Peripheral Nervous System Manifestations Associated with COVID-19.

PURPOSE OF REVIEW: The present review discusses the peripheral nervous system (PNS) manifestations associated with coronavirus disease 2019 (COVID-19). RECENT FINDINGS: Nerve pain and skeletal muscle injury, Guillain-Barré syndrome, cranial polyneuritis, neuromuscular junction disorders, neuro-ophthalmological disorders, neurosensory hearing loss, and dysautonomia have been reported as PNS manifestations in patients with COVID-19. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes COVID-19. COVID-19 has shown syndromic complexity. Not only does SARS-CoV-2 affect the central nervous system but also it involves the PNS. The PNS involvement may be due to dysregulation of the immune system attributable to COVID-19. Here we review the broad spectrum of PNS involvement of COVID-19.

Current Advances in Endovascular Treatment of Intracranial Atherosclerotic Disease and Future Prospective.

OBJECTIVES/BACKGROUND: Medical therapy is the first line of treatment for intracranial atherosclerotic disease (ICAD). Percutaneous transluminal angioplasty and stenting (PTAS) are mainly considered for those patients with severe stenosis and recurrent events despite aggressive medical therapy. In this review, we discuss the application of PTAS as a treatment option for ICAD and its future prospect. MATERIALS AND METHODS: We did the literature review of the key articles and guidelines to elaborate on the role of PTAS in the management of ICAD based on the current data and expert opinion. We searched PubMed, Google Scholar, and Scopus up to August 2020, and included articles published only in the English language. RESULTS: Since the publication of the results from SAMMPRIS and VISSIT trials, stenting is no longer recommended for secondary stroke prevention in patients with symptomatic ICAD. However, recent clinical studies on intracranial stenting for a subgroup of ICAD patients have shown promising results, likely due to better patient selection and continued advancement of endovascular techniques. CONCLUSION: There exists a lack of consensus regarding the best endovascular treatment approach (e.g., angioplasty alone or balloon mounted stent vs. self-expanding stent with or without prior angioplasty) or management of in-stent restenosis. Another area of clinical controversy relates to the ideal use and duration of antiplatelet therapy.

Transfemoral Approach to Induce Transient Middle Cerebral Artery Occlusion in Rats: The Use of Commercially Available Endovascular Wires.

BACKGROUND: Animal models of stroke play a crucial role in determining the pathophysiology of stroke progression and assessment of any new therapeutic approaches. Transient middle cerebral artery occlusion (tMCAo) in rodent models are the most common site-specific type of ischemia because of their relevance to the clinical setting. Compared with the intraluminal filament technique for inducing tMCAo, the transfemoral approach using endovascular wires is relatively a new technique METHODS: Here we present the use of commercially available wires used for neuro-endovascular surgical procedures to induce tMCAo in rats via a transfemoral approach. We used male Wistar rats in four groups to assess the effect of occlusion time (1 vs. 2 hours) and the wire type (PT2 TM 0.014″ vs. TransendTM EX, 0.014″, Boston Scientific, MA, USA). Infarct volume, edema, neurological deficits, and pro-inflammatory/anti-inflammatory blood biomarkers were used as outcome measures. RESULTS: We observed a significant effect of the wire type on the infarct volume (p value = 0.0096) where infarcts were slightly larger in the PT2 wiregroups. However, the occlusion time had no significant effect on infarct volume, even though the interaction between wire-type * occlusion-time was significant (p value = 0.024). Also, the amount of edema and blood pro-inflammatory/anti-inflammatory biomarkers were not statistically different among the wire-type and occlusion-time groups. CONCLUSIONS: The choice of appropriate endovascular wire should probably be the focus of the study design instead of the occlusion time when planning an experiment. The transfemoral approach using endovascular wires for inducing tMCAo in rats provides a more consistent outcome with fewer complications compared with suture filament models.

Exploration of Multiparameter Hematoma 3D Image Analysis for Predicting Outcome After Intracerebral Hemorrhage.

