bluuebunny/crossref_metadata_2025 huggingface dataset:
Does the Length of Dental Implants Inserted in Areas of Inferior Alveolar Nerve Lateralization Interfere on Mandibular Resistance to Fracture?
Authors: Brackmann Mariana Schaffer , Padovan Luis Eduardo Marques , Marcantonio Junior Elcio , Klüppel Leandro Eduardo
Published: March 2019

The aim of this study was to compare, in vitro, the mechanical resistance to vertical displacement of the mandible after osteotomy for lateralization of the inferior alveolar nerve and installation of dental implants. One hundred eighty polyurethane mandibles were equally divided into 6 groups: G1—intact hemi-mandibles (control group), G2—hemi-mandibles after osteotomy for lateralization of the inferior alveolar nerve, G3—hemi-mandibles with installation of 3 bicortical dental implants (3.75 × 13 mm), G4—hemi-mandibles with installation of 3 dental implants that did not reach the basal cortical bone (3.75 × 11 mm), G5—hemi-mandibles after osteotomy for lateralization of the inferior alveolar nerve and installation of 3 bicortical dental implants (3.75 × 13 mm) and G6—hemi-mandibles after osteotomy for lateralization of the inferior alveolar nerve and installation of 3 dental implants that did not reach the basal cortical bone (3.75 × 11 mm). The specimens were subjected to linear loading tests. The highest mean value of maximum load was found in G1 (412.36N ± 11.99), followed by G2 (396.87N ± 23.94), G3 (319.63N ± 57.28), G4 (303.34N ± 18.25), G5 (231.75N ± 63.64) and G6 (228.13N ± 20.75). Based on this data, it can be concluded that the bicorticalization (or not) of the implants was not a statistically significant risk factor for the vertical displacement of polyurethane hemi-mandibles.
Cerebral Revascularization Accelerates the Angiographic Staging Progression of the Operated Hemisphere in a Pediatric Patient With Moyamoya Disease
Authors: Yu Le-Bao , Ma Yong-Gang , Zhang Dong
Published: March 2019

Background and Objective:

Angiographic staging progression in the operated hemisphere of patient with moyamoya disease (MMD) is a common phenomenon that neurosurgeons may encounter. However, few studies have been carried out to demonstrate the correlation between the operation and angiographic staging progression. This study aimed to reveal whether cerebral revascularization would affect the stage progression in patient with MMD.

Methods:

A total of 20 pediatric patients with bilateral MMD were included in this study. All enrolled patients were at the similar Suzuki angiographic staging on bilateral hemispheres and cerebral revascularization was performed in unilateral hemisphere. Angiographic examination was performed in the first year after the operation to evaluate the progression of the lesions.

Results:

Cerebral revascularizations including direct bypass or encephaloduroarteriosynangiosis were performed in 20 hemispheres. During the follow-up, the incidence of stage progression in the operated hemisphere was significantly higher than in the contralateral side (80.0% versus 20.0%, respectively; P = 0.036) and the interval of disease progression was significantly shorter in the operated side than in the contralateral side (mean interval time, 7.3 versus 10 months). Earlier Suzuki stage on hemisphere represented faster pace of stage progression compared with server Suzuki stage (OR = −0.612, P = 0.004), while neoformative collaterals had not significant correlation with the progression pace. The leptomeningeal collaterals from the posterior circulation decreased in almost all operated hemisphere, while gradually increasing in the contralateral hemisphere. Symptoms were improved in all patients after operation.

Conclusion:

Cerebral revascularization would significantly accelerate the angiographic staging progression on the treated hemisphere, while it would not cause the deterioration of the patient's condition. The progression pace was associated with Suzuki stage.
Craniofacial Skills: A 2-Site Validation of Assessments to Aid Plastic Surgery Resident Milestone Achievement in Technical Skills and Instrument Knowledge
Authors: Grunzweig Katherine A. , Son Ji , Kumar Anand R.
Published: March 2019

Background:

Plastic surgery evaluates residents on milestones. This study defines a model of education including pre and post-test assessments paired with didactics intended for evaluating residents in the unique technical skills of craniofacial surgery.

Methods:

At the first institution, instrument identification, and time/accuracy of burr hole placement, craniotomy, and plating on Saw Bones Craniofacial Models were tested before and after a 7.5-hour craniofacial orthognathic surgery workshop. At the second institution, this was refined, removing plating, eliminating assessment of timing, and shortening didactics to standard osteotomies, instrument names, and common surgical approaches. The study population consisted of junior, mid-level, and senior residents on 2 different University craniofacial services.

Results:

Participant performance was analyzed by level of training: junior, midlevel and senior resident. In the first iteration, resident times improved significantly for all 4 tasks (P = 0.008, 0.035, 0.035, 0.016). Resident accuracy improved significantly for instrument naming (P = 0.003). Except for instrument naming, resident year did not impact improvement (timing: P = 0.062, 0.310, 0.125, 0.334; accuracy: P = 0.029, 0.664, 0.717, 0.306). In the second iteration, resident accuracy improved for all tasks (instrument naming P = 0.00002, burr holes P = 0.0031, craniotomy P = 0.08). There was no difference in rate of improvement between resident cohorts.

