Dynamics and drivers of mycorrhizal fungi after glacier retreat.

The development of terrestrial ecosystems depends greatly on plant mutualists such as mycorrhizal fungi. The global retreat of glaciers exposes nutrient-poor substrates in extreme environments and provides a unique opportunity to study early successions of mycorrhizal fungi by assessing their dynamics and drivers. We combined environmental DNA metabarcoding and measurements of local conditions to assess the succession of mycorrhizal communities during soil development in 46 glacier forelands around the globe, testing whether dynamics and drivers differ between mycorrhizal types. Mycorrhizal fungi colonized deglaciated areas very quickly (< 10 yr), with arbuscular mycorrhizal fungi tending to become more diverse through time compared to ectomycorrhizal fungi. Both alpha- and beta-diversity of arbuscular mycorrhizal fungi were significantly related to time since glacier retreat and plant communities, while microclimate and primary productivity were more important for ectomycorrhizal fungi. The richness and composition of mycorrhizal communities were also significantly explained by soil chemistry, highlighting the importance of microhabitat for community dynamics. The acceleration of ice melt and the modifications of microclimate forecasted by climate change scenarios are expected to impact the diversity of mycorrhizal partners. These changes could alter the interactions underlying biotic colonization and belowground-aboveground linkages, with multifaceted impacts on soil development and associated ecological processes.

The importance of species addition 'versus' replacement varies over succession in plant communities after glacier retreat.

The mechanisms underlying plant succession remain highly debated. Due to the local scope of most studies, we lack a global quantification of the relative importance of species addition 'versus' replacement. We assessed the role of these processes in the variation (ß-diversity) of plant communities colonizing the forelands of 46 retreating glaciers worldwide, using both environmental DNA and traditional surveys. Our findings indicate that addition and replacement concur in determining community changes in deglaciated sites, but their relative importance varied over time. Taxa addition dominated immediately after glacier retreat, as expected in harsh environments, while replacement became more important for late-successional communities. These changes were aligned with total ß-diversity changes, which were more pronounced between early-successional communities than between late-successional communities (>50 yr since glacier retreat). Despite the complexity of community assembly during plant succession, the observed global pattern suggests a generalized shift from the dominance of facilitation and/or stochastic processes in early-successional communities to a predominance of competition later on.

Local climate modulates the development of soil nematode communities after glacier retreat.

The worldwide retreat of glaciers is causing a faster than ever increase in ice-free areas that are leading to the emergence of new ecosystems. Understanding the dynamics of these environments is critical to predicting the consequences of climate change on mountains and at high latitudes. Climatic differences between regions of the world could modulate the emergence of biodiversity and functionality after glacier retreat, yet global tests of this hypothesis are lacking. Nematodes are the most abundant soil animals, with keystone roles in ecosystem functioning, but the lack of global-scale studies limits our understanding of how the taxonomic and functional diversity of nematodes changes during the colonization of proglacial landscapes. We used environmental DNA metabarcoding to characterize nematode communities of 48 glacier forelands from five continents. We assessed how different facets of biodiversity change with the age of deglaciated terrains and tested the hypothesis that colonization patterns are different across forelands with different climatic conditions. Nematodes colonized ice-free areas almost immediately. Both taxonomic and functional richness quickly increased over time, but the increase in nematode diversity was modulated by climate, so that colonization started earlier in forelands with mild summer temperatures. Colder forelands initially hosted poor communities, but the colonization rate then accelerated, eventually leveling biodiversity differences between climatic regimes in the long term. Immediately after glacier retreat, communities were dominated by colonizer taxa with short generation time and r-ecological strategy but community composition shifted through time, with increased frequency of more persister taxa with K-ecological strategy. These changes mostly occurred through the addition of new traits instead of their replacement during succession. The effects of local climate on nematode colonization led to heterogeneous but predictable patterns around the world that likely affect soil communities and overall ecosystem development.

T-cell receptor sequencing reveals selected donor-reactive CD8+ T cell clones resist antithymocyte globulin depletion after kidney transplantation.

