Penetrating keratoplasty is a surgical intervention that despite the progress of surgical techniques and of postoperative treatment continues to have numerous complications. Many of them, such as graft rejection, significant astigmatism, cystoid macular edema, or cataract lead to important limitations of the visual function. Glaucoma is possibly the most dangerous complication following PK, leading to loss of the visual potential of the eye due to irreversible damage to the optic nerve. Identifying the risk factors permits an attentive follow-up and rapid treatment of the postoperative IOP rises. Maybe the most important is that preexisting glaucoma should be rightly diagnosed and controlled before PK, medically or, if necessary, surgically.Abbreviations: PK = penetrating keratoplasty, IOP = intraocular pressure, PAS = peripheral anterior synechiae, TM = trabecular meshwork, DM = Descemet membrane, GAT = Goldmann applanation tonometry, MMC = mitomycin C, CAI = carbonic anhydrase inhibitors, 5-FU = 5-fluorouracil Penetrating keratoplasty (PK) is a surgical intervention that despite the progress of surgical techniques and of postoperative treatment continues to have numerous complications. Many of them, such as graft rejection, significant astigmatism, cystoid macular edema, or cataract lead to important limitations of the visual function. Glaucoma is possibly the most dangerous complication following PK, leading to loss of the visual potential of the eye due to irreversible damage to the optic nerve, contrary to other complications, in which visual recovery can be expected.1].Glaucoma following PK has a relatively high frequency, it can appear early, as well as late in the evolution of the transplant, it is very hard to diagnose and also to follow-up and the medical or surgical treatment can interfere negatively with the evolution of the corneal graft [2]. Subsequently, different studies showed a variable incidence of glaucoma after PK, ranging from 9 to 31% early postoperatively and from 18 to 35% in the late postoperative period . One of the reasons for this great variation of incidence is the different manner in which glaucoma after PK is defined in various studies [5].In 1969, Irvine and Kaufman were the first to publish a study that emphasized the increased incidence of high intraocular pressure (IOP) after PK. The maximum mean IOP in the first postoperative week was 24 mmHg in phakic eyes, 40 mmHg in aphakic eyes and 50 mmHg in eyes that underwent combined surgery - cataract and transplant .Therefore, multiple studies define post-PK glaucoma as an elevation of IOP greater than 21 mmHg, independent of the optic nerve or visual field modifications. The definition obviously has scientific deficiencies, but has an important practical component .The most significant risk factors are preexisting glaucoma, lens status  and the disease for which PK is performed [3].In a study from 2014, Hemanth et al. compared the incidence of glaucoma after PK in phakic, pseudophakic, and aphakic eyes. The aphakic group had the highest risk, followed by the pseudophakic and phakic group; there was no statistically significant difference between the last two groups . In another study, Kirkness and Mashegov demonstrated an increased incidence of post-PK glaucoma after corneal perforations, especially those after bacterial ulcers, due to the formation of peripheral anterior synechiae (PAS). The longer the period between the perforation and the transplant, the higher the risk of glaucoma [10].Kirkness and Ficker published one of the greatest studies on the incidence and risk factors associated with post-PK glaucoma, that included 1122 PKs, performed at Moorfields Eye Hospital, London. The incidence of post-PK glaucoma was 14%. Corneal dystrophies and keratoconus had the lowest risk of glaucoma, contrary to bullous keratopathy, anterior segment trauma, iridocorneal endothelial syndrome and corneal perforations that had an increased risk .Other causes are not specific to post-PK glaucoma, also appearing after other types of surgical interventions; they should be promptly recognized and treated: pupillary blockage, lens induced glaucoma, hyphaema and viscoelastic retention [11].Zimmerman et al. demonstrated how the TM’s collapse, especially in aphakic eyes, is the main cause of glaucoma; they advocated that for an easy access through the anterior chamber angle to the trabecular meshwork, the trabeculum needs a posterior fixation, sustained by the ciliary body-lens complex and an anterior fixation at the level of Descemet membrane (DM). In aphakic and pseudophakic eyes the posterior support is relaxed due to lens removal. On the other side, the incision through DM in PK relaxes the anterior support, the DM being capable of displacing towards the angle [12].In 1975, using a mathematical model, Olson and Kaufman pointed out the factors that contribute to the distortion of the angle and so to the reduction of the outflow: tight sutures (widen the gap between the margins of the incision in the DM), lengthy sutures (compress even more the tissues), large grafts and thick peripheral corneas .In the immediate postoperative period, the diagnosis is based principally on measuring the IOP; later, to the extent possible (transparency of the cornea and ocular media), the classical evaluation is approached [1]. In cases of irregular surface, IOP can be measured with the Mackay-Marg electronic tonometer, the pneumotonometer [13] or the Tono-Pen [14]. Comparing the iCare tonometer with the GAT, Salvetat et al. demonstrated that the values are comparable in cases of anterior and posterior lamellar keratoplasty, but are different in cases of PK, the iCare tonometer underestimating pressure compared to the GAT [15]. Epithelial and stromal edema lead to the under evaluation of IOP and the measurement on a scarred tissue can give false raised values. Dynamic contour tonometer was imagined for measuring IOP independent of the mechanical properties of the cornea, which theoretically makes it very useful in eyes with keratoplasty, in which these properties are profusely modified. A digital piezoelectric pressure transducer is directly coupled to the ocular surface contour and directly measures the IOP transcorneally. More studies showed that this tonometer’s measurements are closer to the true manometric measurements than the other ones are [5]. Comparing the dynamic contour tonometer and the GAT in cases with keratoplasty, Ceruti et al. proved that the tonometer was not influenced by thickness, curvature, and corneal astigmatism [16].High astigmatism, graft edema, thick fluorescein meniscus and inappropriate mires  make Goldmann applanation tonometry (GAT) practically impossible [Prophylaxis5], because multiple studies revealed a higher incidence of graft failure if the intervention for glaucoma was performed after keratoplasty [17]. Other authors recommend trabeculectomy with mitomycin C (MMC) application or artificial drainage systems concomitantly with PK [17-19].Preexistent glaucoma should be well controlled prior to the surgical intervention. If the IOP is difficult to control with drugs or if the control imposes maximal therapy, the IOP can decompensate after keratoplasty. Therefore, it is recommended that in these cases, the glaucoma should be controlled surgically and afterwards the transplant should be performed . Deep sutures allow a better coalescence of the host and graft DM [11] and relatively short and equal sutures between graft and host compress the tissues to a lesser extent, both elements attenuating the TM’s tendency to collapse. In case of PAS, goniosynechialysis can be performed. Viscoelastic substances should be removed as completely as possible at the end of the intervention. In case of atrophic iris or floppy-iris syndrome, iridoplasty can be performed to tension the iris and to remove it from the angle [22]. Graft suture should be tight, avoiding iris incarceration at the graft-host junction, as well as the dehiscence of the plague postoperatively.In the case of PK, certain elements of the surgical technique can lower the risk of postoperative glaucoma. A graft 0.5 mm larger than the host opening is associated with a lower frequency of glaucoma after PK .Beta-blockers are effective in lowering IOP and the effect installs rapidly. This group of agents can be utilized for IOP spikes in the perioperative period, but also for long-term therapy. In prolonged use, the adverse effects are punctate epithelial keratopathy and corneal anesthesia that can affect the graft’s epithelium, compromising it .Topical CAI are well tolerated, do not have the systemic adverse reactions of the systemic administration and can be combined with other topical antiglaucomatous drugs. However, carbonic anhydrase has a role in the pump function of the corneal endothelium. Some studies showed endothelial decompensation with corneal edema in cases of borderline endothelial function. For this reason, it is recommended to stop therapy when edema of the corneal graft appears .Prostaglandin analogues efficacy is renowned, are administered once daily and have few systemic adverse effects. Because the effect installs relatively slow, these agents are suited for chronic forms of post-PK glaucoma. They should be avoided in PK for herpetic keratitis, because recurrence of herpetic keratitis has been reported and also the possibility of inducing cystoid macular edema should be taken into account . Considering that the effect of Argon laser trabeculoplasty is limited in time, that it can lower IOP with a maximum of 8-10 mmHg and that in the majority of cases, the angle of PK patients has PAS and a tendency for collapse of the TM, with difficult visibility, we consider that this option of therapy should be avoided in the treatment of glaucoma after PK.Argon or selective laser trabeculoplasty can be used in selected cases, with transparent graft, open angle, moderate pressure (25-30 mmHg) with medical treatment at a few months after keratoplasty, that allow the application of the lens. Van Meter et al. reported IOP control with Argon laser trabeculoplasty in 10 out of 14 cases for 2 years [Surgical treatmentTrabeculectomy27].Standard trabeculectomy has a low rate of success due to extensive subconjunctival fibrosis (after prior interventions) and the presence of PAS that numerous times are extended towards the graft-host junction and make the functioning of the fistula difficult. A study performed on 35 PK patients showed that 92% of them required medication after trabeculectomy and 53% necessitated further surgical interventions [28].5-fluorouracil (5-FU) can be administered for many days postoperatively via subconjunctival injections. It has a toxic effect on the corneal epithelium and can compromise the graft. The incidence of epithelial toxicity can be as much as 50% of the cases [7]. It is applied for 1 to 4 minutes intraoperatively and does not appear to have toxicity on the corneal epithelium. In a retrospective study on patients with glaucoma after PK, trabeculectomy with MMC had a higher success rate concerning IOP control (73%) in comparison to standard trabeculectomy (25%) for a follow-up period of 22 months [29]. Clarity of the graft was present in 69.2% of the cases from the lot with MMC and in 37.5% of the cases from the standard trabeculectomy lot. On the other side, the MMC group had a greater incidence of choroidal detachment, macular edema and fistula of the filtering bleb.Because of the corneal toxicity of 5-FU, most surgeons prefer MMC [30]. This loss of endothelial cells can compromise the graft. In order to assure a relatively deep postoperative chamber, an over-tight suturing of the scleral flap and subsequent laser lysis of these sutures can be considered.All measures for preventing anterior chamber collapse intra- and postoperatively should be taken. Endothelial cell loss after trabeculectomy is of 7-12% in case of iridocorneal contact and of 40-50% in case of corneolenticular contact .From a theoretical standpoint, inserting an artificial drainage device has some advantages compared to trabeculectomy. The filtering bleb is located posteriorly, possibly avoiding perilimbal fibrosis. Overfiltration with postoperative hypotony and collapse of the anterior chamber can be avoided either by using devices with valves (i.e. Ahmed implant) or by provisory suturing of the tube (i.e. Molteno implant). The success rate in reducing IOP after PK is 60 to 80% [31-33].Artificial drainage devices have their disadvantages. They are more expensive, require a higher surgical experience and the most important, have a relatively higher risk of graft failure than trabeculectomy [34]. The most important mechanism is the mechanic one, the tube being implanted in the anterior chamber and even though at the moment of implantation it is distant from the graft’s endothelium, it can displace afterwards.A mechanism of graft failure in eyes with artificial drainage devices could be immunological; the tube apparently allows the access of inflammatory cells from the subconjunctival space into the anterior chamber that could contribute to graft rejection [35].To avoid injuring the endothelium, the valve’s tube can be implanted at the level of the pars plana. The success rate in the control of IOP is similar, but there is a higher rate of retinal complications  .Cyclocryotherapy has been used from the 1950s in the treatment of refractory glaucoma. The success rate in the control of IOP is satisfying (60-90%), but is mainly replaced by cyclophotocoagulation, because of the great rate of serious complications . The success rate in IOP control varied from 69 to 77% with a follow-up period of 2 years. However, a high rate of graft failure (23-46%) appears and also, other severe complications such as: hypotony, phthisis bulbi .Nd:YAG laser cyclophotocoagulation is a more predictable method, less painful and with a lower rate of complications [40].Diode laser cyclophotocoagulation with a 810 nm wavelength has some advantages: the laser is portable, easier to manipulate and as effective as the Nd:YAG laser. Okacoglu et al. showed a rate of success of 92% in IOP control at 6 months and of 72% at 12 months in patients with post-PK glaucoma. 44% of the patients had to be retreated to obtain the control of the IOP, but no graft rejection was reported in the 32 patients of this study [It is difficult to assess which surgical treatment option - trabeculectomy with antimetabolites, implantation of an artificial drainage device or cyclophotocoagulation - is the most useful in the treatment of glaucoma after PK. As demonstrated, there are numerous studies on series of cases, generally retrospective, but there are no prospective, randomized studies that compare the treatment options.From our point of view, the future belongs to cyclophotocoagulation. Trabeculectomy with antimetabolites, as well as artificial drainage devices interfere with the anterior chamber and any intervention at this level increases the risk of graft failure. Probably a perfected variant of the existing cyclophotocoagulation lasers that would reduce the rate of complications related to hypotony, even if the intervention was periodically repeated, would theoretically have the highest chances of success.Glaucoma is a complication of PK very difficult to treat. Identifying the risk factors allows an attentive follow-up and rapid treatment of the postoperative IOP rises. Possibly, the most important fact is that preexisting glaucoma should be rightly diagnosed and controlled before PK, medically or, if necessary, surgically.Certain technical details can reduce the incidence of TM’s collapse and implicitly the appearance of glaucoma after PK.Once the glaucoma has installed, the medical treatment can control the IOP in certain cases and antiglaucomatous surgical interventions also contribute to the control of IOP.Graft failure can appear relatively frequently after surgical interventions, especially in those in which important inflammation at the level of the anterior chamber or mechanical injury of the corneal endothelium develop.DisclosuresNone of the authors has any financial or proprietary interests to disclose.


Zirconia implants in the mandible showed comparable %BIC to titanium implants  (p = 0.087). High failure rate of both Zr and Ti one-piece implants in the jaw could be attributed to the one-piece design and surface characteristics of the implant that could have influenced osseointegration. Further clinical trials are recommended to evaluate the performance of zirconia implants under loading conditions.Reports have documented titanium (Ti) hypersensitivity after dental implant treatment. Alternative materials have been suggested including zirconia (Zr) ceramics, which have shown predictable osseointegration in animal studies and appear free of immune responses. The aim of the research was to investigate the bone-to-implant contact (BIC) of one-piece Zr, compared with one-piece Ti implants, placed in the jaws and femurs of domestic sheep. Ten New Zealand mixed breed sheep were used. A One-piece prototype Ti (control) and one Zr (test) implant were placed in the mandible, and one of each implant (Ti and Zr) was placed into the femoral epicondyle of each animal. The femur implants were submerged and unloaded; the mandibular implants were placed using a one-stage transgingival protocol and were nonsubmerged. After a healing period of 12 weeks, %BIC was measured. The overall survival rate for mandibular and femur implants combined was 87.5%. %BIC was higher for Zr implants versus Ti implants in the femur  ( Implant dentistry using titanium dental implants has revolutionized the treatment of partially and fully edentulous patients . HoweverEven though titanium has been used as a biomaterial for more than 50 years, several reports have identified its potential toxicity . RecentlOne of the zirconia compounds is Yttria-stabilized tetragonal Zirconia-polycrystal (Y-TZP), which has been suggested as an alternative to titanium as it has similar biocompatibility and mechanical properties and has a more aesthetically acceptable colour than the metallic grey of titanium , 17. ZirThe use of animal models is an essential step in the testing of new biomaterials prior to use in humans. There are many animal models for dental implant research, each having differences in bone remodelling and bony architecture, with potential advantages and disadvantages . Sheep hThe majority of researchers have used rabbits and minipigs to evaluate zirconia implants , 22. Zir in vivo studies were strictly followed throughout the study. Each sheep received one Ti (control) and one Zr (test) implant in the mandible (right and left) and in the femoral epicondyle (right and left) . The implants were Ø3.8 mm in diameter and 10 mm in length for the mandible and Ø5 mm in diameter and 10 mm in length for the femur. Ball abutments were 3.1 mm in diameter for wider implants (5 mm) and 2.25 mm for the standard diameter implants (3.8 mm). Implants were placed in the mandibular premolar sites and in the femurs of each sheep.Ten adult New Zealand mixed breed female sheep aged 4-5 years and with average weight of 65 kg were used in this trial. The study was approved by the Animal Ethic Committee, University of Otago, Dunedin, New Zealand. The ARRIVE guidelines for preclinicalnd left) . One-piend left) . The impThe animal surgeries were carried out at the Department of Laboratory Animal Services at the University of Otago, New Zealand. The sheep were weighed before the commencement of the anaesthesia. Sheep were fasted prior to surgery and preoperative antibiotics were administered (penicillin/streptomycin 3 mL/kg IM). Anaesthesia was induced with thiopentone 20 mg/kg i.v., and an endotracheal tube was passed orally. General anaesthesia was maintained with halothane (1-2% to effect) and nitrous oxide/oxygen in a ratio of 2 : 1.An atraumatic approach for the extraction of the teeth was adopted. Under general and local anaesthesia, a mucoperiosteal flap was raised around the three mandibular premolars on each side of the lower jaw and the teeth were loosened with periotomes and elevators and then sectioned with a tungsten carbide tapered fissure bur and removed in pieces. The oral wounds were closed with resorbable Dexon™ 3/0 sutures  Figures . Dental After 12 weeks of healing following dental extractions, the sheep were returned to the Department of Laboratory Animal Services  and starved, anaesthetized and prepared as before.Jaw Surgery. A standard surgical procedure for implant placement was used under sterile conditions at all times. A flap was raised in the healed edentulous ridge from which the mandibular premolar teeth were removed, and one implant on each side of the jaw per sheep was placed accompanied by irrigation with copious chilled saline to prevent overheating . Mandibular and femoralμm was prepared. The slides were stained with a solution containing one part MacNeal's tetrachrome  and two parts toluidine blue. Sections were viewed using an Olympus Vanox-T microscope at 2x magnification  and digital images were captured using a Diagnostic Instruments SPOT RT Colour camera .All specimens were dehydrated and embedded in methyl-methacrylate at approximately 10°C. Specimens were then sectioned longitudinally using an R330 diamond wheel on a Struers Accutom-50® precision cut-off saw . Sections were then prepared to a final grit size of 4000 and final section thickness of 80–100 Histomorphometric analysis of bone-to-implant interface can be measured in various ways including thread volume fill (volume of bone found within an implant thread), % of bone-to- implant contact (% BIC) on the implant surface of the entire implant, or the % BIC of the “three consecutive best threads.” Histomorphometric analysis of the three best threads has been a well-documented method of measuring osseointegration . The stuThe data were analysed using GraphPad PRISM® software . A pair-wise comparison between zirconia (test group) and titanium (control group) was performed. Wilcoxon signed rank was used for nonparametric comparison of nominal, nonnormal paired data.The anaesthesia and the extraction of the mandibular premolars were uneventful, and all sheep recovered well. No postoperative