BACKGROUND: Rapid diagnosis and proper management of intracerebral hemorrhage (ICH) play a crucial role in the outcome. Prediction of the outcome with a high degree of accuracy based on admission data including imaging information can potentially influence clinical decision-making practice. METHODS: We conducted a retrospective multicenter study of consecutive ICH patients admitted between 2012-2017. Medical history, admission data, and initial head computed tomography (CT) scan were collected. CT scans were semiautomatically segmented for hematoma volume, hematoma density histograms, and sphericity index (SI). Discharge unfavorable outcomes were defined as death or severe disability (modified Rankin Scores 4-6). We compared (1) hematoma volume alone; (2) multiparameter imaging data including hematoma volume, location, density heterogeneity, SI, and midline shift; and (3) multiparameter imaging data with clinical information available on admission for ICH outcome prediction. Multivariate analysis and predictive modeling were used to determine the significance of hematoma characteristics on the outcome. RESULTS: We included 430 subjects in this analysis. Models using automated hematoma segmentation showed incremental predictive accuracies for in-hospital mortality using hematoma volume only: area under the curve (AUC): 0.85 [0.76-0.93], multiparameter imaging data (hematoma volume, location, CT density, SI, and midline shift): AUC: 0.91 [0.86-0.97], and multiparameter imaging data plus clinical information on admission (Glasgow Coma Scale (GCS) score and age): AUC: 0.94 [0.89-0.99]. Similarly, severe disability predictive accuracy varied from AUC: 0.84 [0.76-0.93] for volume-only model to AUC: 0.88 [0.80-0.95] for imaging data models and AUC: 0.92 [0.86-0.98] for imaging plus clinical predictors. CONCLUSIONS: Multiparameter models combining imaging and admission clinical data show high accuracy for predicting discharge unfavorable outcome after ICH.

Blood Pressure Variability Predicts Poor In-Hospital Outcome in Spontaneous Intracerebral Hemorrhage.

Background and Purpose- There is increasing evidence that higher systolic blood pressure variability (SBPV) may be associated with poor outcome in patients with intracerebral hemorrhage (ICH). We explored the association between SBPV and in-hospital ICH outcome. Methods- We collected 10-years of consecutive data of spontaneous ICH patients at 2 healthcare systems. Demographics, medical history, laboratory tests, computed tomography scan data, in-hospital treatments, and neurological and functional assessments were recorded. Blood pressure recordings were extracted up to 24 hours postadmission. SBPV was measured using SD, coefficient of variation, successive variation (SV), range and 1 novel index termed functional SV. The effects of SBPV on the functional outcome at discharge were evaluated by multivariate logistic and ordinal regression analyses for dichotomous and trichotomous modified Rankin Scale categorizations, respectively. In secondary analyses, associations between SBPV, history of hypertension, and hematoma expansion were explored. Results- The analysis included 762 subjects. All 5 SBPV indices were significantly associated with the probability of unfavorable outcome (modified Rankin Scale score, 4-6) in logistic models. In ordinal models, SD, coefficient of variation, range, and functional SV were found to have a significant effect on the probabilities of poor (modified Rankin Scale score, 3-4) and severe/death (modified Rankin Scale score, 5-6) outcomes. Normotensive patients had significantly lower mean SBPV compared with the untreated-hypertension cohort for all SBPV indices and compared with treated-hypertension patients for 3 out of 5 SBPV indices. Lower mean SBPV of treated-hypertension subjects compared with untreated-hypertension subjects was only detected in the SV and functional SV indices (P=0.045). None of the SBPV indices were significantly associated with the probability of hematoma expansion. Conclusions- Higher SBPV in the first 24 hours of admission was associated with unfavorable in-hospital outcome among ICH patients. Further prospective studies are warranted to understand any cause-effect relationship and whether controlling for SBPV may improve the ICH outcome.

The Role of Serum Calcium Level in Intracerebral Hemorrhage Hematoma Expansion: Is There Any?