High frequencies of donor-reactive memory T cells in the periphery of transplant candidates prior to transplantation are linked to the development of posttransplant acute rejection episodes and reduced allograft function. Rabbit antithymocyte globulin (rATG) effectively depletes naïve CD4+ and CD8+ T cells for >6 months posttransplant, but rATG's effects on human donor-reactive T cells have not been carefully determined. To address this, we performed T cell receptor ß-chain sequencing on peripheral blood mononuclear cells aliquots collected pretransplant and serially posttransplant in 7 kidney transplant recipients who received rATG as induction therapy. We tracked the evolution of the donor-reactive CD4+ and CD8+ T cell repertoires and identified stimulated pretransplant, CTV-(surface dye)-labeled, peripheral blood mononuclear cells from each patient with donor cells or third-party cells. Our analyses showed that while rATG depleted CD4+ T cells in all tested subjects, a subset of donor-reactive CD8+ T cells that were present at high frequencies pretransplant, consistent with expanded memory cells, resisted rATG depletion, underwent posttransplant expansion and were functional. Together, our data support the conclusion that a subset of human memory CD8+ T cells specifically reactive to donor antigens expand in vivo despite induction therapy with rATG and thus have the potential to mediate allograft damage.

Case Report: Human Tracheal Transplantation Undergoes Progressive Reepithelialization Over Time.

OBJECTIVES: Tracheal transplantation is an ideal option for the reconstruction of long-segment circumferential tracheal defects. Our group performed the first successful vascularized single-staged tracheal transplantation in January 2021. Although a rigid biocompatible structure is necessary for a functioning tracheal replacement, the importance of ciliated epithelium, which allows for critical mucociliary clearance, is now being appreciated. Here, we examined the histological changes of the first single-staged human tracheal transplant from serial endoscopic biopsies. METHODS: Biopsies of the tracheal mucosa were serially obtained since the time of the tracheal transplantation. Samples were examined via hematoxylin and eosin, electron microscopy, and immunohistochemistry. RESULTS: One week after transplantation, there is loss of ciliated epithelium and seromucinous cells, with only a basal layer of epithelium remaining. By 2 weeks, however, the epithelium begins to recover, albeit differently depending on the location of the biopsy. Near the site of tracheal anastomosis, there is epithelial proliferation, with the appearance of early ciliated cells. However, in the midgraft, there appears to be evidence of squamous metaplasia. Over time, however, normal ciliated epithelium and mucous cells appear without signs of chronic inflammation. CONCLUSIONS: Critically, the tracheal allograft regained normal appearing respiratory epithelium after initial ischemic injury. The histologic differences at the midgraft versus anastomosis may suggest unique mechanisms of reepithelialization. At the recipient-donor interface, there may be a faster direct migration of recipient-derived epithelial cells, in line with preclinical studies. The midgraft, in contrast, responds with epithelial proliferation from the donor basal cells or dedifferentiated mucous cells. LEVEL OF EVIDENCE: N/A Laryngoscope, 2023.

Llamas (Llama glama) enhance proglacial ecosystem development in Cordillera Blanca, Peru.

Worldwide, mountain glaciers are shrinking rapidly. Consequently, large areas are becoming available for the development of novel alpine ecosystems. These harsh environments, however, delay primary succession. In this study with a local community, we conducted an inclusion experiment to investigate whether Llama glama influences soils and vegetation primary succession following glacial retreat. At the foot of the Uruashraju glacier in the Cordillera Blanca, Peru (~ 4680 m.a.s.l.), we established four llama inclusion plots and four control plots that we studied from 2019 to 2022, 24-40 years after deglacierization. After three years, the llama plots had significantly increased soil organic carbon and soil nitrogen. In the llama plots, we found a large, significant increase in vascular plant cover (+ 57%) between the second and third years of experimentation, and we identified four new species that were not present in 2019. Our results suggest that Llama glama, through their latrine behavior and role as a seed disperser, enhances the primary succession and novel ecosystem formation in recently deglacierized landscapes. Our study provides scientific support that rewilding of native Andean camelids may favor adaptation to glacier retreat and inform conservation and management strategies in proglacial landscapes.

A multi-stakeholder multicriteria decision analysis for the reimbursement of orphan drugs (FinMHU-MCDA study).

