS6110 touchdown-PCR in blood for tuberculin skin test false-negative cattle with serological response to Mycobacterium bovis.

Ante-mortem diagnosis of bovine tuberculosis (bTB) is based mainly on the tuberculin skin test (TST) and the ɣ-IFN release assay (IGRA). Some infected animals escape screening tests, thus, limit herd sanitation. Previous reports have suggested a predominant pattern of multi-organ lesions attributable to Mycobacterium bovis (the causative agent of bTB) bacteraemia. A case-control study was conducted to investigate blood PCR as an alternative tool for improving ante-mortem detection of TST false-negative bovines. Cases comprised 70 TST false-negative bovines (cases), which were serology positive, and controls included 81 TST positive bovines; all of them confirmed as infected with M. bovis. Detection of the IS6110 target through touchdown blood-PCR (IS6110 TD-PCR) was performed. The positivity of the blood-PCR was 27.2% in the control group. This performance was similar to the 15% obtained among cases (p = 0.134). Most cases identified by the IS6110 TD-PCR exhibited focalized lesions (p = 0.002). Results demonstrated that blood-PCR could detect TST false-negative cattle, even if they are negative for IGRA. Considering that cases exhibited humoral response to M. bovis, further studies conducted in a pre-serological stage could provide evidence about the real contribution of the technique in herds.

Ferromagnetism on an atom-thick & extended 2D metal-organic coordination network.

Ferromagnetism is the collective alignment of atomic spins that retain a net magnetic moment below the Curie temperature, even in the absence of external magnetic fields. Reducing this fundamental property into strictly two-dimensions was proposed in metal-organic coordination networks, but thus far has eluded experimental realization. In this work, we demonstrate that extended, cooperative ferromagnetism is feasible in an atomically thin two-dimensional metal-organic coordination network, despite only ≈ 5% of the monolayer being composed of Fe atoms. The resulting ferromagnetic state exhibits an out-of-plane easy-axis square-like hysteresis loop with large coercive fields over 2 Tesla, significant magnetic anisotropy, and persists up to TC ≈ 35 K. These properties are driven by exchange interactions mainly mediated by the molecular linkers. Our findings resolve a two decade search for ferromagnetism in two-dimensional metal-organic coordination networks.

Superior protection against paratuberculosis by a heterologous prime-boost immunization in a murine model.

Vaccination is the best strategy to control Paratuberculosis (PTB), which is a significant disease in cattle and sheep. Previously we showed the humoral and cellular immune response induced by a novel vaccine candidate against PTB based on the Argentinian Mycobacterium avium subspecies paratuberculosis (Map) 6611 strain. To improve 6611 immunogenicity and efficacy, we evaluated this vaccine candidate in mice with two different adjuvants and a heterologous boost with a recombinant modified vaccinia Ankara virus (MVA) expressing the antigen 85A (MVA85A). We observed that boosting with MVA85A did not improve total IgG or specific isotypes in serum induced by one or two doses of 6611 formulated with incomplete Freund's adjuvant (IFA). However, when 6611 was formulated with ISA201 adjuvant, MVA85A boost enhanced the production of IFNγ, Th1/Th17 cytokines (IL-2, TNF, IL-17A) and IL-6, IL-4 and IL-10. Also, this group showed the highest levels of IgG2b and IgG3 isotypes, both important for better protection against Map infection in the murine model. Finally, the heterologous scheme elicited the highest levels of protection after Map challenge (lowest CFU count and liver lesion score). In conclusion, our results encourage further evaluation of 6611 strain + ISA201 prime and MVA85A boost in bovines.

Agitation Management in the Emergency Department with Physical Restraints: Where Do These Patients End Up?