complications were observed during the first week of healing and the animals were returned to the farm until the second stage of surgery (implant placement) and no significant changes in the weight were noted.Animals were weighed before anaesthesia to note any significant changes in the eating patterns after the removal of the mandibular premolars. No significant changes in the weight were observed. Four extraction sockets remained unhealed and/or infected (4/20), so implants were placed distal to these sites to prevent infection at the implant site.All animals survived jaw and femur (implant) surgery and were available for evaluation. Clinical evaluation of the mandibular implants revealed that three implants were lost, while two implants were loose . The oveThe histological images were classed into four categories: “integrated” (the first bone-implant contact was at the first thread and the implant was well integrated for the entire length), “failing” , “not integrated” (the implant is surrounded with fibrous connective tissue), and “lost” (the implant had been lost at postmortem).p = 0.18). Overall bone-implant integration was 11/20 = 55%.Gross histological evaluation of the Ti mandibular implants showed 7/10 implants were integrated, while the other three were failing. On the other hand, 3/10 Zr implants had failed and been lost, 2/10 were not integrated, one was failing, and only 4/10 could be considered successfully integrated. No statistical significant difference was found (p = 0.15).All implants appeared integrated in the femur. Condensation of bone was observed around the unloaded femoral implants, which has been described previously in trabecular bone  and whicp = 0.087). When the results from the two different surgical sites are considered, bone-implant contact for zirconia implants was 85.5% (SD 14.1) in the femur and 72.2% (SD 23.7) in the mandible. For titanium implants, % BIC was 60.3% (SD 22.4) for the mandible . Similarly in the jaw, zirconia implants also showed greater % BIC compared with titanium implants; however, the difference was not statistically significant, and there was a much higher incidence of negative outcomes, particularly for the one-piece zirconia implants.The present study showed successful osseointegration of zirconia and titanium implants in the experimental animals. Zirconia implants showed greater values for % BIC after 12 weeks of healing in the sheep mandible and femur. All submerged implants in the femur showed excellent osseointegration and zirconia implants showed evidence of an influence on the surrounding bone bed. A statistically significant difference was noted in the % BIC of zirconia implants when compared to titanium implants  with jaw implants (nonsubmerged). The literature has ascribed implant failure to a number of factors including initial stability, poor bone quality (types II and IV), implants placed in heavy smokers, nonsubmerged implants, immediately placed implants, small and/or short implants, inexperienced surgeon, and implants in fresh extraction sockets . StudiesThe outcomes of this research supported the results of other studies that have demonstrated higher failure rates of one-piece zirconia implants in clinical conditions , 49. OneOne-piece zirconia implants showed good osseointegration in the sheep femur. However, the high failure rate of both zirconia and titanium one-piece implants when placed into an intraoral site in the lower jaw reflects earlier studies showing poorer results with one-piece implant systems placed using a single-stage protocol. Further clinical trials are recommended to evaluate the performance of zirconia implants under loading conditions.


We investigated whether information in ClinicalTrials.gov would impact the conclusions of five ongoing systematic reviews.We considered five reviews that included 495 studies total. Each review team conducted a search of ClinicalTrials.gov up to the date of the review’s last literature search, screened the records using the review’s eligibility criteria, extracted information, and assessed risk of bias and applicability. Each team then evaluated the impact of the evidence found in ClinicalTrials.gov on the conclusions in the review.Across the five reviews, the number of studies that had both a registry record and a publication varied widely, from none in one review to 43% of all studies identified in another. Among the studies with both a record and publication, there was also wide variability in the match between published outcomes and those listed in ClinicalTrials.gov. Of the 173 total ClinicalTrials.gov records identified across the five projects, between 11 and 43% did not have an associated publication. In the 14% of records that contained results, the new data provided in the ClinicalTrials.gov records did not change the results or conclusions of the reviews. Finally, a large number of published studies were not registered in ClinicalTrials.gov, but many of these were published before ClinicalTrials.gov’s inception date of 2000.Improved prospective registration of trials and consistent reporting of results in ClinicalTrials.gov would help make ClinicalTrials.gov records more useful in finding unpublished information and identifying potential biases. In addition, consistent indexing in databases, such as MEDLINE, would allow for better matching of records and publications, leading to increased utility of these searches for systematic review projects.The online version of this article (10.1186/s13643-018-0726-5) contains supplementary material, which is available to authorized users. Information biases, including publication bias, time-lag bias, selective outcome reporting bias, and selective analysis bias, are major threats to the validity and usability of systematic reviews. Systematic reviewers have pursued two method approaches for dealing with information bias. One is to detect (and possibly correct results for) information bias based only on the identified studies , are a good source of this information. Regulations established in 1997 and expanded under the Food and Drug Administration Amendments Act of 2007 , NationaEmpirical analyses of prospective registration of studies  can inform on the time between study completion and publication, the number of unpublished studies, the fidelity of studies to registered protocols, and the congruence of study results between registry records and publications –18. The The objective of this project was to assess whether information from ClinicalTrials.gov would affect the conclusions of five ongoing systematic reviews.To assess the impact of information derived from ClincialTrials.gov on systematic reviews, five ongoing systematic reviews were selected. Our goal was to measure prospectively the resource use and payoff of ClinicalTrials.gov searches in real-time across a variety of topics. The full method sections for each project are reproduced in Additional file The Agency for Healthcare Research and Quality sent a request for proposals to members of their network of evidence-based practice centers for analysis of the evaluation of ClinicalTrials.gov data in ongoing reports. From the submitted proposals, they chose to fund five projects that were based in different clinical areas and populations and spanned different types of interventions, in order to evaluate the impact across as broad a range as possible. The selected reviews include as follows: Prevention and treatment of diabetic peripheral neuropathy , Evaluatstudy is the actual research conducted, a record is the ClinicalTrials.gov report of the study, and a publication is a journal article report of the study. Each of the five case studies is referred to as a project. The original systematic review on which each project is based is the report.For the purposes of this project, a These five projects were conducted by four separate EPCs to ensure consistency in searching and screening between the systematic reviews and the report –29. DetaStudies were matched to publications using the citations listed in the “More Information” section of the Study Details tab of the ClinicalTrials.gov record or the National Clinical Trial (NCT) number given in the MEDLINE® record. Where no match could be identified using the NCT identifier, the teams manually searched MEDLINE using terms for the interventions and principal investigator as search criteria.https://effectivehealthcare.ahrq.gov/topics/transparency-reporting/overview/).Each team abstracted selected variables from the ClincalTrials.gov records to determine whether key study design variables and reported outcomes matched information in the published manuscript. Variables abstracted matched those extracted from reports for the systematic reviews and included date of completion, number of study arms and N of the study, intervention description, study design, outcomes measures, analysis approach and subgroup analyses, numerical results, and risk of bias. Each team then evaluated the impact of the evidence found in the registries on the conclusions and strength of evidence in the report in different ways. The project protocols were prospectively published on the AHRQ Web site  International Clinical Trials Registry Platform (ICTRP) , 26. ThiIn assessing the impact on the systematic review of the records found, the teams looked at three categories of studies. The first category included studies that had both a ClinicalTrials.gov record and a publication. For these studies, each team compared the record to the publication, in terms of design details, population description, sample size, details about the interventions, outcomes, and results if they were given. If results were identified in the record that were not found in the publication, these were incorporated into the review as applicable. The second category included studies that had a record in ClinicalTrials.gov but no publication. For these studies, the team documented the study status  and relevant dates. If the record reported results, these were extracted using the forms used for the original review and incorporated into the systematic review if they were applicable and usable. The final category included studies with a publication but no record. These studies were evaluated for potential reasons why they were not included in the registry.As Table We found relatively good agreement between the registration records and publications, where we found both, especially when it came to the design elements and intervention descriptions, as well as in specific results where they were included in the record. We did find some discrepancies in lists of outcomes between how the outcomes were pre-specified in the record and reported in the publication . For example, in the tympanostomy tubes project, of the 28 total relevant records, only 15 were prospectively registered, and none of the six records with matching publications was prospectively registered .Between 11 and 30% of all studies had a record but no associated publication  were completed more than 3 years earlier , enough time that the results should be published. Seven of these 13 studies reported results in ClinicalTrials.gov . In