Conclusion:

The task-based assessment with resident education on basic craniofacial surgery skills, standard osteotomies, and instrument names directed resident learning and assessed resident knowledge. With the removal of time as a metric, all tasks improved in accuracy. The craniofacial skills task-assessment successfully evaluated milestone attainment in a reproducible model.
Craniofacial Anthropometric Profile of East Asians
Authors: Raveendran Maria
Published: March 2019

Facial anthropometric data has significant ethnic variation. East Asia, comprised of fourteen countries, represents a significant proportion of the global population. This systematic review presents the facial anthropometric data collected from these countries. The systematic review was conducted in accordance with PRISMA guidelines. An electronic search of the MEDLINE database returned 3054 articles. Twenty articles were considered eligible for inclusion. Nine studies were conducted in China, 1 in Indonesia, 2 in Japan,3 in Korea, 4 in Malaysia, and 1 was a multicentre study conducted in China, Japan, Thailand, and Vietnam. Qualitative and quantitative parameters were extracted from the20 studies. No data was found for the other East Asian countries. There is a paucity of facial anthropometric data for East Asian countries despite their high burden of craniofacial anomalies and a strong demand for cosmetic facial surgery, both of which would benefit from the collection of robust craniofacial norms. It is in the interest of both the craniofacial surgeon and the East Asian patient to collect baseline facial anthropometric data for this population.
Gender Confirmation Surgery: Moving Forward
Authors: Schechter Loren S. , Cohen Mimis
Published: March 2019

Facial surgery can help facilitate an individual's social transition and alleviate gender dysphoria. As such, surgical requests for feminizing and masculinizing procedures continue to increase. Surgical management requires knowledge of anatomy and anatomic differences as well as an understanding of social challenges faced by transgender and gender diverse individuals. Here, the authors provide a brief overview of gender confirmation surgery specific to the head and neck and craniofacial skeleton. In addition, the authors explore barriers to accessing healthcare for transgender and gender diverse individuals throughout the world.
Pros and Cons of the Transconjunctival Retroseptal Approach to the Isolated Orbital Floor Fracture
Authors: Riyadh Safaa , Abdulrazaq Saif Saadedeen , Mohammad Yuksel Yashar
Published: March 2019

To get access into the orbital floor 3 paths are commonly used which are transconjunctival, subciliary and subtarsal approaches. Each one of these approaches has its advantages and disadvantages. The study assessed the outcomes of the transconjunctival retroseptal approach, which reflects our experience in this type of surgery. Along 8 years, 26 patients received in the emergency room diagnosed with pure isolated orbital floor fractures, all of them admitted to the maxillofacial surgery department and approached by transconjunctival incision without lateral canthotomy. Three types of complications occurred: laceration of the lower eyelid, injury to the lacrimal system and entropion. All of these complications were managed accordingly with no long-term deficit. Although the transconjunctival approach without lateral canthotomy is limited to a certain degree, it has the advantages of hidden scar, easy, and short time to achieve.
Histologic and Radiographic Characteristics of Bone Filler Under Bisphosphonates
Authors: Yifat Manor , Hila Elias , Avraham Hirshberg , Inchingolo Francesco , Mortellaro Carmen , Peleg Oren , Mijiritsky Eithan
Published: March 2019

Background:

Dental implants and bone augmentation are well-established procedures used for oral rehabilitation. There is an increasing interest in biological mediators used topically for prevention of bone resorption maybe enhancement of osseointegration of dental implants. The purpose of the manuscript is to describe preliminarily the effect of bisphosphonates on the ossification pattern of bone grafts in a rat model.

Material and Methods:

Twenty Wistar-derived male rats were divided into 2 groups study and control. Bone substitute was added to mandibular defects and was covered by a resorbable collagen membrane. In the study group, the membrane was soaked with bisphosphonates suspension. In the control group, the membrane was soaked with saline solution. Radiographic and histomorphometric evaluation were performed.

Results:

Radiographically, it was found that bone density was significantly higher in the study group. Histomorphometric analysis revealed a trend of higher bone volume fraction along with reduced bone substitute volume fraction in the study group, and increased number of osteoclasts and blood vessels in the control group.

Conclusions:

Within the limitations of our study it was found that there is a trend of increasing bone quantity and radiographic bone density by application of bisphosphonates.
Proposal of Standardization of Closure Techniques After Endoscopic Pituitary and Skull Base Surgery Based on Postoperative Cerebrospinal Fluid Leak Risk Classification
Authors: Ruggeri Andrea G. , Cappelletti Martina , Giovannetti Filippo , Priore Paolo , Pichierri Angelo , Delfini Roberto
Published: March 2019

Postoperative cerebrospinal fluid (CSF) leak still represents the main limitation of endonasal endoscopic surgery. The aim of the study is to classify the risk of postoperative leak and to propose a decision-making protocol to be applied in the preoperative phase based on radiological data and on intraoperative findings to obtain the best closure.

One hundred fifty-two patients were treated in our institution; these patients were divided into 2 groups because from January 2013 the closure technique was standardized adopting a preoperative decision-making protocol. The Postoperative CSF leak Risk Classification (PCRC) was estimated taking into account the size of the lesion, the extent of the osteodural defect, and the presence of intraoperative CSF leak (iCSF-L). The closure techniques were classified into 3 types according to PCRC estimation (A, B, and C).