INTRODUCTION: Agitation is frequently encountered in the emergency department (ED) and can range from psychomotor restlessness to overt aggression and violent behavior. Among all ED patients, 2.6% present with agitation or become agitated during their ED visit. We aimed to determine ED disposition for patients requiring agitation management with physical restraints. METHODS: This was a retrospective cohort of all adult patients who presented to one of 19 EDs in a large integrated healthcare system and received agitation management with physical restraints between January 1, 2018-December 31, 2020. Categorical variables are presented as frequency and percentages, and continuous variables are presented as medians and interquartile range. RESULTS: There were 3,539 patients who had agitation management with physical restraints included in this study. In total 2,076 (58.8%) were admitted to the hospital (95% CI [confidence interval] 0.572-0.605), and of those 81.4% were admitted to a primary medical floor and 18.6% were medically cleared and admitted to a psychiatric unit. Overall, 41.2% were able to be medically cleared and discharged from the ED. Mean age was 40.9 years, 2,140 were male (59.1%), 1,736 were White (50.3%), and 1,527 (43%) were Black. We found 26% had abnormal ethanol, (95% CI 0.245-0.274) and 54.6% had an abnormal toxicology screen (95% CI 0.529-0.562). A significant number were administered a benzodiazepine or antipsychotic in the ED (88.44%) (95% CI 0.874-0.895). CONCLUSION: The majority of patients who had agitation management with physical restraints were admitted to the hospital; of those patients, 81.4% were admitted to a primary medical floor and 18.6% were admitted to a psychiatric unit.

Autologous Single Semitendinosus Anatomical Posterolateral Corner Reconstruction With Adjustable-Loop Cortical Suspension Devices.

We present our surgical technique for the reconstruction of the posterolateral corner of the knee. It is a tibia- and fibular-based reconstruction technique. Most of these procedures require the use of 2 tendons (autograft or allograft). In our technique, a single semitendinosus tendon is required, making the procedure more suitable if the surgeon prefers the use of autograft or when there is no access to a tissue bank. This is even more important in the setting of multiligament knee injuries. The most defining feature of this modification is the possibility of achieving the desired graft tension in a progressive and independent way, due to the use of 3 adjustable-loop cortical suspension devices.

Safety and efficacy of intra-arterial bone marrow mononuclear cell transplantation in patients with acute ischaemic stroke in Spain (IBIS trial): a phase 2, randomised, open-label, standard-of-care controlled, multicentre trial.

BACKGROUND: Pilot clinical trials have shown the safety of intra-arterial bone marrow mononuclear cells (BMMNCs) in stroke. However, the efficacy of different doses of intra-arterial BMMNCs in patients with acute stroke has not been tested in a randomised clinical trial. We aimed to show safety and efficacy of two different doses of autologous intra-arterial BMMNC transplantation in patients with acute stroke. METHODS: The IBIS trial was a multicentre phase 2, randomised, controlled, investigator-initiated, assessor-blinded, clinical trial, in four stroke centres in Spain. We included patients (aged 18-80 years) with a non-lacunar, middle cerebral artery ischaemic stroke within 1-7 days from stroke onset and with a National Institutes of Health Stroke Scale score of 6-20. We randomly assigned patients (2:1:1) with a computer-generated randomisation sequence to standard of care (control group) or intra-arterial injection of autologous BMMNCs at one of two different doses (2 × 106 BMMNCs/kg or 5 × 106 BMMNCs/kg). The primary efficacy outcome was the proportion of patients with modified Rankin Scale scores of 0-2 at 180 days in the intention-to-treat population, comparing each BMMNC dose group and the pooled BMMNC group versus the control group. The primary safety endpoint was the proportion of serious adverse events. This trial was registered at ClinicalTrials.gov, NCT02178657 and is completed. FINDINGS: Between April 1, 2015, and May 20, 2021, we assessed 114 patients for eligibility. We randomly assigned 77 (68%) patients: 38 (49%) to the control group, 20 (26%) to the low-dose BMMNC group, and 19 (25%) the high-dose BMMNC group. The mean age of participants was 62·4 years (SD 12·7), 46 (60%) were men, 31 (40%) were women, all were White, and 63 (82%) received thrombectomy. The median NIHSS score before randomisation was 12 (IQR 9-15), with intra-arterial BMMNC injection done a median of 6 days (4-7) after stroke onset. The primary efficacy outcome occurred in 14 (39%) patients in the control group versus ten (50%) in the low-dose group (adjusted odds ratio 2·08 [95% CI 0·55-7·85]; p=0·28), eight (44%) in the high-dose group (1·89 [0·52-6·96]; p=0·33), and 18 (47%) in the pooled BMMNC group (2·22 [0·72-6·85]; p=0·16). We found no differences in the proportion of patients who had adverse events or dose-related events, but two patients had a groin haematoma after cell injection in the low-dose BMMNC group. INTERPRETATION: Intra-arterial BMMNCs were safe in patients with acute ischaemic stroke, but we found no significant improvement at 180 days on the mRS. Further clinical trials are warranted to investigate whether improvements might be possible at different timepoints. FUNDING: Instituto de Salud Carlos III co-funded by the European Regional Development Fund/European Social Fund, Mutua Madrileña, and the Regional Ministry of Health of Andalusia.