the project on treatment for infertility, the team devoted an estimated 74.5 total hours to the ClinicalTrials.gov searches, screening, and analyzing new evidence . Better The primary limitation of this project is that it was performed by four separate teams, using different protocols for different topic areas. While the protocols were similar in concept, they differed in some specifics. For example, one project did not look at adverse event data .A second limitation is that two of the projects were relatively small, including few studies , 28, andA third limitation is that most projects limited their registry searches to ClinicalTrials.gov and may have missed studies registered in other trials. However, the two projects that also searched the WHO ICTRP’s registry found very few new studies, none of which had results , 26.Finally, it is important to note that this article is summarized from a case series of five systematic reviews, albeit on a range of topics, and thus the results should be interpreted with caution and may not be generalizable.Searches of ClinicalTrials.gov records did not influence the conclusions of five systematic review projects, and we were unable to draw conclusions about reporting bias due to lack of information in the records. Improved prospective registration of trials and consistent reporting of results in ClinicalTrials.gov would go a long way to make ClinicalTrials.gov records more useful in finding unpublished information and identifying potential biases. In addition, more consistent indexing in databases, such as MEDLINE, and in ClinicalTrials.gov would allow for better cross-matching of records and publications, leading to increased utility of these searches for systematic review projects.Additional file 1:Methods from Each Project. (DOCX 46 kb)


Most research on the political consequences of international migration conceptualizes financial remittances as being a substitute for state-provided assistance. This paper tests the actual validity of this assumption. Using data from the 2012–2016 Americas Barometer, the analysis confirms previous findings on the negative impact of financial remittances on electoral turnout intentions. However it reveals that this effect does not vary according to an individual’s beneficiary status of Conditional Cash Transfer (CCT) assistance. This finding is corroborated using data aggregated at the municipal level within Mexico. Accordingly, voter turnout rates in a given municipality for the 2012 presidential election are negatively associated with the percentage of households receiving remittances in that municipality. However, this association does not vary with the spending on CCT assistance within a given municipality. The evidence thus suggests that financial remittances undermine electoral participation through mechanisms other than the substitution of state-sponsored assistance, and as such further research is needed for us to discover what is really going on here. Cash transfers can be delivered in the form of social assistance (by the state) or as remittances (by migrants). Existing studies demonstrate that both public and private transfers of money improve receivers’ well-being – by reducing poverty, vulnerability and other risks associated to financial shocks or unexpected expenses  have expanded significantly over the years , the largest anti-poverty CCT program in Mexico. This finding is corroborated using data aggregated at the municipal level. According to statistical models, turnout rates for the 2012 presidential election in a given municipality are negatively associated with the percentage of households receiving remittances in it. However, this association does not vary with the spending on this CCT program in a given municipality. These findings hold after controlling for a series of factors affecting electoral turnout at the individual and aggregate levels. The evidence thus suggests that financial remittances undermine electoral participation through mechanisms other than the substitution of state-provided assistance.The paper is organized as follows. First, it provides background on international remittances and CCT assistance in Mexico. Second, it reviews the existing literature on the electoral consequences of international remittances and CCT assistance in the country. Based on this, it advances a series of hypotheses about the interactive effects of financial remittances and CCT assistance on voter turnout in Mexico. Third, it describes the quantitative data and methods that are used for testing these claims. Fourth, it presents and analyses the results obtained through a series of statistical models. Fifth, it discusses these findings and concludes by suggesting new avenues of research on how financial remittances shape electoral participation, not only in Mexico.Mexico is the world’s fourth-largest recipient of remittances , and the largest in Latin America , 49% of remittance receiving households in the country benefit from various forms of state-sponsored assistance, including: Oportunidades (Prospera), Procampo, Apoyo Alimenticio, Empleo Temporal, and other such social programs. By contrast, only 30% of the households that do not receive remittances from abroad benefit from state assistance— in the form of the Oportunidades or other such social programs. Approximately 31% of remittance-recipient households in Mexico are located in the first two income deciles. Within the first income decile, 58% of remittance-recipient households benefit from state-sponsored assistance; within the second income decile, 62% do so  the incumbent party through electoral means. In sum, although international remittances increase the disposable income of recipients, which, according to resource models of political participation, should increase the likelihood of voting  substitutes, we should expect that the effects of international remittances on voter turnout vary with the receipt of CCT assistance. In other words, receipt of remittances decreases the likelihood of a person voting—but this effect changes by the receipt of CCT assistance from the government. The following hypotheses can therefore be advanced:To test the above claims, I use two approaches. The first one uses individual data, and tests whether receiving CCT assistance influences the intentions of remittance recipients to participate in presidential elections. The second approach uses data aggregated at the municipal level and tests whether spending as part of the Oportunidades program affects the impact of international remittances on turnout rates for the 2012 presidential election across different municipalities of the country.Individual-level data is drawn from the 2012–2016 waves of the Americas Barometer, carried out by the Latin American Public Opinion Project (LAPOP) at Vanderbilt University. I utilize this particular survey because it allows us to distinguish individuals’ electoral participation patterns and statuses as remittance recipients and CCT beneficiaries. Of all the Americas Barometer waves available since 2008, I only use those for 2012–2016. In previous waves of this survey, Mexican participants had only been asked whether themselves or their family members had received any monthly assistance from the state in the form of money or goods. From this question alone, it is difficult to identify what type of social assistance was received (whether it was in cash or kind), whether it was delivered with conditions or without conditions, to whom (who the beneficiaries are), and from what government level . Since 2012, however, Mexican respondents have been explicitly asked whether they are beneficiaries of the Oportunidades (Prospera) program or not.The main dependent variable is electoral turnout intentions. It is a binary variable, coded 1 if respondents said they would vote, if the next presidential election was being held this week, and 0 otherwise.The main independent variables are: individuals’ status as remittance receiver and as CCT assistance beneficiaries. Remittance-recipient status is registered as 1 if respondents answered affirmatively to the question “Do you, or someone in your household, receive money from abroad?” and 0 otherwise. Meanwhile, the status of being a beneficiary of CCT is coded as 1 if respondents answered affirmatively to the question “Do you, or someone in your household, receive monthly assistance as part of the Oportunidades (Prospera) program?” and 0 otherwise.The statistical models account for other factors that, according to previous research, affect the likelihood of an individual showing up at the polls. These include: previous voter turnout, partisanship, support for democracy, trust in elections, political interest, social membership, and crime victimization.The estimation strategy consists of a series of linear probability models. One concern, however, is that individuals who receive remittances are not randomly selected. In correcting for this, I employ a matching procedure, which consists of pairing individuals with similar characteristics into two groups—with one group receiving the treatment, and the other not. In this study, the treatment group is the one that receives remittances. Pretreatment variables are respondents’ work situation, income earned through labor (or pensions), size of place of residence, and household size. This is because remittance recipients are more likely to: be unemployed or lack a stable labor income, be low-income earners themselves, reside in rural areas of the country, and live in households with various dependents. By adjusting for the distribution of covariates between remittance recipients and nonrecipients, matching can allow us to separate the effect of remittances from other factors shaping individuals’ electoral turnout intentions—and thus to create more valid comparisons. Individuals who receive CCTs are also likely to be non-randomly selected. However the pretreatment variables used for matching can allow us to correct for the non-random selection of CCT recipients as well, since they also tend to lack a stable income, be low-income earners, reside in rural areas, or live with other dependent relatives.To match respondents, I use the exact matching procedure, which matches observations together if they are identical on a set of covariates. Those observations that are not matched are discarded.As a robustness check, I re-run the analysis using aggregate data at the municipal level. Aggregate data was compiled for all of the Mexican municipalities that participated in the 2012 presidential election. However complete data was available for 2443 such municipalities. In 2012 Mexico had 2456 municipalities—in other words, 13 are unaccounted for. The aggregate data used in the analysis comes from a variety of sources. Information on electoral participation rates was collected from the National Electoral Institute of Mexico (INE). Data on international remittances comes from the Mexican National Population Council (CONAPO), and is based on the 2010 Mexican census conducted by the Mexican National Institute of Statistics and Geography (INEGI). Information on CCT assistance and the