The incidence of the use of a nasoseptal flap is significantly increased in the second group 80.3% versus 19.8% of the first group and the difference was statistically significant P < 0.0001. The incidence of postoperative CSF leak (pCSF-L) in the first group was 9.3%. The incidence of postoperative pCSF-L in the second group was 1.5%. An analysis of the pCSF-L rate in the 2 groups showed a statistically significant difference P = 0.04.

The type of closure programmed was effective in almost all patients, allowing to avoid the possibility of a CSF leak. Our protocol showed a significant total reduction in the incidence of CSF leak, but especially in that subgroup of patients where a leak is usually unexpected.
Four-factor prothrombin complex concentrate is associated with improved survival in trauma-related hemorrhage: A nationwide propensity-matched analysis
Authors: Zeeshan Muhammad , Hamidi Mohammad , Feinstein Ara J. , Gries Lynn , Jehan Faisal , Sakran Joseph , Northcutt Ashley , O'Keeffe Terence , Kulvatunyou Narong , Joseph Bellal
Published: March 2019

INTRODUCTION

Post-traumatic hemorrhage is the most common preventable cause of death in trauma. Numerous small single-center studies have shown the superiority of four-factor prothrombin complex concentrate (4-PCC) along with fresh frozen plasma (FFP) over FFP alone in resuscitation of trauma patients. The aim of our study was to evaluate outcomes of severely injured trauma patients who received 4-PCC + FFP compared to FPP alone.

METHODS

Two-year (2015–2016) analysis of the American College of Surgeons-Trauma Quality Improvement Program database. All adult (age ≥18 years) trauma patients who received 4-PCC + FFP or FFP alone were included. We excluded patients who were on preinjury anticoagulants. Patients were stratified into two groups: 4-PCC + FFP versus FFP alone and were matched in a 1:1 ratio using propensity score matching for demographics, vitals, injury parameters, comorbidities, and level of trauma centers. Outcome measures were packed red blood cells, plasma and platelets transfused, complications, and mortality.

RESULTS

A total of 468 patients (4-PCC + FFP, 234; FFP alone, 234) were matched. Mean age was 50 ± 21 years; 70% were males; median injury severity score was 27 [20–36], and 86% had blunt injuries. Four-PCC + FFP was associated with a decreased requirement for packed red blood cells (6 units vs. 10 units; p = 0.02) and FFP (3 units vs. 6 units; p = 0.01) transfusion compared to FFP alone. Patients who received 4-PCC + FFP had a lower mortality (17.5% vs. 27.7%, p = 0.01) and lower rates of acute respiratory distress syndrome (1.3% vs. 4.7%, p = 0.04) and acute kidney injury (2.1% vs. 7.3%, p = 0.01). There was no difference in the rates of deep venous thrombosis (p = 0.11) and pulmonary embolism (p = 0.33), adverse discharge disposition (p = 0.21), and platelets transfusion (p = 0.72) between the two groups.

CONCLUSIONS

Our study demonstrates that the use of 4-PCC as an adjunct to FFP is associated with improved survival and reduction in transfusion requirements compared to FFP alone in resuscitation of severely injured trauma patients. Further studies are required to evaluate the role of addition of PCC to the massive transfusion protocol.

LEVEL OF EVIDENCE

Therapeutic studies, level III.
Exposure of von Willebrand Factor on Isolated Hepatocytes Promotes Tethering of Platelets to the Cell Surface
Authors: Gustafson Elisabet , Hamad Osama A. , Deckmyn Hans , Barbu Andreea , Ekdahl Kristina N. , Nilsson Bo
Published: March 2019

Background.

Hepatocyte transplantation (Hctx) is a potentially attractive method for the treatment of acute liver failure and liver-based metabolic disorders. Unfortunately, the procedure is hampered by the instant blood-mediated inflammatory reaction (IBMIR), a thromboinflammatory response elicited by the vascular innate immune system, causing activation of the coagulation and complement systems and clearance of transplanted cells. Observations have also revealed platelets adhered to the surface of the hepatocytes (Hc). To establish Hctx as a clinical treatment, all factors that trigger IBMIR need to be identified and controlled. This work explores the expression of von Willebrand factor (VWF) on isolated Hc resulting in tethering of platelets.

Methods.

VWF on Hc was studied by flow cytometry, confocal microscopy, immunoblot, and real-time polymerase chain reaction. Interaction between Hc and platelets was studied in a Chandler loop model. Adhesion of platelets to the hepatocyte surface was demonstrated by flow cytometry and confocal microscopy.

Results.

Isolated Hc constitutively express VWF on their cell surface and mRNA for VWF was found in the cells. Hc and platelets, independently of coagulation formed complexes, were shown by antibody blocking studies to be dependent on hepatocyte-associated VWF and platelet-bound glycoprotein Ibα.

Conclusions.

VWF on isolated Hc causes, in contact with blood, adhesion of platelets, which thereby forms an ideal surface for coagulation. This phenomenon needs to be considered in hepatocyte-based reconstitution therapy and possibly even in other settings of cell transplantation.
A Multicenter Application of the 2018 Banff Classification for BK Polyomavirus-associated Nephropathy in Renal Transplantation
Authors: Bouatou Yassine , Nguyen Tri Q. , Roelofs Joris J.T.H. , Bemelman Frederike J. , Michielsen Laura , Goldschmeding Roel , Kers Jesper , Florquin Sandrine
Published: March 2019

Background.