Spontaneous intracerebral hemorrhage (ICH) is a devastating form of stroke, with a high rate of mortality and morbidity. Even with the best current medical or surgical interventions, outcomes remain poor. The location and initial hematoma volume are strong predictors of mortality. Hematoma expansion (HE) is a further marker of poor prognosis that may be at least partly preventable. Several risk factors for HE have been identified, including baseline ICH volume, anticoagulation, and computed tomography angiography spot signs. Recent studies have shown the correlation of serum calcium (Ca++) levels on admission with HE. Low serum Ca++ level has been associated with larger hematoma volume at the time of presentation, HE, and worse outcome. Although the causal and mechanistic links between low serum Ca++ level and HE are not well understood, several mechanisms have been proposed including coagulopathy, platelet dysfunction, and higher blood pressure (BP) in the context of low serum Ca++ level. However, low serum Ca++ level might be only a biomarker of the adaptive response due to acute inflammatory response following acute ICH. The purpose of the current review is to discuss the evidence regarding the possible role of low serum Ca++ level on HE in acute ICH.

Solid-phase microextraction of phthalate esters by a new coating based on a thermally stable polypyrrole/graphene oxide composite.

A novel polypyrole/graphene oxide coating was made by the electrochemical polymerization of pyrrole in the presence of sodium dodecyl sulfate and graphene oxide on a platinum wire. The prepared fiber has shown a good thermal stability up to 300°C. The fiber was applied to the direct solid-phase microextraction and gas chromatographic analysis of four phthalate esters. The effect of four parameters on gas chromatography peak area including extraction temperature, extraction time, injection temperature, and ionic strength were investigated. Under the optimized conditions, the detection limits were between 0.042 and 0.26 µg/L. The intraday and interday relative standard deviations obtained at 55 µg/L, using a single fiber, were 8.2-16% and 17.3-25.6%, respectively. The method was successfully applied to the analysis of phthalate esters in two real samples of boiling water in cheap disposable clear plastic drinking cups showing recoveries from 83 to 120%.

Curcumin-Melamine For Solid-Phase Microextraction of Volatile Organic Compounds from Aqueous Samples.

The hybrid coating of curcumin and melamine was prepared by a simple electrochemical method. Some physical and chemical properties of the fiber were studied by several methods such as FT-IR, scanning electron microscopy and X-ray fluorescence spectroscopy. The fiber was stable at the inlet of a gas chromatograph at temperatures up to 280°C. The fiber has been used for the extraction of ethylbenzene, toluene and xylenes (ETX). Some parameters of headspace solid-phase microextraction, including extraction time, temperature and salt amount, were optimized. Under the optimized situation, the detection limits were 0.15-0.21 µg L -1 and the linear ranges were within the range of 0.5-1,000 µg L-1 (r2 ≥ 0.99). The intra-day and inter-day relative standard deviations were 10.2-13.7 and 13.0-15.6%, respectively, at a concentration level of 10 µg L-1 from each compound by applying a single fiber. The method was used to successfully analyze wastewater and pool water samples.

A conceptual model for empowering faculty members of third-generation universities of medical sciences.

Background and objectives: Despite the crucial role of university staff and especially faculty members in moving towards third-generation universities, as well as the necessity of staff empowerment, only a handful of studies have been carried out on staff (especially faculty member) empowerment. This study designed a conceptual model for empowering faculty members of universities of medical sciences and facilitating transition to third-generation universities. Methods: The grounded theory approach was adopted to conduct this qualitative study. A total of 11 faculty members with entrepreneurial experience were selected as the sample using purposive sampling. The data were collected using semi-structured interviews, and the obtained data were entered into qualitative software (MAXQDA 10) for analysis. Results: The concepts identified in the coding process were summarized and classified into five groups and seven main categories. Then the conceptual model was designed with a set of causal factors (including structure of the education system, recruitment, training, and investment), structure and context factors (including structure and relationship), intervening factors (including promotion and ranking systems in universities and lack of mutual trust between industry and university), a core category (characteristics of capable faculty members), and an outcome (third-generation university). Finally, the conceptual model was developed to empower faculty members of third-generation universities of medical sciences. Conclusions: Based on the designed conceptual model, the most important issue in moving towards third-generation universities is "characteristics of capable faculty members." The present findings will help policy makers better understand the major factors affecting faculty member empowerment.