socioeconomic and demographic characteristics of municipalities was collected from INEGI and the National Council for the Evaluation of Social Development Policy CONEVAL, .The dependent variable is turnout in the 2012 presidential election, whereas the main dependent variables are the proportion of households receiving remittances and the spending in Oportunidades per 1000 habitants in a given municipality.The analysis based on aggregate data is limited to the cross-sectional level. This is because the relevant municipal-level data on international migration indicators as well as socioeconomic ones is only gathered every 10 years. Also, since the proportion of households receiving remittances in a given municipality and the CCT spending allocated to a particular municipality are not randomly assigned, there is a risk that model estimates could be biased. To address this, instrumental variables are used to enable the prediction of the random assignment of these two variables. These are: the proportion of households that received remittances in a given municipality in 2000, and the number of people aged under 15 per 1000 habitants in a given municipality.All estimations were conducted using R. To correct for further heterocedasticity, robust standard errors are used in all of the models.Table Table Table To reiterate, the aim of this paper is to examine whether the relationship between international remittances and voter turnout changes with the delivery of CCT assistance. Model 2 includes an interaction term, which estimates the additional effects of CCT assistance on electoral turnout intentions among individuals receiving international remittances. As seen in Model 2 in Table , the intAdditionally, Models 1 and 2 in Table  tell us To further investigate the interactive effects of CCT assistance and international remittances on voter turnout, I specify a series of models using data aggregated at the municipal level. Table To examine whether the relationship between remittances and voter turnout varies in the context of the delivery of the Oportunidades program, Model 6 in Table  includesIt should be noted that, in the specifications based on data aggregated at the municipal level, the instrumental variables used pass the “weak instruments” and “Wu-Hausman” tests. These assess the strength of the instruments, and the consistency of the 2SLS estimation as compared to OLS respectively.14Overall, the statistical analysis confirms that international remittances do indeed undermine voter turnout in Mexico. Analogous results were obtained by Goodman and Hiskey  for the Hence the evidence suggests that international remittances have a negative effect on voter turnout in Mexico, irrespective of whether the recipients also benefit from cash transfers from the government. The findings thus suggest that the mechanisms through which international remittances influence voter turnout are other than by the substitution of state-provided assistance for remittances. This is an important contribution to the literature on the political consequences of international migration in sending countries, which has commonly attributed the negative effects of international remittances on voter turnout to the substitution of international remittances for state-sponsored assistance. In light of these new insights, the question that researchers on the political economy of remittances should now look at is: Why are international remittance recipients still less likely to vote even when benefiting from cash assistance from the state?One possible explanation for these as yet unexplained discrepancies is that the amount of money that CCT beneficiaries receive is not in itself sufficient to satisfy a household’s needs—and therefore its electoral impact is ultimately negligible. In effect, even though CCT assistance has succeeded in reducing the number of people living in extreme poverty in Mexico it has simultaneously been ineffective in reducing the overall number of people living below the national poverty line  benefits cannot be rescinded due to recipients’ political orientation or activities. Also, the program itself is safeguarded against political manipulation by a ruling that prevents its coverage being extended during a federal election year. However, in the Mexican context it is likely that remittance recipients might consequently see the delivery of CCT  as vote buying—and thus they prefer not to participate in elections shape the attitudes and behavior of recipients toward politics—and indeed the state in general (Pérez-Armendáriz & Crow, Clearly this study has its limitations. Scholars should corroborate the findings presented herein using different estimation strategies and alternative data that allows for distinguishing the remittance behavior of emigrants, the spending patterns of receivers, the extent to which remittances and cash assistance are fungible, and the electoral participation patterns of receivers. In-depth qualitative evidence and ethnographic accounts could shed further light on the joint electoral effects of remittances and CCT assistance. This study also focuses on only one social intervention, the Oportunidades program, and therefore only on the population segment benefiting from this type of CCT assistance—that is, the poor with young children. Further studies should examine whether these findings hold true when considering other sections of the population, and other types of state assistance, such as noncontributory pensions, health insurance schemes and unemployment benefits. In this regard, an interesting line of research would be to examine the interactive effects of subsidies to consumption and international remittances on electoral participation.Another limitation of this study is that it considers only one type of political participation: voting. Further research should explore the ways in which international remittances interact with CCT programs, or other forms of state-sponsored assistance, and affect other types of political participation—such as protests, lobbying, or town hall meetings Burgess, . Althoug


Neurochemical Research dedicated to Professor Jan Albrecht, a truly enthusiastic biochemist forever bursting with ideas, always giving the impression that he is permanently dealing with a plethora of different topics and pursuing countless amounts of activities simultaneously. At seventy-two, he simply continues to be the person he has been all through his life: an outspoken and often uncompromising researcher with an incredibly sharp analytical skill, an internationally acknowledged expert in many different fields of neurochemistry.It is a privilege to write this preface in the special issue of Professor Albrecht was born in 1944 in Warsaw and it was there he received his education. He is a graduate of biochemistry from the Department of Biology, University of Warsaw, and after being a voluntary assistant at the State University of Leiden (The Netherlands), he obtained his PhD in biochemistry there at the Department of Chemistry. Back in Poland, he joined the Department of Neuropathology in the Mossakowski Medical Research Centre (MMRC), Polish Academy of Sciences in Warsaw. In 1980 he obtained “doctor habilitatus” (second doctorate) in molecular biology . In 1996, he became the head of the Department of Neurotoxicology in the Mossakowski Medical Research Centre, PAS, serving there since 2014 as Professor Emeritus.In the early 1980s, Professor Albrecht was one of the first to recognize the role of astrocytic dysfunction in the pathogenesis of hyperammonemia and hepatic encephalopathy. Before that, in the Leiden period, Professor Albrecht characterized in detail the ribosomal initiation factor causing dissociation of bacterial ribosomes to the 30 S and 50 S subunit , 3 and oNeurochemical Research, Journal of Neuroscience Research, Neurochemistry International, Frontiers in Bioenergetics, Metabolic Brain Disease, Molecular and Chemical Neuropathology and Journal of Neurochemistry. He is a member of learned societies and committees such as the Polish Academy of Sciences and Art, the Polish Academy of Sciences, the American Society for Neurochemistry, the European Society for Neurochemistry, the International Society for Developmental Neurosciences, the Polish Neuroscience Society, the Committee of Neurobiology PAS, the Committee of Physiological Sciences PAS. Since 2013, Professor Albrecht is a member of Academia Europaea. He also serves as a member on many research councils, which is highly esteemed by the scientific community. Among the prizes that he has received are the Award of the Prime Minister of Poland for outstanding achievements in science and the Award of the Foundation for Polish Science (Master Programme).The scientific work of Professor Albrecht has led to more than 220 publications and chapters, which have been cited more than 3500 times (current H-index 30). His research has brought him international recognition. Professor Albrecht is an outstanding lecturer, who has delivered dozens of lectures around the world at prestigious meetings, including the very last Hans Prydz Lecture in University of Oslo in the year 2012. Professor Albrecht served and continues to serve as the valued member of editorial boards in many top-ranking journals, including Wide scientific international contacts allowed Professor Albrecht to co-organize and co-chair “Wierzba Conferences”, a cyclic triennial event gathering top European and overseas experts in the field of glutamate metabolism and function in healthy and diseased brain . One looks forward with great anticipation to the next scientific contributions that Professor Albrecht will make in the coming years.creation of this issue published in his honor.To honor Professor Albrecht, this Special Issue comprises contributors that reflect on the broad range of his interests in neurochemical research. He will be particularly thrilled to note that so many of the researchers in the field who are his long-term friends and collaborators participated in the Magdalena Zielińska & Michael AschnerGuest Editors