BACKGROUND: Patient access to orphan medicinal products (OMPs) is limited and varies between countries, reimbursement decisions on OMPs are complex, and there is a need for more transparent processes to know which criteria should be considered to inform these decisions. This study aimed to determine the most relevant criteria for the reimbursement of OMPs in Spain, from a multi-stakeholder perspective, and using multicriteria decision analysis (MCDA). METHODS: An MCDA was developed in 3 phases and included 28 stakeholders closely related to the field of rare diseases (6 physicians, 5 hospital pharmacists, 7 health economists, 4 patient representatives and 6 members from national and regional health authorities). Initially [phase A], a bibliographic review was conducted to identify the potential reimbursement criteria. Then, a reduced advisory board (8 members) proposed, selected, and defined the final list of criteria that could be relevant for reimbursement. A discrete choice experiment (DCE) [phase B] was developed to determine the relevance and relative importance weight of such criteria according to the stakeholders' preferences by choosing between pairs of hypothetical financing scenarios. A multinomial logit model was fitted to analyze the DCE responses. Finally [phase C], the advisory board review the results using a deliberative process. RESULTS: Thirteen criteria were selected, related to 4 dimensions: patient population, disease, treatment, and economic evaluation. Nine criteria were deemed relevant for decision-making and associated with a higher relative importance: Health-related quality of life (HRQL) (23.53%), treatment efficacy (14.64%), availability of treatment alternatives (13.51%), disease severity (12.62%), avoided costs (11.21%), age of target population (7.75%), safety (seriousness of adverse events) (4.72%), quality of evidence (3.82%) and size of target population (3.12%). The remaining criteria had a < 3% relative importance: economic burden of disease (2.50%), cost of treatment (1.73%), cost-effectiveness (0.83%) and safety (frequency of adverse events) (0.03%). CONCLUSION: The reimbursement of OMPs in Spain should be determined by its effect on patient's HRQL, the extent of its therapeutic benefit from efficacy and the availability of other therapeutic options. Furthermore, the severity of the rare disease should also influence the decision along with the potential of the treatment to avoid associated costs.

Planning Abilities in Patients with Anorexia Nervosa Compared with Healthy Controls.

OBJECTIVE: Altered cognitive functioning could have an important role in the development and maintenance of Anorexia Nervosa (AN). The majority of previous research has focused on flexibility and global-detail processing. The aim of this study was to explore planning abilities in women with AN. METHOD: Women with AN (n = 32) were compared to healthy controls (n = 42) using two different types of neuropsychological tasks for the assessment of planning abilities: Tower of London (ToL), a classic measure of planning abilities, and Zoo Map test, a more ecologically valid planning measure. Measures of AN psychopathology, anxiety, depression, and obsessive compulsivity were also collected. RESULTS: The AN group did not differ from controls in the ToL (all p-values p > .05), although they performed significantly worse than controls in the main score of the Zoo Map (p = .02). A worse performance in the Zoo Map test More was associated with more eating disorders (rho = -.44, p = .018) and depressive (rho = -.42, p = .026) symptoms in the AN group. CONCLUSIONS: Our study suggests the presence of subtle planning difficulties in women with AN which might be better detected using tasks with increased ecological validity.

Bone mineral density aspects in the femoral neck of hip fracture patients.

Elderly people, due to neurological conditions and muscular atrophy, present a greater propensity to falls and thus are very susceptible to hip fractures. Other variables, such as osteoporosis, may also be related to the etiopathogenesis of hip fractures, although osteoporosis is in fact a concurrent disease, and merely a coadjutant cause. Nonetheless, osteoporosis can make fracture patterns more severe and interfere with osteosynthesis. Osteoporosis is the radiological image of osteopenia, a pathological concept meaning a smaller quantity of bone per unit of volume. The radiological expression of osteopenia is therefore that of bone tissue with a lower radiological density than normal. In the context of hip fractures, bone mineral density and bone architecture of the femoral neck together with protein expression profiles and cross-links of this anatomical area are of special interest which is reviewed in the current paper. Spatial variations in bone mineral density in the femoral neck were found in the literature with increased porosity from the periosteal to the endosteal region and also from the distal to the proximal part of the femoral neck. Furthermore, increased crystal size, increased cortical porosity, reduced osteocyte lacunar density and an increased Ca/P ratio associated with higher concentrations of Ca and P were described in hip fracture patients compared to control patients. Osteocalcin/collagen type 1 expression ratio and enzymatic cross-link content in high-density bone was found to be significantly lower in hip fractures compared to controls. In conclusion, further research in bone mineral density and associated parameters are of interest to deepen the understanding of osteoporotic hip fractures.

Resuscitation of Polytrauma Patients: The Management of Massive Skeletal Bleeding.