With current immunosuppressive regimens, BK polyomavirus-associated nephropathy (BKPyVAN) is still a matter of concern. Stratification of patients at risk for allograft loss is of uttermost importance to guide treatment choice and assess prognosis. In 2018, the Banff working group proposed a classification scheme for the prognosis of BKPyVAN, but external application on independent cohorts is yet to be performed. We investigated how the 2018 Banff classification would perform in a multicenter cohort comprising 50 cases of biopsy-proven BKPyVAN compared to previously published classification systems.

Methods.

We analyzed consecutive BKPyVAN cases from two Dutch university hospitals between 2002 and 2013, retrieved clinical data, and scored all biopsies according to the Banff 2018 classification, and as a comparison, 4 previously proposed BKPyVAN classification systems. We used estimated glomerular filtration rate trajectories and death-censored graft survival as primary endpoints.

Results.

The 2018 Banff classification did not associate with estimated glomerular filtration rate decline or graft failure and performed only slightly better than the 4 previously proposed classifiers. Anti-human leukocyte antigen donor-specific antibodies (DSAs), especially in combination with ongoing biopsy-proven BKPyVAN on follow-up, did correlate with graft function and survival. Patients who were DSA+/BKPyVAN+ on follow-up had more inflammation at the baseline biopsy, which by itself was not associated with graft outcomes.

Conclusions.

Neither the 2018 Banff BKPyVAN classification nor previously published stratification systems could be applied to our multicenter patient cohort. Our data suggest that there might be a prognostic value for follow-up biopsies and DSA measurements to improve risk stratification after BKPyVAN, although prospective multicenter efforts with protocol measurements are needed to confirm this.
Differences in Awareness of Disease Between Young-onset and Late-onset Dementia
Authors: Baptista Maria A.T. , Santos Raquel L. , Kimura Nathália , Marinho Valeska , Simões José P. , Laks Jerson , Johannenssen Aud , Barca Maria L. , Engedal Knut , Dourado Marcia C.N.
Published: March 2019

Introduction:

Awareness of disease is the ability to acknowledge changes caused by deficits related to the disease process. We aimed to investigate whether there are differences in awareness of disease between young-onset dementia (YOD) and late-onset dementia (LOD) and examined how awareness interacts with cognitive and clinical variables.

Materials and Methods:

Using a cross-sectional design, 49 people with YOD and 83 with LOD and their caregivers were included. We assessed awareness of disease, cognition, functionality, stage of dementia, mood, neuropsychiatric symptoms, and caregivers’ quality of life (QoL) and burden.

Results:

We found that people with YOD were more aware of the disease than people with LOD (P<0.005). Multivariate linear regression revealed that higher impairment in functional level was associated with unawareness in both groups (YOD=P<0.001; LOD=P<0.001). In the YOD group, preserved awareness was related to worse self-reported QoL (P<0.05), whereas, in LOD, deficits in awareness were related to caregivers’ worst perceptions about people with dementia QoL (P<0.001).

Conclusions:

The findings highlight the distinct nature of awareness between YOD and LOD. The YOD group had higher levels of disease awareness compared with the LOD group, even though the first group had a greater impairment in functionality.
Neurotoxicity associated with cancer immunotherapy: immune checkpoint inhibitors and chimeric antigen receptor T-cell therapy
Authors: Perrinjaquet Claire , Desbaillets Nicolas , Hottinger Andreas F.
Published: March 2019

Purpose of review

Immune checkpoint inhibitors (ICPI) and chimeric antigen receptor T cells (CAR-T) represent novel therapies recently approved to treat a number of human cancers. As both approaches modulate the immune system, they can generate a number of immune-related adverse events (irAEs), including a large spectrum of novel neurological toxicities. These are of special interest given their potential severity and risk of compromising further oncologic treatment. We aim to provide a comprehensive review of the literature and discuss their optimal management.

Recent findings

In contrast to irAEs involving other organs, neurological complications of ICPI are uncommon, may present throughout the course of treatment and involve the peripheral and central nervous system, including polyneuropathy, myositis, myasthenia gravis, demyelinating polyradiculopathy, myelitis, encephalitis and others. If started early, ICPI-related neurologic irAEs are usually responsive to steroids. In contrast, as many as 40% of patients undergoing CAR-T therapy will develop neurologic complications in the form of a cytokine-release-associated encephalopathy. It includes delirium, aphasia, tremor/myoclonus, seizure and seizure-like activity.

irAEs associated with CAR-T and ICPI therapy constitute new entities. Early identification and treatment are essential to optimize the functional outcome and further oncologic management of the patient.
Neuromyelitis optica spectrum disorders: still evolving and broadening
Authors: Fujihara Kazuo
Published: March 2019

Purpose of review

The diagnostic criteria of neuromyelitis optica spectrum disorders (NMOSD) has been revised in the past 20 years and pathological and therapeutic data have been accumulated. This review provides an overview of evolution and broadening of the concept of NMOSD.