Crystal orientation fabric anisotropy causes directional hardening of the Northeast Greenland Ice Stream.

The dynamic mass loss of ice sheets constitutes one of the biggest uncertainties in projections of ice-sheet evolution. One central, understudied aspect of ice flow is how the bulk orientation of the crystal orientation fabric translates to the mechanical anisotropy of ice. Here we show the spatial distribution of the depth-averaged horizontal anisotropy and corresponding directional flow-enhancement factors covering a large area of the Northeast Greenland Ice Stream onset. Our results are based on airborne and ground-based radar surveys, ice-core observations, and numerical ice-flow modelling. They show a strong spatial variability of the horizontal anisotropy and a rapid crystal reorganisation on the order of hundreds of years coinciding with the ice-stream geometry. Compared to isotropic ice, parts of the ice stream are found to be more than one order of magnitude harder for along-flow extension/compression while the shear margins are potentially softened by a factor of two for horizontal-shear deformation.

Discrimination of organic coffee via Fourier transform infrared-photoacoustic spectroscopy.

BACKGROUND: Procedures for the evaluation of the origin and quality of ground and roasted coffee are constantly needed for the associated industry due to complexity of the related market. Conventional Fourier transform infrared (FTIR) spectroscopy can be used for detecting changes in functional groups of compounds, such as coffee. However, dispersion, reflection and non-homogeneity of the sample matrix can cause problems resulting in low spectral quality. On the other hand, sample preparation frequently takes place in a destructive way. To overcome these difficulties, in this work a photoacoustic cell has been adapted as a detector in a FTIR spectrophotometer to perform a study of roasted and ground coffee from three varieties of Coffea arabica grown by organic and conventional methods. RESULTS: Comparison between spectra of coffee recorded by FTIR-photoacoustic spectrometry (PAS) and by FTIR spectrophotometry showed a better resolution of the former method, which, aided by principal components analysis, allowed the identification of some absorption bands that allow the discrimination between organic and conventional coffee. CONCLUSION: The results obtained provide information about the spectral behavior of coffee powder which can be useful for establishing discrimination criteria. It has been demonstrated that FTIR-PAS can be a useful experimental tool for the characterization of coffee.

Bilateral ligation of the anterior trunk of the internal iliac artery in uterine atony secondary to uterine inversion: case report.