The term 'severely injured patient' is often synonymous of polytrauma patient, multiply-injured patient or, in some settings, polyfractured patient. Together with brain trauma, copious bleeding is the most severe complication of polytrauma. Consequently hypotension develop. Then, the perfusion of organs may be compromised, with the risk of organ failure. Treatment of chest bleeding after trauma is essential and is mainly addressed via surgical manoeuvres. As in the case of lesions to the pelvis, abdomen or extremities, this approach demonstrates the application of damage control (DC). The introduction of sonography has dramatically changed the diagnosis and prognosis of abdominal bleeding. In stable patients, a contrast CT-scan should be performed before any x-ray projection, because, in an emergency situation, spinal or pelvic fractures be missed by conventional radiological studies. Fractures or dislocation of the pelvis causing enlargement of the pelvic cavity, provoked by an anteroposterior trauma, and in particular cases presenting vertical instability, are the most severe types and require fast stabilisation by closing the pelvic ring diameter to normal dimensions and by stabilising the vertical shear. Controversy still exists about whether angiography or packing should be used as the first choice to address active bleeding after pelvic ring closure. Pelvic angiography plays a significant complementary role to pelvic packing for final haemorrhage control. Apart from pelvic trauma, fracture of the femur is the only fracture provoking acute life-threatening bleeding. If possible, femur fractures should be immobilised immediately, either by external fixation or by a sheet wrap around both extremities.

Factores asociados a injuria renal aguda en pacientes incidentes de un hospital general de Lima- Perú / Factors associated to acute renal injury in incident patients in a general hospital in Lima, Peru

Objetivos: Identificar factores asociados a la injuria renal aguda (IRA) en pacientes que acudieron a emergencia de un hospital general. Material y métodos: Estudio caso-control, se incluyeron 50 casos y 100 controles de pacientes incidentes a emergencia de un hospital III-B de Lima. Se analizó los datos mediante OR. Resultados: Los factores de riesgo encontrados fueron la condición de gravedad del paciente (OR=6,14), la presencia de un cuadro infeccioso como diagnóstico al ingreso, la existencia de sepsis y el estar en shock séptico (OR=2,85; 3,78 y 6,77 respectivamente). Las comorbilidades asociadas a la incidencia de IRA de la comunidad fueron: enfermedad respiratoria, alcohol y tabaco, neoplasia maligna y enfermedad neuropsiquiátrica (p=0,001). La edad, sexo y otras variables de filiación y situación socioeconómica no estuvieron relacionados. Conclusiones: Los factores asociados a IRA fueron la presencia de un cuadro infeccioso, su gravedad y la presencia de comorbilidades preexistentes. (AU)

Objectives: To identify factors associated to acute renal injury (ARF) in patients attending the emergency room of a general hospital. Methods: Case-control, study that included 50 cases and 100 controls. Association we determined by calculating odds ratios. Results: Factors identified were severity of illness (OR=6,14); an infectious process at admission (OR=2.85); sepsis (OR=3.78) and septic shock (OR=6.77). Comorbidities associated to ARF were alcohol and tobacco consumption, cancer and neuropsychiatric illness (p=0.001). Age, gender and other variables were not associated. Conclusions: Severity of illness and presence of an infectious disease on admission correlated with ARF. (AU)

Should hip fractures be operated upon only by specialist hip unit surgeons in order to lower rates of surgical site infection?

PURPOSE: The purpose of this study was to compare outcomes of hip fractures treated by orthopaedic surgeons, performed by specialist vs. non-specialist surgeons. The rate of surgical site infection (SSI) obtained is taken as the main variable. METHODS: This was a prospective controlled cohort study of 814 patients presenting with hip fractures, operated on by a group of orthopaedic surgeons within the same hospital department. Patients were classified according to whether the surgeons belonged to a specialist hip unit (group A = 212 cases) or not (group B = 602 cases). RESULTS: Multivariate logistic regression showed that there was no relation between gender, SSI, Charlson's index, preoperative period, surgical technique or study groups (A or B). Only age was a determinant factor (rank-sum test p = 0.03; OR 95% CI = 1.07, p = 0.005). CONCLUSIONS: Since there were no differences in the SSI outcome between surgeons working in a specialist hip unit and the general orthopaedic surgeons, delaying operative treatment for hip fractures to enable treatment in such a unit or creating a new unit of this type is not necessary. In this respect, the only significant variable is the patient's age.

Stability over time in the preferences of older persons for life-sustaining treatment.

OBJECTIVE: To measure the stability of life-sustaining treatment preferences amongst older people and analyse the factors that influence stability. DESIGN: Longitudinal cohort study. SETTING: Primary care centres, Granada (Spain). Eighty-five persons age 65 years or older. Participants filled out a questionnaire with six contexts of illness (LSPQ-e). They had to decide whether or not to receive treatment. Participants completed the questionnaire at baseline and 18 months later. RESULTS: 86 percent of the patients did not change preferences. Sex, age, marital status, hospitalisation, and self-perception of health and pain did not affect preferences. Morbidity and the death of a relative did. CONCLUSION: Stability of preferences of older persons in relation to end-of-life decisions seems to be more probable than instability. Some factors, such as the death of a relative or the increase in morbidity, can change preferences. These findings have implications for advance directives (ADs) and advance care planning.