Recent findings

NMOSD encompassing brain syndrome as well as optic neuritis and acute myelitis is now classified into aquaporine-4 (AQP)-antibody-seropositive and aquaporine-4 (AQP)-antibody-seronegative diseases, detecting more patients earlier than before. Seronegative NMOSD includes cases of myelin oligodendrocyte glycoprotein (MOG)-antibody-seropositive disease with its unique clinical spectrum somewhat different from AQP4-antibody-seropositive NMOSD. Pathologically, NMOSD includes AQP4-antibody-seropositive autoimmune astrocytopathic disease and MOG-antibody-seropositive inflammatory demyelinating disease. Double seronegative group needs further research. Therapeutic options of NMOSD has taken shape and first-ever clinical trials of monoclonal antibodies have been done. In retrospect, relapsing NMO in the studies preceding the discovery of AQP4-antibody had features of AQP4-antibody-seropositive NMO whereas monophasic NMO was similar to AQP4-antibody-seronegative/MOG-antibody-seropositive NMO.

The clinical, pathological and therapeutic concepts of NMOSD have evolved and broadened over the last two decades following the detection of AQP4 antibodies and MOG antibodies in the patients. Double seronegative NMOSD is a current research focus, but now we may need to reconsider how NMOSD should be defined.
A matter of background: DNA repair pathways as a possible cause for the sparse distribution of CRISPR-Cas systems in bacteria
Authors: Bernheim Aude , Bikard David , Touchon Marie , Rocha Eduardo P. C.
Published: March 2019

The absence of CRISPR-Cas systems in more than half of the sequenced bacterial genomes is intriguing, because their role in adaptive immunity and their frequent transfer between species should have made them almost ubiquitous, as is the case in Archaea. Here, we investigate the possibility that the success of CRISPR-Cas acquisition by horizontal gene transfer is affected by the interactions of these systems with the host genetic background and especially with components of double-strand break repair systems (DSB-RS). We first described the distribution of systems specialized in the repair of double-strand breaks in Bacteria: homologous recombination and non-homologous end joining. This allowed us to show that such systems are more often positively or negatively correlated with the frequency of CRISPR-Cas systems than random genes of similar frequency. The detailed analysis of these co-occurrence patterns shows that our method identifies previously known cases of mechanistic interactions between these systems. It also reveals other positive and negative patterns of co-occurrence between DSB-RS and CRISPR-Cas systems. Notably, it shows that the patterns of distribution of CRISPR-Cas systems in Proteobacteria are strongly dependent on the epistatic groups including RecBCD and AddAB. Our results suggest that the genetic background plays an important role in the success of adaptive immunity in different bacterial clades and provide insights to guide further experimental research on the interactions between CRISPR-Cas and DSB-RS.

This article is part of a discussion meeting issue ‘The ecology and evolution of prokaryotic CRISPR-Cas adaptive immune systems’.
Diversified local CRISPR-Cas immunity to viruses ofSulfolobus islandicus
Authors: Pauly Matthew D. , Bautista Maria A. , Black Jesse A. , Whitaker Rachel J.
Published: March 2019

The population diversity and structure of CRISPR-Cas immunity provides key insights into virus–host interactions. Here, we examined two geographically and genetically distinct natural populations of the thermophilic crenarchaeonSulfolobus islandicusand their interactions withSulfolobusspindle-shaped viruses (SSVs) andS. islandicusrod-shaped viruses (SIRVs). We found that both virus families can be targeted with high population distributed immunity, whereby most immune strains target a virus using unique unshared CRISPR spacers. In Kamchatka, Russia, we observed high immunity to chronic SSVs that increases over time. In this context, we found that some SSVs had shortened genomes lacking genes that are highly targeted by theS. islandicuspopulation, indicating a potential mechanism of immune evasion. By contrast, in Yellowstone National Park, we found high inter- and intra-strain immune diversity targeting lytic SIRVs and low immunity to chronic SSVs. In this population, we observed evidence of SIRVs evolving immunity through mutations concentrated in the first five bases of protospacers. These results indicate that diversity and structure of antiviral CRISPR-Cas immunity for a single microbial species can differ by both the population and virus type, and suggest that different virus families use different mechanisms to evade CRISPR-Cas immunity.

This article is part of a discussion meeting issue ‘The ecology and evolution of prokaryotic CRISPR-Cas adaptive immune systems’.
The effect of bacterial mutation rate on the evolution of CRISPR-Cas adaptive immunity
Authors: Chevallereau Anne , Meaden Sean , van Houte Stineke , Westra Edze R. , Rollie Clare
Published: March 2019

CRISPR-Cas immune systems are present in around half of bacterial genomes. Given the specificity and adaptability of this immune mechanism, it is perhaps surprising that they are not more widespread. Recent insights into the requirement for specific host factors for the function of some CRISPR-Cas subtypes, as well as the negative epistasis between CRISPR-Cas and other host genes, have shed light on potential reasons for the partial distribution of this immune strategy in bacteria. In this study, we examined how mutations in the bacterial mismatch repair system, which are frequently observed in natural and clinical isolates and cause elevated host mutation rates, influence the evolution of CRISPR-Cas–mediated immunity. We found that hosts with a high mutation rate very rarely evolved CRISPR-based immunity to phage compared to wild-type hosts. We explored the reason for this effect and found that the higher frequency at which surface mutants pre-exist in the mutator host background causes them to rapidly become the dominant phenotype under phage infection. These findings suggest that natural variation in bacterial mutation rates may, therefore, influence the distribution of CRISPR-Cas adaptive immune systems.