Postpartum hemorrhage is one of the leading causes of maternal mortality worldwide. Uterine atony is the main cause, representing up to 90% of cases, and is a risk factor for uterine inversion. Morbidity and mortality occur in 41% of uterine inversion cases, including massive obstetric hemorrhage. Massive obstetric hemorrhage is a medical emergency that puts life and reproductive function at risk, and therefore, its treatment must be timely and immediate. If there is no favorable response with the initial measures, surgical intervention proceeds. When choosing the surgical procedure, priority should be given to the technique with the easiest access and which is the least invasive, the safest, and in which the surgeon has more experience. We present a case report with our technique of bilateral ligation of the anterior trunk of the hypogastric artery, after a uterine compression suture failed, with excellent results and preserved fertility in an adolescent patient. We describe the technique and the result. The response time of the uterus with normal tone was 5 minutes, and postligation bleeding was only 50 mL after the patient had bled 1200 mL without complications; thus, it is an adequate and cost-effective technique. The bilateral ligation of the anterior trunk of the hypogastric artery technique in the case of postpartum hemorrhage is an effective, safe, and fertility-preserving surgical procedure that constitutes an alternative to emergency obstetrical hysterectomy when other, less invasive methods have failed.

Spin excitations of individual magnetic dopants in an ionic thin film.

Individual magnetic transition metal dopants in a solid host usually exhibit relatively small spin excitation energies of a few meV. Using scanning tunneling microscopy and inelastic electron tunneling spectroscopy (IETS) techniques, we have observed a high spin excitation energy around 36 meV for an individual Co substitutional dopant in ultrathin NaCl films. In contrast, the Cr dopant in the NaCl film shows much lower spin excitation energy around 2.5 meV. Electronic multiplet calculations combined with first-principles calculations confirm the spin excitation induced IETS, and quantitatively reveal the out-of-plane magnetic anisotropies for both Co and Cr. They also allow reproducing the experimentally observed redshift in the spin excitations of Co dimers and ascribe it to a charge and geometry redistribution.

Botfly Parasitism on Two Primates of the Cebidae Family in Peru.

Botflies (Diptera:Oestridae) are a diverse group of insect parasites that affect various vertebrate species. There are previous reports of myiasis affecting wild primates in Central and South America; however, information about botfly parasitism in Peruvian primates is scarce. We present data from two Cebidae primate specimens: a rescued large-headed capuchin monkey (Sapajus macrocephalus) housed at Taricaya Rescue Center, in Tambopata, Peru, and a free-ranging white-fronted capuchin monkey (Cebus albifrons aequatorialis) inhabiting Cerros de Amotape National Park. The first specimen had a larva identified as Dermatobia hominis, whereas Cuterebra baeri larvae infested the second. In both cases we initially identified the parasite species through their morphologic features before confirming the identification with genetic analysis through the cytochrome C oxidase subunit 1 mitochondrial gene sequencing of the larvae. Further field studies on the primate-parasite dynamics are needed to understand the impact of botfly myiasis on primate populations.

Express improvement of acute stroke care accessibility in large regions using a centralized telestroke network.

Introduction: Acute ischemic stroke therapy has improved in recent decades, decreasing the rates of disability and death among stroke patients. Unfortunately, all health care systems have geographical disparities in infrastructure for stroke patients. A centralized telestroke network might be a low-cost strategy to reduce differences in terms of geographical barriers, equitable access, and quality monitoring across different hospitals. Aims: We aimed to quantify changes in stroke patients' geographic access to specialized evaluation by neurologists and to intravenous acute stroke reperfusion treatments following the rapid implementation of a centralized telestroke network in the large region of Andalusia (8.5 million inhabitants). Methods: We conducted an observational study using spatial and analytical methods to examine how a centralized telestroke network influences the quality and accessibility of stroke care for a large region. Results: In the pre-implementation period, 5,005,477 (59.72% of the Andalusian population) had access to specialized stroke care in less than 30 min. After the 5-month process of implementing the telestroke network, 7,832,988 (93.5%) inhabitants had an access time of less than 30 min, bridging the gap in acute stroke care in rural hospitals. Conclusions: A centralized telestroke network may be an efficient tool to reduce the differences in stroke care access and quality monitoring across different hospitals, especially in large regions with low population density.

Novel Roles of the Nipah Virus Attachment Glycoprotein and Its Mobility in Early and Late Membrane Fusion Steps.