Application of numerical simulation to solid phase-microextraction for decreasing of extraction time of pyrene and phthalate esters on solid coatings.

Reynolds-Averaged Navier-Stokes (RANS) approach with the k-ε closure model is employed for the first time to simulate direct Solid-Phase Micro-Extraction (SPME) computationally. Simulations are performed by using COMSOL Multiphysics in order to examine methods to decrease the extraction time. Experiments are also conducted to support data obtained from the numerical framework. Di-n-Butyl Phthalate (DNBP) and etched steel wire are chosen as the analyte and the adsorbent, respectively. Stirring rate, fiber's location, stirrer magnet's size, and the method of sample rotation are examined to decrease the extraction time. In addition, the effects of adding a baffle to the vial and implementing a periodic function for stirring the sample are studied. Increasing the stirring rate from 700 to 3000 rpm reduces the extraction time from 50 to 36 minutes. Present results suggest that changing the fiber's location and implementing a periodic stirring pattern significantly decrease the extraction time of SPME. The optimum fiber's location is found at 7.5 mm far from the vial's center, which leads to a 51% decrease in the extraction time. Furthermore, using a periodic stirring pattern results in a 60% decrease in the extraction time compared to the traditional uniform stirring pattern. To examine the robustness and reliability of the presented framework, two additional analytes, namely pyrene and Dioctyl phthalate (DOP), are chosen with one additional fiber, Al2O3. In this regard, the additional materials are used in the framework to investigate the effects of fiber's location and stirring pattern. By optimizing the fiber's location, the extraction time is reduced by 36% and 40% for SPME of pyrene and DOP, respectively. On the other hand, by using a periodic stirring pattern, the extraction time is reduced by 42% and 46% for SPME of pyrene and DOP, respectively.

Correlation of Deceased Donor Factors to Postreperfusion Severe Hyperglycemia in Adult Patients Undergoing Liver Transplant.

OBJECTIVES: In this study, our objective was to identify perioperative factors associated with postreperfusion severe hyperglycemia, with a particular focus on deceased donor factors. MATERIALS AND METHODS: Perioperative data from 100 patients without diabetes who were undergoing liver transplant from deceased donors were reviewed. Mean blood glucose levels were calculated at each liver transplant surgical phase, with a cutoff level of 12.7 mmol/L (230 mg/dL) during the neo-hepatic phase defined as postreperfusion severe hyperglycemia. Patients were divided into those with and without postreperfusion severe hyperglycemia. Selected perioperative variables were compared between the 2 groups. RESULTS: Of 100 patients, 55 developed postreperfusion severe hyperglycemia. Among donor variables, a statistically significant difference between groups was only shown for graft-to-recipient liver weight ratio (P < .001). With regard to preoperative recipient variables, the 2 groups showed a significant difference in mean age (P = .001). Patients in the postreperfusion severe hyperglycemia group required significantly more packed red blood cell transfusions (P = .002), sodium bicarbonate (P = .054), and vasopressors (P = .002) during the operation. Moreover, in terms of laboratory findings, although the last arterial pH was acceptable in both groups, a last lower arterial pH was observed in patients with postreperfusion severe hyperglycemia (P = .011). Higher mean blood glucose levels were detected in the postreperfusion hyperglycemia group during the preanhepatic and anhepatic phases (P = .024, P = .001, respectively). CONCLUSIONS: In patients undergoing liver transplant, incidence of postreperfusion severe hyperglycemia was influenced by graft-to-recipient liver weight ratio. Furthermore, postreperfusion severe hyperglycemia was associated with intraoperative clinical and laboratory disturbances in liver transplant recipients.

Impact of systemic inflammatory response syndrome on acute ischemic stroke patients treated with mechanical thrombectomy.