This article is part of a discussion meeting issue ‘The ecology and evolution of prokaryotic CRISPR-Cas adaptive immune systems’.
Cost and benefits of clustered regularly interspaced short palindromic repeats spacer acquisition
Authors: Bradde Serena , Mora Thierry , Walczak Aleksandra M.
Published: March 2019

Clustered regularly interspaced short palindromic repeats (CRISPR)-Cas-mediated immunity in bacteria allows bacterial populations to protect themselves against pathogens. However, it also exposes them to the dangers of auto-immunity by developing protection that targets its own genome. Using a simple model of the coupled dynamics of phage and bacterial populations, we explore how acquisition rates affect the probability of the bacterial colony going extinct. We find that the optimal strategy depends on the initial population sizes of both viruses and bacteria. Additionally, certain combinations of acquisition and dynamical rates and initial population sizes guarantee protection, owing to a dynamical balance between the evolving population sizes, without relying on acquisition of viral spacers. Outside this regime, the high cost of auto-immunity limits the acquisition rate. We discuss these optimal strategies that minimize the probability of the colony going extinct in terms of recent experiments.

This article is part of a discussion meeting issue ‘The ecology and evolution of prokaryotic CRISPR-Cas adaptive immune systems’.
Variability in the durability of CRISPR-Cas immunity
Authors: Chabas Hélène , Nicot Antoine , Meaden Sean , Westra Edze R. , Tremblay Denise M. , Pradier Léa , Lion Sébastien , Moineau Sylvain , Gandon Sylvain
Published: March 2019

The durability of host resistance is challenged by the ability of pathogens to escape the defence of their hosts. Understanding the variability in the durability of host resistance is of paramount importance for designing more effective control strategies against infectious diseases. Here, we study the durability of various clustered regularly interspaced short palindromic repeats-Cas (CRISPR-Cas) alleles of the bacteria
Streptococcus thermophilus
against lytic phages. We found substantial variability in durability among different resistant bacteria. Since the escape of the phage is driven by a mutation in the phage sequence targeted by CRISPR-Cas, we explored the fitness costs associated with these escape mutations. We found that, on average, escape mutations decrease the fitness of the phage. Yet, the magnitude of this fitness cost does not predict the durability of CRISPR-Cas immunity. We contend that this variability in the durability of resistance may be because of variations in phage mutation rate or in the proportion of lethal mutations across the phage genome. These results have important implications on the coevolutionary dynamics between bacteria and phages and for the optimal deployment of resistance strategies against pathogens and pests. Understanding the durability of CRISPR-Cas immunity may also help develop more effective gene-drive strategies based on CRISPR-Cas9 technology.

This article is part of a discussion meeting issue ‘The ecology and evolution of prokaryotic CRISPR-Cas adaptive immune systems’.
Heparan sulfates are critical regulators of the inhibitory megakaryocyte-platelet receptor G6b-B
Authors: Vögtle Timo , Sharma Sumana , Mori Jun , Nagy Zoltan , Semeniak Daniela , Geer Mitchell J. , Smith Christopher W. , Lane Jordan , Pollack Scott , Lassila Riitta , Jouppila Annukka , Barr Alastair J. , Ogg Derek J. , Howard Tina D. , McMiken Helen J. , Warwicker Juli , Geh Catherine , Rowlinson Rachel , Mark Abbott W. , Schulze Harald , Wright Gavin J. , Mazharian Alexandra , Fütterer Klaus , Rajesh Sundaresan , Douglas Michael R. , Senis Yotis A.
Published: March 2019

The immunoreceptor tyrosine-based inhibition motif (ITIM)-containing receptor G6b-B is critical for platelet production and activation, loss of which results in severe macrothrombocytopenia and aberrant platelet function in mice and humans. Using a combination of immunohistochemistry, affinity chromatography and proteomics, we identified the extracellular matrix heparan sulfate (HS) proteoglycan perlecan as a G6b-B binding partner. Subsequentin vitrobiochemical studies and a cell-based genetic screen demonstrated that the interaction is specifically mediated by the HS chains of perlecan. Biophysical analysis revealed that heparin forms a high-affinity complex with G6b-B and mediates dimerization. Using platelets from humans and genetically-modified mice, we demonstrate that binding of G6b-B to HS and multivalent heparin inhibits platelet and megakaryocyte function by inducing downstream signaling via the tyrosine phosphatases Shp1 and Shp2. Our findings provide novel insights into how G6b-B is regulated and contribute to our understanding of the interaction of megakaryocytes and platelets with glycans.
Linalool acts as a fast and reversible anesthetic inHydra
Authors: Goel Tapan , Wang Rui , Martin Sara , Lanphear Elizabeth , Collins Eva-Maria S.
Published: March 2019