The Paramyxoviridae family comprises important pathogens that include measles (MeV), mumps, parainfluenza, and the emerging deadly zoonotic Nipah virus (NiV) and Hendra virus (HeV). Paramyxoviral entry into cells requires viral-cell membrane fusion, and formation of paramyxoviral pathognomonic syncytia requires cell-cell membrane fusion. Both events are coordinated by intricate interactions between the tetrameric attachment (G/H/HN) and trimeric fusion (F) glycoproteins. We report that receptor binding induces conformational changes in NiV G that expose its stalk domain, which triggers F through a cascade from prefusion to prehairpin intermediate (PHI) to postfusion conformations, executing membrane fusion. To decipher how the NiV G stalk may trigger F, we introduced cysteines along the G stalk to increase tetrameric strength and restrict stalk mobility. While most point mutants displayed near-wild-type levels of cell surface expression and receptor binding, most yielded increased NiV G oligomeric strength, and showed remarkably strong defects in syncytium formation. Furthermore, most of these mutants displayed stronger F/G interactions and significant defects in their ability to trigger F, indicating that NiV G stalk mobility is key to proper F triggering via moderate G/F interactions. Also remarkably, a mutant capable of triggering F and of fusion pore formation yielded little syncytium formation, implicating G or G/F interactions in a late step occurring post fusion pore formation, such as the extensive fusion pore expansion required for syncytium formation. This study uncovers novel mechanisms by which the G stalk and its oligomerization/mobility affect G/F interactions, the triggering of F, and a late fusion pore expansion step-exciting novel findings for paramyxoviral attachment glycoproteins. IMPORTANCE The important Paramyxoviridae family includes measles, mumps, human parainfluenza, and the emerging deadly zoonotic Nipah virus (NiV) and Hendra virus (HeV). The deadly emerging NiV can cause neurologic and respiratory symptoms in humans with a >60% mortality rate. NiV has two surface proteins, the receptor binding protein (G) and fusion (F) glycoproteins. They mediate the required membrane fusion during viral entry into host cells and during syncytium formation, a hallmark of paramyxoviral and NiV infections. We previously discovered that the G stalk domain is important for triggering F (via largely unknown mechanisms) to induce membrane fusion. Here, we uncovered new roles and mechanisms by which the G stalk and its mobility modulate the triggering of F and also unexpectedly affect a very late step in membrane fusion, namely fusion pore expansion. Importantly, these novel findings may extend to other paramyxoviruses, offering new potential targets for therapeutic interventions.

In vitro-generated interspecific recombinants between bovine herpesviruses 1 and 5 show attenuated replication characteristics and establish latency in the natural host.

BACKGROUND: Interspecific recombinant viruses R1ΔgC and R2ΔgI were isolated after in vitro co-infection with BoHV-1 and BoHV-5, two closely related alphaherpesviruses that infect cattle. The genetic characterization of R1ΔgC and R2ΔgI showed that they are composed of different sections of the parental genomes. The aim of this study was the characterization of the in vivo behavior of these recombinants in the natural host. RESULTS: Four groups of four 3-month-old calves of both genders were intranasally inoculated with either the recombinant or parental viruses. A control group of two animals was also included. Viral excretion and clinical signs were monitored after infection. Histopathological examination of the central nervous system (CNS) was performed and the establishment of latency in trigeminal ganglia was analyzed by PCR. The humoral response was also evaluated using ELISA tests. Three out of four animals from the BoHV-5 infected group excreted virus for 4-10 days. Two calves shed R1ΔgC virus for one day. In R2ΔgI and BoHV-1.2ΔgCΔgI groups, infectious virus was isolated only after two or three blind passages. None of the infected animals developed neurological signs, although those infected with BoHV-5 showed histopathological evidence of viral infection. Latent viral DNA was detected in at least one calf from each infected group. Serum and/or mucosal antibodies were detected in all groups. CONCLUSION: Both BoHV-1/-5 recombinants and the BoHV-1 parental strain are attenuated in calves, although they are able to replicate in animals at low rates and to establish latent infections.