AIM: Systemic inflammatory response syndrome (SIRS) has been associated with poor outcomes after acute ischemic stroke (AIS). The primary goal of this study was to determine whether SIRS status on admission correlated with functional outcomes in AIS treated with mechanical thrombectomy (MT). METHODS: Consecutive patients from September 2015 to April 2019 were retrospectively reviewed for SIRS on admission. SIRS was defined as the presence of ≥2 of the following: temperature < 36 °C or > 38 °C, heart rate > 90, respiratory rate > 20, and white blood cell count <4000/mm or > 12,000 mm. RESULTS: Of 202 patients, 188 met inclusion criteria. 49 patients (26%) had evidence of SIRS. Neither basic patient demographics nor standard stroke risk factors predicted the development of SIRS. However, presentation with SIRS was correlated with higher rates of death (odds ratio [OR], 2.6; 95% confidence interval [CI], 1.2-5.5) as well as lower rates of favorable functional outcomes at discharge (OR, 0.09; 95% CI, 0.02-0.40) and 3-month follow up (OR 0.12; 95% CI 0.03-0.43). These results remained significant even after adjustment for age, sex, baseline NIHSS, recanalization status, and prior co-morbidities. CONCLUSION: In our sample population, SIRS was associated with worse outcomes and higher rates of mortality in AIS patients treated with MT. Recognition of key risk factors can provide better prognostication and possible future therapeutic targets.

Blood pressure variability and outcome after acute intracerebral hemorrhage.

Intracerebral hemorrhage (ICH) is life threatening neurologic event that results in significant rate of morbidity and mortality. Unfortunately, several randomized clinical trials aiming at limiting the hematoma expansion (HE) in the acute phase of ICH have not shown significant effects in improving the functional outcomes. Blood pressure variability (BPV) is common following ICH. High BPs have been associated with increased risk of bleeding and HE. Conversely, recurrent sudden decrease in BP promote perihematomal ischemia. However, it is still not clear weather BPV causes adverse prognosis following ICH or large ICHs cause fluctuations in BP. In the current review, we will discuss the mechanistic pathophysiology of BPV and the evidence regarding the role of BPV on the ICH outcomes.

Blood pressure management after mechanical thrombectomy in stroke patients.

Endovascular treatment of acute ischemic stroke (AIS) and mechanical thrombectomy (MT) is proven as a safe and effective novel treatment for emergent large vessel occlusion in the anterior cerebral circulation. However, there are still many unanswered questions on peri and post-procedural management including blood pressure (BP) control. The current guidelines recommend maintaining BP <180/105 mmHg in the first 24 h after MT. However, recent studies suggest that maintaining BP levels at lower levels in the first 24 h after successful revascularization have been associated with favorable functional outcome, reduced mortality rate, and hemorrhagic complications. Not only absolute BP but also its variation in the first 24 h after MT have been associated with neurological outcomes. Evidence on the effect of BP variability (BPV) after MT in AIS even though limited, it does indicate the association of the higher BPV in the first 24 h after MT and poor functional outcomes in AIS. In this review, we will discuss the current literature on BP management in the first 24 h after MT and the impact of BPV in the first 24 h after MT.

The effect of hydro-alcoholic extract of Ceratonia Silique L. on spermatogenesis index in rats treated with cyclophosphamide: An experimental study.

BACKGROUND: The aim of this study was to investigate the antioxidant effects of Ceratonia extract on improving the toxicity induced by cyclophosphamide (CP) on spermatogenesis. Materials and Methods: 54 male Wistar rats (4 months old) weighing 200-250 gr were randomly divided into 6 groups (n = 9/each). OBJECTIVE: "group 1 (control) underwent the normal diet and water; group 2 (sham) received 2 ml/day normal saline; group 3 (positive control) received 300 mg/kg/day Ceratonia extract; group 4 (Ceratonia + CP) received Ceratonia extract (300 mg/kg/day) + 5 mg/kg/day CP (Endoxan, baxter oncology gmbh, Germany) after 4 hr; group 5 (CP) received 5 mg/kg/day CP + normal saline 4 hr after it; and group 6 (CP + Ceratonia) received Ceratonia extract (300 mg/kg/day) 4 hr after 5 mg/kg/day CP." 24 hr after the last gavage, heart blood sampling was performed to measure the levels of malondialdehyde (MDA), ferric reducing antioxidant power, testosterone, luteinizing hormone, and follicle-stimulating hormone. The left caudal epididymis was cut in the Ham's F10 and the released spermatozoa were used to analyze sperm parameters. The histology of the right testes was studied using stereological techniques and the left testes were used to measure the level of tissue MDA and ferric reducing antioxidant power. RESULTS: A significant increase in the mean level of MDA (p = 0.013) was seen in the CP compared to the control group. Sperm motility (p = 0.001) and count (p = 0.002), serum and tissue total antioxidant (p ≤ 0.001) and serum testosterone levels (p = 0.019) decreased in the CP compared to the control group. Ceratonia extract could significantly prevent the adverse effects of CP on sperm motility (p < 0.001), the mean levels of tissue MDA (p = 0.018), serum total antioxidant (p = 0.045), and testosterone (p < 0.001). CONCLUSION: The Ceratonia extract can modify the reproductive toxicity of CP in rat due to the presence of antioxidant compounds.