The ability to make transgenicHydralines has opened the door for quantitativein vivostudies ofHydraregeneration and physiology. These studies commonly include excision, grafting and transplantation experiments along with high-resolution imaging of live animals, which can be challenging due to the animal’s response to touch and light stimuli. While various anesthetics have been used inHydrastudies over the years, they tend to be toxic over the course of a few hours or their long-term effects on animal health have not been studied. Here we show that the monoterpenoid linalool is a useful anesthetic forHydra. Linalool is easy to use, non-toxic, fast acting, and reversible. It has no detectable long-term effects on cell viability or cell proliferation. We demonstrate that the same animal can be immobilized in linalool multiple times at intervals of several hours for repeated imaging over 2-3 days. This uniquely allows forin vivoimaging of dynamic processes such as head regeneration. We further directly compare linalool to currently used anesthetics and show its superior performance. Because linalool, which is frequently utilized in perfumes and cosmetic products, is also non-hazardous to humans, it will be a useful tool forHydraresearch in both research and teaching contexts.
Molecular dissection of the structural and nonstructural proteins of spanish-1918 Influenza, pandemic-2009, and bird flu viruses
Authors: Mahardika Gusti Ngurah , Suartha Nyoman , Kencana Gusti Ayu Yuniati , Suardana Ida Bagus Kade , Budayanti Nyoman Sri
Published: March 2019

The potential emergence of deadly pandemic influenza viruses is unpredictable and most have emerged with no forewarning. The distinct epidemiological and pathological patterns of the Spanish (H1N1), pandemic-2009 (H1N1), and avian influenza (H5N1), known as bird flu, viruses may allow us to develop a ‘template’ for possible emergence of devastating pandemic strains. Here, we provide a detailed molecular dissection of the structural and nonstructural proteins of this triad of viruses. GenBank data for three representative strains were analyzed to determine the polymorphic amino acids, genetic distances, and isoelectric points, hydrophobicity plot, and protein modeling of various proteins. We propose that the most devastating pandemic strains may have full-length PB1-F2 protein with unique residues, highly cleavable HA, and a basic NS1. Any newly emerging strain should be compared with these three strains, so that resources can be directed appropriately.
A generic multivariate framework for the integration of microbiome longitudinal studies with other data types
Authors: Bodein Antoine , Chapleur Olivier , Droit Arnaud , Lê Cao Kim-Anh
Published: March 2019

Simultaneous profiling of biospecimens using different technological platforms enables the study of many data types, encompassing microbial communities, omics and meta-omics as well as clinical or chemistry variables. Reduction in costs now enables longitudinal or time course studies on the same biological material or system. The overall aim of such studies is to investigate relationships between these longitudinal measures in a holistic manner to further decipher the link between molecular mechanisms and microbial community structures, or host-microbiota interactions. However, analytical frameworks enabling an integrated analysis between microbial communities and other types of biological, clinical or phenotypic data are still in their infancy. The challenges include few time points that may be unevenly spaced and unmatched between different data types, a small number of unique individual biospecimens and high individual variability. Those challenges are further exacerbated by the inherent characteristics of microbial communities-derived data (e.g. sparsity, compositional).

We propose a generic data-driven framework to integrate different types of longitudinal data measured on the same biological specimens with microbial communities data, and select key temporal features with strong associations within the same sample group. The framework ranges from filtering and modelling, to integration using smoothing splines and multivariate dimension reduction methods to address some of the analytical challenges of microbiome-derived data. We illustrate our framework on different types of multi-omics case studies in bioreactor experiments as well as human studies.
Identification of blaGIM-1 in Acinetobacter variabilis isolated from the hospital environment in Tamil Nadu, India
Authors: Manohar Prasanth , Ragavi Murugavel , Augustine Ashby , MV Hrishikesh , Ramesh Nachimuthu
Published: March 2019

Background

Emergence of carbapenem resistance mechanisms among Gram-negative bacteria is a worrisome health problem. Here, we focused on to identify the presence of carbapenem-resistant bacteria among the samples collected from hospital environments in Tamil Nadu.

Methods

A total of 30 hospital environmental samples were collected between August 2017 and January 2018 from hospitals located in Chennai and Vellore such as lift switches, stair rails, switchboards, nursing desks, used nursing gloves, door handles, wheelchairs, touch screens, chairs and from pillars inside the hospitals.

Results and discussion

A total of 22 carbapenem-resistant Gram-negative bacteria were isolated that included Escherichia coli, Klebsiella sp., Enterobacter sp., Salmonella sp., Pseudomonas aeruginosa and Acinetobacter sp. Interestingly, blaGIM-1 was detected in Acinetobacter variabilis strain isolated in samples collected from hospitals. Unlike other studies, the identified GIM-1 was not plasmid encoded, and this is the first report for the presence of GIM-1 (German imipenemase) in India.