The proportion of granule types in wheat starch is an important characteristic that can affect its functionality. It is widely accepted that granule types are either large, disc-shaped A-type granules or small, spherical B-type granules. Additionally, there are some reports of the tiny C-type granules. The differences between these granule types are due to its carbohydrate composition and crystallinity which is highly, but not perfectly, correlated with the granule size. A majority of the studies that have considered granule types analyse them based on a size threshold rather than chemical composition. This is understandable due to the expense of separating starch into different types. While the use of a size threshold to classify granule type is a low-cost measure, this results in misclassification. We present an alternative, statistical method to quantify the proportion of granule types by a fit of the mixture distribution, along with an R package, a web based app and a video tutorial for how to use the web app to enable its straightforward application.Our results show that the reliability of the genotypic effects increase approximately 60% using the proportions of the A-type and B-type granule estimated by the mixture distribution over the standard size-threshold measure. Although there was a marginal drop in reliability for C-type granules. The latter is likely due to the low observed genetic variance for C-type granules.The determination of the proportion of granule types from size-distribution is better achieved by using the mixing probabilities from the fit of the mixture distribution rather than using a size-threshold.The online version of this article (10.1186/s13007-017-0259-2) contains supplementary material, which is available to authorized users. Starch derived from the endosperm of cereal grains is the major source of carbohydrate in the human diet and has many functional uses in food and non-food industries. Starch is made up of two distinct components, amylopectin (70–80% dry biomass) and amylose, which are organised into water-insoluble granules during synthesis (for a review see ). DistriArabidopsis thaliana starch synthase III and IV have been implicated in the initiation of transitory starch granules [In starch storage organs, as well as photosynthetic tissue, many enzymes involved in transitory starch biosynthesis have been shown to influence the size of starch granules. These include ADP-glucose pyrophosphorylase , starch granules , 21, howPerhaps more immediately, an ability to produce cereal starch with optimised starch granule type and size would be of great use in industrial applications of starch. An increased proportion of A-type granules is preferable in many industrial settings, since smaller B-type granules are easily lost during starch isolation. A-type and B-type granules have different chemical and structural properties, notably, A-type and B-type granule have a disc and spherical shapes respectively  with difTo study the proportion of granule types in a starch sample, it is therefore necessary to be able to discriminate between granule types. A true quantification of granule types would be based on separation of granules based on composition or origin ; howeverGranule size distributions of wheat starch show clear multi-modality, either bimodal , 5 or trStarch granule types are highly correlated with their size, as such almost all studies use a size-threshold for classification: large, small and tiny granule sizes correspond to A-type, B-type and C-type granules respectively. The threshold used to classify the granule types differs from study to study, however, most use the diameter size of 9.9–10 μm as a cutoff between A-type and B-type granules , 6, 7, 9We present an alternative method to accurately quantify the proportions of each granule type in a starch suspension by use of a mixture distribution. We show this ‘mixture measure’ provides a significant difference to the ‘size-threshold measure’, and represents an important step forward in accurately estimating granule populations in cereal starch.A field trial of a diverse wheat population was grown in Yanco, NSW, Australia in 2009 as part of the GRDC CSP112 project. Grain from 155 genotypes was milled, and 5 g of flour was weighed into 50 ml screw capped tubes. The flour was treated with 50 ml of 1% (w/v) sodium metabisulphite in 0.05M NaCl for 30 min rotating on an ELMI RM-2L Intelli-mixer  at 40 rpm. The resulting batter was ultra-sonicated in a Soniclean160T  water bath for 1 minute and passed through 200 μm nylon mesh. The filtrate was sonicated a further 1 min. The sonicated filtrate was then centrifuged at 5100 rpm in a Sigma 4K15 bench top centrifuge and swing out head Nr. 11150. The pellet was resuspended in 20 ml of 90% Percoll (Life Technologies) and centrifuged at 1500 rpm. The upper phases were poured off the primary starch pellet which was washed three times with Milli-Q water. The isolated starch was resuspended in 5 ml of Milli-Q water, frozen and freeze dried for particle size analysis.p-rep designs [Field, milling, extraction and measurement phases of the experiment were conducted according to  designs , which w designs . BrieflyThe freeze dried starch was suspended in Milli-Q water, briefly vortexed and starch granule size distributions were determined using a Mastersizer 2000 particle size analyser , which measures the percentage of the total starch volume for a given diameter size interval.We compared two approaches to produce summary statistics for the different granule types. The first (size-threshold measure) was the typical method that previous studies have used, and the second (mixture-measure) involved extracting information from fitted mixture distributions. To the best of our knowledge, the statistics from the latter method have not been used previously to characterise starch granule types.To determine suitable thresholds by which to classify the granule types, we fitted a mixture of three Gaussian distribution to the log of the particle size diameter averaged over all samples Fig. . For theBecause it is the structural and the chemical composition, as well as spatio-temporal origins, that separates the granules into different types rather than size alone, we implemented an alternative method to draw descriptive statistics for the granule types. The plot of the particle diameter size for most genotypes shows a clear trimodal distribution. This distribution appears to be a mixture of three log-normal distributions and thus a mixture of three Gaussian distribution was fitted to the log of particle diameter size for each sample. We interpreted the mixing weights of the three individual component distributions as the proportions of each granule type for the corresponding sample.There are several statistical packages available for fitting Gaussian mixture distributions. We chose to use mixdist  for the All the fits were checked by visual inspection to assure all the fitted distributions matched the data. Of the 864 particle size measurements, 30 appeared to have a quad-modal distribution and two extraction had a better fit with a mixture of five Gaussian distributions , define peaks interactively and download tabular and graphical output.t test for the mean difference of the percentages show that there is a significant difference between the two methods  particle size that was well fitted by a mixture of three Gaussian distribution. The mixing weights associated with the fit of this distribution serves as a better estimation of the proportion of granule types. This was reflected in the observation of a significantly higher reliability for A-type and B-type granules for the mixture measure than the conventional size-threshold measure, although we note this was not the case for C-type granule. The reason for the latter may be due to factors such as the lower machine precision for distribution of smaller particle sizes or the size-threshold measure incorrectly classifying the smaller B-type granules as C-type granules when the B-type granule may be a more highly heritable trait. The latter is indeed supported by the small genetic variance associated for C-type granule as seen in Additional file One huge disadvantage of the size-threshold measure is that a threshold must be specified for the classification of the granule types. There is no consensus for this threshold across the literature and rather our data suggest variability for an appropriate threshold of each sample, probably owing to different genotype-environment interaction. On the contrary, the mixture-measure does not require specification of a threshold for the classification of the granule types and additionally provides standard errors associated with the estimate of the proportions.The mixture-measure may be sensitive to the initial values of the parameters and the users should be wary to visually check the fit of the distribution.We advocate the use of the mixture-measure over the size-threshold measure as a more accurate estimate of the A-type and B-type granule population in starch samples. Our experimental data shows a significant difference between the two measures and it is clear the size-threshold measure would likely over-estimate or under-estimate the population size of the granule-types with such a rigid classification of the granule-types.


Our usual virtual June meeting has arrived. This year we can see a number of positive trends: more and higher quality submissions, an explosion in the downloaded paper numbers, hyperactive social media, and finally a slight but significant increase in the Impact Factor.Since 2008 the Impact Factor has doubled, and is now the highest it has been since the journal launched: 3.580. We are now in the first quartile of Clinical Neurology journals. The journal also demonstrated solid scientific relationships with other journals in the field, with citations both to and from a broad spectrum of journals.We are still confident in the foundation of the journal: a historic act, driven by a desire to serve, rather than hubris. This can still be seen in the daily interaction between SpringerNature Editorial Office, and the affiliated scientific societies; favoring the speediness of interactions among authors and reviewers, and awarding ideas and quality.The journal has never aimed to be an archetype, only a megaphone for every scientist involved in headache research. Our growth has surely benefited from a European history made by giants, but in time we have stepped down their shoulders with courage, despite some trepidation. Needless to say, being a whisker from the top is a pleasure mitigated only by the awareness that such positions, once reached, must be maintained or increased.The Journal of Headache and Pain.Our success doesn’t depend on single very highly-cited articles, and we don’t want it to . We can