Characterization of adult stem/progenitor cell populations from bone marrow in a three-dimensional collagen gel culture system.

Stem cell transplantation therapy using mesenchymal stem cells (MSCs) is considered a useful strategy. Although MSCs are commonly isolated by exploiting their plastic adherence, several studies have suggested that there are other populations of stem and/or osteoprogenitor cells that are removed from primary culture during media replacement. Therefore, we developed a three-dimensional (3D) culture system in which adherent and nonadherent stem cells are selected and expanded. Here, we described the characterization of 3D culture-derived cell populations in vitro and the capacity of these cells to differentiate into bone and/or cartilage tissue when placed inside of demineralized bone matrix (DBM) cylinders, implanted subcutaneously into the backs of rat for 2, 4, and 8 weeks. Our results demonstrates that 3D culture cells were a heterogeneous population of uncommitted cells that express pluripotent-, hematopoietic-, mesenchymal-, and endothelial-specific markers in vitro and can undergo osteogenic differentiation in vivo.

Occult acetabular fracture in elderly patients.

Acetabular fractures in the elderly are increasingly common; however, an antecedent of trauma may not be known, and the diagnosis easily missed. Early identification and prompt management are needed in order to minimise morbidity rates, but little has been published on occult acetabular fracture.In this paper we present three cases of occult acetabular fracture in patients older than 75 years. All three are females and had previously been operated on the ipsilateral hip with an implant (two proximal femur fractures treated with a proximal intramedullary femoral nail, and one case of total joint replacement); these acetabular fractures could be related to the existence of a stress shielding mechanism.We believe that whenever an elderly patient feels groin pain, and anteroposterior pelvis X-rays are normal, oblique Judet projections (obturator and iliac) should be obtained. In any case, displacement will make any fracture evident within a few weeks.

Role of mental disorders in nosocomial infections after hip fracture treatment.

The association between mental disorders (MDs) and iatrogenic complications after hip fracture surgery has been poorly studied. Among iatrogenic complications, nosocomial infections (NIs) are a major factor in hip fracture surgery. The aim of this paper was to determine whether patients with a MD and a hip fracture develop more NIs after hip surgery than patients with no MD. We studied 912 patients who underwent surgery for a hip fracture (223 patients with a MD who underwent surgery for a hip fracture and 689 control patients without a MD who also underwent surgery for a hip fracture) and followed them after surgery. Univariable and multivariable analyses were performed using simple and multiple logistic regression analysis (confidence interval, crude and adjusted odds ratios, and P value). We found that MDs, gender, and comorbidities were not associated with a higher risk of developing a NI after surgery for a hip fracture. Only age increases the risk of a NI.

Characteristics and publication patterns of theses from a Peruvian medical school.

BACKGROUND: Many medical schools require a student thesis before graduation. Publishing results in a peer-reviewed journal could be an indicator of scientific value and acceptability by the scientific community. The publication pattern of theses published by medical students in Peru is unknown. The aim of this study was to assess the characteristics and publication pattern of theses in biomedical-indexed journals conducted by medical students in a university with the highest research output in Peru. METHODS: Data from registered theses between 2000 and 2003 were obtained from the university library. Publication of theses in biomedical journals was assessed in 2008 by a search strategy using PubMed, Google Scholar, LILACS, LIPECS and SciELO. RESULTS: Four hundred and eighty-two medical theses were registered between 2000 and 2003; 85 (17.6%) were published in biomedical-indexed journals. Of the published theses, 28 (5.8%) were published in MEDLINE-indexed journals, 55 (11.4%) in SciELO-indexed journals, 61 (12.6%) in LILACS-indexed journals and 68 (14.1%) in LIPECS-indexed journals. Most of the published theses (80%) were in Spanish and published in Peruvian journals; and 17 theses (20%) were published in foreign journals (all of them indexed in MEDLINE). In addition, 37 (43.5%) belong primarily to internal medicine, and 24 (28.2%) belong primarily to infectious diseases. Medical students were first authors in 71 (83.5%) of the articles. CONCLUSION: In this study, most of the published theses were in Spanish, published in local journals and indexed in LIPECS. The percentage of published theses in biomedical journals at this university is comparable with others coming from developed countries.