Conclusion

Extensive surveillance programs are necessary to trace the uncontrolled spread of carbapenem-resistance genes in order to reduce the rapid spread of resistance.
The developmental cycle ofDictyostelium discoideumensures curing of a mycobacterial infection at both cell-autonomous level and by collaborative exclusion
Authors: López-Jiménez Ana Teresa , Hagedorn Monica , Delincé Matthieu J. , McKinney John , Soldati Thierry
Published: March 2019

During its life cycle, the social amoebaDictyostelium discoideumalternates between a predatory amoeba and a facultative multicellular form. The single-celled amoeba is a well-established model system to study cell-autonomous mechanisms of phagocytosis and defence against intracellular bacterial pathogens, whereas the multicellular forms are arising as models to study the emergence of innate immune defence strategies. Importantly, during evolution, prokaryotes have also evolved their own strategies to resist predation. Considering these complex ecological relationships, we wondered whetherD. discoideumcells infected with intracellular pathogenic mycobacteria would be able to undergo their developmental cycle and what would be the fate of the infection. We show that the combination of cell-autonomous mechanisms and the organisation into a multicellular organism leads to the efficient multistep-curing of a mycobacteria-infected population, thereby ensuring germ-free spores and progeny. Specifically, using a microfluidic device to trap single infected cells, we revealed that in the first curing phase, individual cells rely on three mechanisms to release intracellular bacteria: exocytic release, ejection and lytic release. The second phase occurs at the collective level, when remaining infected cells are excluded from the forming cell aggregates.
Treatment of Murine Lupus with TIGIT-Ig
Authors: Liu Shuowu , Sun Lizhu , Wang Chuqi , Cui Yingshu , Ling Yuee , Li Tian , Lin Fangxing , Fu Wenyan , Ding Min , Zhang Shuyi , Lei Changhai , Hu Shi
Published: March 2019

The TIGIT (T cell immunoreceptor with Ig and ITIM domains) protein is a co-inhibitory receptor that has been reported to suppress autoreactive T and B cells to trigger immunological tolerance. We generated a new recombinant protein by connecting the extracellular domain of murine TIGIT to the Fc region of the rat immunoglobulin IgG2a. The fusion protein was then characterized. The results suggested that among mice with lupus that were treated with the TIGIT-Ig fusion protein, the onset of proteinuria was delayed, serum concentrations of autoantibodies, such as antinuclear antibodies, were reduced without a decrease in the total IgG concentrations, and the survival rate was significantly increased compared to those of the controls. In conclusion, TIGIT-Ig administration showed promising results for both the prevention and treatment of autoimmune diseases in mice. This indicates that treatment with recombinant human TIGIT-Ig shows promise as an effective way to treat human autoimmune diseases.
Phenotyping and molecular marker analysis of WH1105 and Kharchia 65 backcrosses and F4progenies for salinity tolerance
Authors: Varsha  , Yashveer Shikha , Singh Vikram , Pratap Swati
Published: March 2019

Soil salinity is a worldwide adverse environmental factor for crop productivity and quality in arid, semiarid and coastal areas. In India, approximately 8.5 million hectare of land area is affected by high salinity (EC ≥ 5 dS m−1). Development of salinity tolerant varieties through marker assisted breeding is most efficient and effective strategy for management of soil salinity. WH 1105 is widely cultivated wheat variety with many agronomically superior qualities but is affected by soil salinity. Two genes (Nax1andNax2) for salinity tolerance were introgressed from Kharchia 65 into the genetic background of WH 1105 through marker assisted backcross breeding. BC1F3, BC2F2and F4generations of the cross WH1105 x Kharchia 65 were evaluated for various morphological traits under initial salt stress condition. On the basis of phenotypic and genotypic variations 44 high yielding plants were selected from the cross. Out of 178 SSRs tested, 30 were found polymorphic for background selection of the foreground selected plants. Cluster tree analysis of parents and all the three generations showed that all the selected plants were inclined toward recurrent parent (WH 1105) indicating higher similarity with the recurrent parent. Four plants were selected as high grain yielding and salt tolerant. These plants could be further backcrossed with the recurrent parent to develop salt tolerant wheat lines.
Enriching hippocampal memory function in older adults through real-world exploration
Authors: Kolarik Branden S. , Stark Shauna M. , Rutledge Samantha M. , Stark Craig E.L.
Published: March 2019

Age-related structural and functional changes in the hippocampus can have a severe impact on hippocampally-dependent memory performance. Here we test the hypothesis that a real-world spatial exploration intervention will improve hippocampally-dependent memory performance in healthy older adults. We found that following our intervention, participants’ lure discrimination index (LDI) was significantly higher than it was at baseline, while traditional recognition scores remained relatively unchanged. These results point to the viability of a spatial exploration intervention for improving hippocampally-dependent memory in older adults.
Enriching hippocampal memory function in older adults through video games
Authors: Clemenson Gregory D. , Stark Shauna M. , Rutledge Samantha M. , Stark Craig E.L.
Published: March 2019

Healthy aging is accompanied by a steady cognitive decline with clear losses in memory. Animal studies have consistently demonstrated that simply modifying an animal’s living environment (known as environmental enrichment) can have a positive influence on age-related cognitive decline in the hippocampus. Previously, we showed that playing immersive 3D video games can improve hippocampal-based memory in young healthy adults, suggesting that the exploration of the large open worlds of modern-day video games may act as proxy for environmental enrichment in humans. Here, we replicated our previous video game study in older adults and showing that playing video games for 4 weeks can improve hippocampal-based memory in a population that is already experiencing age-related decline in this memory. Furthermore, we showed that the improvements last for up to 4 weeks past the intervention, highlighting the potential of video games as intervention for age-related cognitive decline.