Superabsorbent hydrogels show a large potential in a wide array of applications due to their unique properties. Carboxymethylcellulose (CMC) is a commercially available water-soluble cellulose derivative of major interest in the hydrogel synthesis. High-energy irradiation allows the chemical crosslinking without the use of crosslinking agents, while the introduction of other natural or synthetic polymers offers a convenient way to modify the gels. In this study we examined the effect of the addition of starch, a low-cost renewable polysaccharide, on the properties of carboxymethylcellulose-based hydrogels.water/ggel was achieved with ~55% gel fraction synthesized from 15 w/w% solutions at 20 kGy. Heterogeneous gel structure was observed: the starch granules and fragments were dispersed in the CMC matrix. The swelling of CMC/starch gels showed a high sensitivity to the ionic strength in water due to the CMC component. However, the mixed gels are less sensitive to the ionic strength than pure CMC gels.Superabsorbent gels were prepared by gamma irradiation from aqueous mixtures of carboxymethylcellulose and starch. The partial replacement of CMC with starch improved the gel fraction, while a slight increase in the water uptake was also observed. However, very high starch content had a negative impact on the gelation, resulting in a decrease in gel fraction. Moreover, higher solute concentrations were preferred for the gelation of CMC/starch than for pure CMC. Hydrogels containing 30% starch showed the best properties: a water uptake of ~350 gThe introduction of starch to carboxymethylcellulose systems led to improved properties. Such gels showed higher water uptake, especially in an environment with high electrolyte concentration. CMC/starch hydrogels may offer a cheaper, superior alternative compared to pure cellulose derivative-based gels depending on the application. Superabsorbent hydrogels are special materials capable of absorbing huge amount of water, usually more than 100 or even 1000 times of their dry weight, reaching much higher water content than conventional hydrogels , soil coA wide array of polymers is used for superabsorbent production. Most commercial products are based on polyacrylates, but other synthetic polymers are also used, usually as copolymers with acrylates. However, there is a significant and ever growing interest in the use of natural materials for superabsorbent preparation. The focus of these studies is mainly on the most common and cheapest renewable resources, such as the cellulose , chitosaCellulose is the most abundant renewable material in the world. However, due to its insolubility in water , for hydN,N′-methylene-bisacrylamide (MBA) [3+ as well [Carboxymethylcellulose-based hydrogels are prepared from aqueous solutions with several crosslinking methods. Crosslinking agents like polycarboxylic acids , epichlode (MBA)  are comm as well . For the as well . A great as well . The gel as well  and atmo as well . Radiati as well . However as well . The swe as well , 23.Starch is also a very cheap renewable resource, which is mostly used as a copolymer in synthetic polymer-based gels. Starch solutions are usually pregelatinized by heat treatment before the copolymerization to achieve a more homogeneous structure. Its free-radical crosslinking can be initiated either by initiator system , 25 or bStarch-based hydrogels combined with other renewable materials were not studied in-depth; while there is some literature available for starch/chitosan hydrogels , such geThe goal of this work was to prepare cheaper CMC/starch hydrogels with improved superabsorbent properties as compared to pure CMC based gels. The gelation was achieved by gamma irradiation, without the use of crosslinking agents or other additives. The effect of the starch content on the gel properties at various synthesis conditions was examined. Moreover, the changes in various swelling properties such as the salt sensitivity with the blend ratio of the two components were also in-depth studied.w = 700,000 g mol−1, Ds = 0.9, analytical grade), potato starch and NaCl  were purchased from Sigma-Aldrich and were used without purification.Carboxymethylcellulose Na-salt  and after (w1) the washing was used to determine the gel fraction:Samples were immersed in deionized water to remove the sol fraction. A liquid:gel ratio of 1000:1 was used and the water was periodically changed. After 48 h the gel was removed by a metal sieve and dried to constant weight at 60 °C. The weight of the dry sample before (ws) and the dry (wd) gel was used for the calculation of the degree of swelling:After the removal of the sol fraction the samples were dried and then immersed in deionized water at a liquid ratio of 1000:1. After 24 h the swollen gels were weighed and dried to constant weight at 60 °C . The weight of the swollen  was used to record the IR spectra of freeze-dried gel samples. The spectra were recorded at a resolution of 8 cmJSM 5600 V scanning electron microscope was used to study the morphology of the gels. Freeze-dried gels were used for sample preparation: they were cut and the cross-section was coated with gold. SEM images were recorded with 25 kV accelerating voltage at 35× to 1000× magnification.The effect of three important synthesis parameters was studied in-depth: carboxymethylcellulose:starch ratio, solute concentration and absorbed dose.The effect of starch content on the gel properties was studied at 10, 20 and 40 kGy absorbed dose. Pure CMC systems showed low gelation at 10 kGy, only a gel fraction of 7% was observed. At higher doses the gelation improved significantly and 35–40% gel fraction was reached. The replacement of 5–10% CMC with starch significantly increased the gel fraction at all doses  the crosslinking is the main process [In aqueous solutions the radical processes are initiated mainly by the reactive intermediates  formed in the radiolysis of water. Below a certain solute concentration radiation induced direct chain scission is negligible. In the presence of dissolved oxygen the reactions of hydroxyl radicals should only be considered as the other two intermediates reacting with oxygen transform to the less reactive Ogh yield , 40. The process , 39. In The starch granules also participate in the crosslinking process, leading to improved gelation: the CMC chains react with the granule surface through the recombination of the radicals formed on both polymers. The radical formation in the starch is similar to the reaction observed for the CMC due to the similar chemical structure. In this case the reaction is not hindered by electrostatic repulsion like during the crosslink formation between two CMC chains. The irradiation also affects the properties of the starch: the degradation processes lead to a decrease in the degree of polymerization, lower swelling and a more amorphous structure , 42. Thiwater/ggel due to the poor gelation. Higher doses led to a major decrease in the swelling , resulted by the higher crosslink density. Interestingly, similarly to the gel fraction, the water uptake also showed a small increase in the presence of starch  was observed at high starch content using lower doses. The slight increase may be explained by the lower CMC content. Substituting CMC with starch has a similar effect as lowering the solute concentration, because the CMC concentration in the matrix is lower. At lower CMC concentration the water uptake increases due to the lower crosslink density in the CMC phase, which allows a larger expansion of the polymer network.The swelling of pure CMC gels differed significantly depending on the adsorbed dose. At 10 kGy they exhibited a water uptake of ~300 gThe morphology of gels with different starch content was studied by SEM Fig. . CMC/sta−1 wavenumber range. In case of CMC gels several characteristic peaks were observed [−1 range is attributed to the ether bonds in the cellulose backbone. The ionized carboxyl groups (COO−) show two absorption peaks at 1580 and 1410 cm−1 due to the symmetric and asymmetric stretching. Smaller peaks at 1321 and 1268 cm−1 can be assigned to the stretching vibrations at C=O and OH groups. In comparison, pure starch powder has a significantly different IR spectrum. Between 1150 and 1000 cm−1, similarly to the carboxymethylcellulose, peaks related to the COC stretching are observed [−1 instead of the dual peak observed with 1017 and 1052 cm−1 for CMC. Low intensity bands at 1700–1600 cm−1 also appear, probably due to the water present in the amorphous phase.The gel composition of various CMC/starch gels was determined using FTIR-ATR Fig. . The IR observed . An absoobserved . However−1, the intensity of this band did not decrease. However, the peak at 1017 cm−1 became less sharp due to the absorption of starch at 995 cm−1. The change of the IR spectra shows the presence of both polymers in the gel, thus both components participate in the formation of the gel fraction.In the IR spectra of CMC/starch gels, all the absorption peaks observed at pure CMC gels were also present. However, the intensities of the carboxyl absorption peaks became lower with increasing starch content, as starch does not contain carboxyl groups. As both polymers show a high absorption at 1150–1000 cmwater/ggel. No significant change in gel content was observed up to 50 kGy while the swelling decreased constantly reaching 200 gwater/ggel for both gels at 40 kGy. For gels of 50% starch content no change in the swelling was observed, while for gels of 30% starch content the swelling ability slowly decreased, reaching 150 gwater/ggel at 100 kGy.Based on previous results we concluded that the effect of absorbed dose on the gel properties should be investigated in more detail. It was studied at three different carboxymethylcellulose:starch ratios. For pure carboxymethylcellulose solutions, at doses lower than 8 kGy the formation of very loosely crosslinked systems with relatively low water uptake was observed Fig. . The sepThe effect of solute concentration was determined with samples irradiated with 10 and 20 kGy absorbed doses Fig. . Very loThe water uptake monotonously decreased with the solute concentration Fig. b. This iLowering the dose to 10 kGy resulted in lower gel fraction but higher water uptake. Moreover, the critical solute concentration required for gelation and the maximum of the gel fraction shifted towards higher concentrations. CMC solutions at 10 kGy showed low gelation, the gel fraction being under 15% in the whole solute concentration range. While the gel fraction of CMC/starch gels also decreased due to the lower absorbed dose, over 20 w/w% it was still higher than for CMC gels synthesized at 20 kGy. At 20 w/w%, the gel fractions of CMC (20 kGy) and CMC/starch (10 kGy) gels were similar, but the latter had significantly higher water uptake. CMC solutions crosslinked at 10 kGy showed even higher swelling at higher solute concentrations due to the very weak network formation, but this also led to a very low gel fraction.water/ggel water uptake and relatively high (~55%) gel fraction, significantly higher than observed for pure CMC hydrogels. Moreover, the swelling properties of these gels were higher than those of the carboxymethylcellulose-based superabsorbents with the same gel fraction prepared with crosslinking agent [Based on the results, hydrogels containing 30% starch showed the best properties, as large improvement in the gelation was achieved with good swelling properties as compared to pure CMC based gels. Lowering the solute concentration proved to be more effective  in the improvement of the water uptake than changing the dose, the optimal properties requiring 15 w/w% solute concentration and 20 kGy dose. Such systems exhibited ~350 gng agent  or introng agent . On the −3 concentration NaCl solutions  and gel fraction (~55%), significantly higher than observed for pure CMC gels (200 gwater/ggel and 35%). Moreover, the presence of the starch also led to a lower sensitivity to the solvent properties such as the electrolyte content. While responsive behavior is crucial for several applications, in certain fields such as the agriculture only the very high water absorption capacity is utilized. In such conditions the application of carboxymethylcellulose/starch systems, which exhibit good swelling properties but lower sensitivity to the presence of salts or the pH of the soil, may be favored to pure polyelectrolyte-based superabsorbents.Hydrogels with superabsorbent properties were successfully prepared from carboxymethylcellulose/starch solutions. The addition of starch resulted in an increase both in the gel fraction and in the water uptake at relatively low doses. While starch alone is a radiation degradable polymer, in the presence of CMC the radicals formed on the starch chain will react with radicals on the CMC chain, leading to crosslinking instead of degradation. The partial replacement of the carboxymethylcellulose with starch up to a certain ratio offers an alternative to pure CMC gels with increased swelling in water. The optimal synthesis parameters proved to be 30% starch content, 15 w/w% solute concentration and 20 kGy absorbed dose. Such superabsorbent showed both high water uptake (~350 g