Comparison of First-Pass Efficacy Among Four Mechanical Thrombectomy Techniques: A Single-Center Experience.

BACKGROUND: First-pass efficacy (FPE) is an established marker of technical and clinical efficacy among mechanical thrombectomy (MT) techniques. It is unclear what the optimal approach is in achieving FPE. We present a single-center experience comparing rates of FPE among 2 MT techniques and evaluate the potential predictors of FPE among other outcomes. METHODS: A single-center retrospective analysis was carried out of patients with consecutive large-vessel occlusion strokes (LVOS) of anterior circulation from September 2015 to April 2019 who underwent MT and for whom data were available on the status of FPE. Four MT techniques were identified: ADAPT (a direct first-pass aspiration), SrADAPT (stent retriever with aspiration), SRBG (stent retriever with balloon guide catheter), and STRAP (stent retriever-aspiration and proximal flow arrest). The primary outcome was FPE and secondary outcomes included the rate of successful reperfusion. RESULTS: Among 226 patients with LVOS of the anterior circulation who underwent MT, data were available for 164 on FPE for the 4 MT techniques. SRBG was the most prevalent technique. No significant difference was found in rates of FPE among the 4 MT techniques (P = 0.332). No independent predictors of FPE were identified on multivariable analysis. STRAP had the highest rate of successful reperfusion compared with the other techniques (P = 0.049) and was the only independent predictor of that outcome (P = 0.027). CONCLUSIONS: Among patients with LVOS of the anterior circulation, the rate of FPE did not differ among the 4 MT techniques. There were no predictors of FPE among the studied variables. STRAP was the only predictor of successful reperfusion.

Serum magnesium level and hematoma expansion in patients with intracerebral hemorrhage.

Spontaneous intracerebral hemorrhage (ICH) is a devastating subtype of stroke that results in significant rates of mortality and morbidities. The initial hematoma volume, hematoma expansion (HE), blood pressure (BP), and coagulopathy are considered strong predictors of clinical outcomes and mortality. Low serum magnesium (Mg++) levels have been shown to be associated with larger initial hematoma and greater HE. Coagulopathy, platelet dysfunction, high BP, and increased inflammatory response might form the mechanistic link between low serum Mg++ levels, larger hematoma size and greater HE. However, randomized clinical trials administering intravenous Mg++ have shown no benefit over placebo in ICH patients. The confounding effect of hypocalcemia and a delay in Mg++ trafficking across the blood-brain barrier might explain the futile results for intravenous Mg++ therapy. In the current review, we will discuss the evidence regarding the possible role of low serum Mg++ level on HE in acute ICH.

Untreated hypertension as predictor of in-hospital mortality in intracerebral hemorrhage: A multi-center study.