Our purpose was to analyze possible associations between histogram analysis parameters of dynamic contrast-enhanced magnetic resonance imaging DCE MRI and histopathological findings like proliferation index, cell count and nucleic areas in head and neck squamous cell carcinoma (HNSCC).trans, Ve, and Kep were estimated using a mathlab based software. Tumor proliferation index, cell count, and nucleic areas were estimated on Ki 67 antigen stained specimens. Spearman's non-parametric rank sum correlation coefficients were calculated between DCE and different histopathological parameters.30 patients (mean age 57.0 years) with primary HNSCC were included in the study. In every case, histogram analysis parameters of Ktrans min  and s Ktrans skewness , Ve min , Ve entropy , and Kep entropy . Cell count correlated with Ktrans kurtosis , Ve entropy . Total nucleic area correlated with Ve max  and Ve entropy .KI 67 correlated with Ktrans entropy correlated well with total  and average nucleic areas . In G3 tumors, KI 67 correlated with Ve min  and Ve entropy . Ve max correlated with total nucleic area . Kep max correlated with total area , and Kep entropy with KI 67 .In G1/2 tumors, only Ktrans, Ve, and Kep can be used as markers for proliferation activity, cellularity and nucleic content in HNSCC. Tumor grading influences significantly associations between perfusion and histopathological parameters.We concluded that histogram-based parameters skewness, kurtosis and entropy of K Accort cancer . Addition glioma . In HNSCn glioma .et al. showed that ADC histogram parameters can well differentiate T and N stages in gastic cancer [et al., histogram parameters of MR perfusion can distinguish between oligodendroglioma and astrocytic tumors [Currently, a new approach of imaging analysis, namely histogram analysis of different radiological parameters is in trend. So some reports indicated that histogram analysis parameters of apparent diffusion coefficient (ADC) can better reflect several morphological features in different malignancies in comparison to established ADC parameters –12. For c cancer . Also hic tumors . Furtherc tumors .Presumably, histogram based DCE MRI parameters are more sensitive to reflect histopathololgical features than mean values used in clinical practice.The purpose of this study was to analyze possible associations between histogram analysis parameters of DCE MRI and histopathological findings like proliferation index, cell count and nucleic areas in HNSCC.trans min  and Ktrans skewness  . Ve min correlated with KI 67  and Ve max with total nucleic area . Ve entropy showed significant correlations with KI 67 , cell count , and total nucleic area . Finally, Kep entropy correlated with KI 67 .Correlation analysis identified several statistically significant correlations and correlation trends between the investigated parameters. KI 67 correlated with K5) Table . Furthertrans entropy correlated well with total  and average nucleic areas   and Ve entropy  . In addition, Kep max correlated with total area , and Kep entropy with KI 67 .In G3 tumors, KI 67 correlated with VThe present study identified associations between different DCE MRI parameters derived from histogram analysis and histopathological findings in HNSCC.e is one of the independent prognostic factors for neck control in HNSCC treated with chemoradiation [et al. investigated lymph node metastases in HNSCC and found that low pretreatment Ktrans was associated with a poor response to concurrent chemoradiation therapy [et al. showed that lower pretreatment Ktrans correlated with shorter disease-free survival [As mentioned above, previously, numerous studies analyzed DCE MRI findings in HNSCC –21. It hadiation . Further therapy . Finallysurvival .et al. identified statistically significant correlations between KI 67 and Ktrans, Ve, as well between Kep and vascular endothelial growth factor (VEGF) in neck nodal metastases of HNSCC [The reported results suggested that DCE MRI parameters should be associated with relevant histopathological features in HNSCC. Previously, only two studies analyzed possible relationships between DCE MRI and histopathology in patients HNSCC , 22. So of HNSCC . Presumaof HNSCC  mean valof HNSCC . This fae and Kep should be associated with cellularity. This suggestion seems to be logical. In fact, Ve represents volume of the extravascular extracellular space [e and cellularity should be inversely, namely more cells-less extracellular space and vice versa. In fact, in an experimental study with glioma model, a strong inverse correlation (r = −0.75) between Ve and cellularity could be identified [We hypothesize that DCE MRI should have more significant correlations with histopathology than reported previously. Especially Var space , 24 and,entified .ep reflects diffusion of contrast medium from the extravascular extracellular space back to the plasma [trans and microvessel density in several malignancies [trans correlated with proliferation activity (KI 67 expression) in hepatocellular carcinoma [trans reflects diffusion of contrast medium from the plasma through the vessel wall into the interstitial space [Similarly, Ke plasma , 24, andgnancies , 9. Alsoarcinoma . Howeverarcinoma , 9. On tal space , 24, andtrans and Ve and tended to correlate with several percentiles of both parameters. Furthermore, stronger correlations were observed between histogram-based parameters skewness, kurtosis and entropy and different histopathological findings. So kurtosis of Ktrans correlated statistically significant with cell count and tended to correlate with KI 67, and skewness of Ktrans correlated with KI 67. Entropy of Ve correlated with KI 67 expression, cell count, and total nucleic area. Finally, entropy of Kep correlated with KI 67. In contrast to the previous reports, neither standard deviation nor mean values of the investigated perfusion parameters showed significant correlations with histopathological findings. These findings indicated the following: firstly, routinely used perfusion parameters  are non sensitive to reflect relationships with cellularity and proliferation activity in HNSCC. Secondly, histogram-based parameters are better associated with proliferation activity, cellularity and nucleic areas in HNSCC. This finding is very important for clinical practice and implicates use of histogram-based DCE MRI parameters to predict histopathological features in HNSCC.The present study confirmed these assumptions. Here, interestingly phenomena were identified. Proliferation activity slightly correlated with the minimum of KFurthermore, our study identified also another phenomenon, namely associations between perfusion parameters and histopathology is different in different tumor grades. Significantly more correlations and trends are seen in G3 tumors than in low grade lesions. The exact cause of this finding is unclear. Presumably, high grade carcinomas have other architecture, including relationships between tumor cells, especially cell size or volume and extracellular space, as well nucleic-cytoplasmic ratio. Also other features like stroma and microvessel density etc. may also play a role. These factors results in different associations between histopathology and perfusion parameters derived from DCE MRI. Clearly, further works with more cases are needed to confirm this hypothesis. Also search for relevant associations between histogram analysis DCE MRI parameters and other histopathological features like invasiveness should be performed in HNSCC.trans, Ve, and Kep can be used as surrogate markers for proliferation activity, cellularity and nucleic content in HNSCC. Tumor grading influences significantly associations between perfusion parameters and histopathologic findings.In conclusion, histogram analysis DCE MRI parameters are sensitiver than mean DCE MRI values to reflect associations with histopathology in HNSCC. Especially, histogram-based parameters skewness, kurtosis and entropy of KThis study was IRB-approved and all patients gave their written informed consent.Overall, 30 patients  with histological proven primary HNSCC were included in the study. The diagnosed tumors were localized in the oropharynx 46.7%), tongue (23.3%), hypopharynx (10%), larynx (16.7%), and nasopharynx (3.3%). Most frequently, the identified lesions were staged as T3 (33.3%) or T4 tumors (40%) with additional nodal (90%) metastases  in a dose of 0.1 mmol per kg of body weight was started after the fifth scan at a rate of 3 ml per second and flushing with 10 ml of normal saline using a power injector . Thereafter, all acquired images were transferred to a software module for tissue perfusion estimation  as described previously [In all patients dynamic contrast-enhanced (DCE) imaging of the neck was performed. In every case, dynamic T1w DCE sequences  included 40 subsequent scans à 6 seconds were applicated. Intravenous administration of contrast medium ;Vep or parameter for diffusion of contrast medium from the EES back to the plasma.Ktrans, Ve, and Kep), mean, maximal, minimal, and median values, as well percentiles 10th, 25th, 75th, and 90th were estimated . Thereafter, polygonal ROIs were automatically drawn on all of the transferred maps along the contours of the primary tumor on each slice (whole lesion measure) according to the previous description . For eveIn every case, sections from formalin-fixed and paraffin-embedded tissue were cut at 5 μm and stained with Ki 67 antigen . Thereafter, the histopathological images were digitalized by using the Pannoramic microscope scanner  with Carl Zeiss objectives. In every case, the whole sample was acquired at high resolution. Via the integrated Pannoramic Viewer 1.15.4  the acquired slides were evaluated and three captures with a magnification of ×200 were extracted and saved as uncompressed Tagged Image File Format (TIFF). Furthermore, the digitalized images were analyzed by using ImageJ software 1.48v  with a Windows operating system –30. For Tumor proliferation index as relation of KI 67 stained nuclei divided by all nuclei , 26. ThoCell count as a number of all nuclei;2) as area of all nuclei;Total nucleic area (μm2) as a total nucleic area divided by number of nuclei.Average nucleic area . Values are presented as mean ± standard deviation (SD). The distribution of the acquired data was tested by Shapiro-Wilk test. Mean value comparison was carried out using the Mann-Whitney-