PURPOSE: Hypertension is a significant risk factor for intracerebral hemorrhage (ICH). The importance of managing blood pressure to reduce the risk of ICH has been recognized. However, few studies have focused on ICH outcomes due to untreated hypertension. MATERIALS AND METHODS: We conducted a 5-year, retrospective, multicenter study of 490 consecutive ICH patients with histories of untreated-hypertension (n=56), treated-hypertension (n=314), and normotension (n=120). Demographics, symptom onset, vital signs, laboratory tests, and CT imaging were documented alongside in-hospital treatments, complications, and length of stay. RESULTS: Untreated-hypertension subjects were found to be significantly younger than treated-hypertension. They were found to have lower rates of anticoagulant use (p<0.01), antiplatelet use (p<0.01), and hyperlipidemia (p<0.01) than subjects with treated-hypertension. In a multivariate model, untreated-hypertension, age ≥65years, ≥3 outpatient antihypertensive medications, and hematoma volumes ≥30ml were all associated with significantly increased in-hospital mortality. In contrast, mortality was lower in patients receiving ≥3 antihypertensive medications while in-hospital. CONCLUSIONS: Subjects with untreated-hypertension were younger and had fewer comorbidities when compared with treated-hypertension and were similar when compared to normotensive individuals. Once demographic and in-hospital factors were accounted for, untreated-hypertension subjects demonstrated significantly increased in-hospital mortality following ICH when compared with normotensive individuals.

Simulating soil organic carbon stock as affected by land cover change and climate change, Hyrcanian forests (northern Iran).

Soil organic carbon (SOC) contains a considerable portion of the world's terrestrial carbon stock, and is affected by changes in land cover and climate. SOC modeling is a useful approach to assess the impact of land use, land use change and climate change on carbon (C) sequestration. This study aimed to: (i) test the performance of RothC model using data measured from different land covers in Hyrcanian forests (northern Iran); and (ii) predict changes in SOC under different climate change scenarios that may occur in the future. The following land covers were considered: Quercus castaneifolia (QC), Acer velutinum (AV), Alnus subcordata (AS), Cupressus sempervirens (CS) plantations and a natural forest (NF). For assessment of future climate change projections the Fifth Assessment IPCC report was used. These projections were generated with nine Global Climate Models (GCMs), for two Representative Concentration Pathways (RCPs) leading to very low and high greenhouse gases concentration levels (RCP 2.6 and RCP 8.5 respectively), and for four 20year-periods up to 2099 (2030s, 2050s, 2070s and 2090s). Simulated values of SOC correlated well with measured data (R2=0.64 to 0.91) indicating a good efficiency of the RothC model. Our results showed an overall decrease in SOC stocks by 2099 under all land covers and climate change scenarios, but the extent of the decrease varied with the climate models, the emissions scenarios, time periods and land covers. Acer velutinum plantation was the most sensitive land cover to future climate change (range of decrease 8.34-21.83tCha-1). Results suggest that modeling techniques can be effectively applied for evaluating SOC stocks, allowing the identification of current patterns in the soil and the prediction of future conditions.

The Effect of l-Arginine on Dural Healing After Experimentally Induced Dural Defect in a Rat Model.

BACKGROUND: Incomplete repair of the dura mater may result in numerous complications such as cerebrospinal fluid leakage and meningitis. For this reason, accurate repair of the dura mater is essential. In this study, the effect of systemic and local supplementation of l-arginine on dural healing was evaluated. METHODS: Thirty male Wistar rats were used and divided into control, local, and systemic l-arginine groups, with 10 rats in each. In each group, a 5-mm experimental incision was made at the lumbar segment of the dura mater and cerebrospinal fluid leakage was induced. Each group was divided into 2 subgroups and at the end of the first and sixth weeks, the rats were killed and the damaged segments of the dura were separated, histologically evaluated and the dural healing indicators including cell types, granulation tissue formation, collagen deposit, and vascularization were compared between groups. RESULTS: The systematic supplementation of l-arginine showed a significant effect in dural healing compared with the control group. After the first week, granulation formation increased considerably (P < 0.031), and after 6 weeks, collagen deposition and neovascularization were significantly different compared with the control group (P < 0.030; P < 0.009). In comparison between different groups at the end of the first and sixth weeks, maximum changes in healing indicators were observed in the systemic group and the least variations were related to the control group. CONCLUSIONS: The systemic supplementation of l-arginine may accelerate dural healing by increasing the level of granulation tissue formation, collagen deposition, and vascularization.