Age specific reference intervals for plasma biomarkers of neurodegeneration and neurotrauma in a Canadian population

INTRODUCTION

In this study, we aimed to create reference intervals (RI) using a large Canadian population-based cohort, for plasma protein biomarkers with potential utility to screen, diagnosis, prognosticate and manage a variety of neurological diseases and disorders. RIs were generated for: the ratio of amyloid beta 42 over 40 (Aβ42/40), phosphorylated tau-181 (p-tau-181), neurofilament light (NfL), and glial fibrillary acidic protein (GFAP).

METHODS

900 plasma specimens from male and female participants aged 3-79 years old were obtained from the Statistics Canada Biobank, which holds specimens from the Canadian Health Measures Survey. Analysis of Aβ42/40, p-tau-181, NfL and GFAP was performed on the Quanterix Simoa HD-X analyzer using the Neurology 4-plex E and p-tau-181 assays. Discrete RIs were produced according to Clinical Laboratory Standards Institute guidelines (EP28-A3c). Continuous RIs were created using quantile regression.

RESULTS

For discrete RIs, significant age partitions were determined for each biomarker. No significant sex partitions were found. The following ranges and age partitions were determined: Aβ42/40: 3-<55y = 0.053-0.098, 55-<80y = 0.040-0.090; p-tau-181: 3-<12y = 1.4-5.6 pg/ml, 12-<60y = 0.8-3.1 pg/ml, 60-<80y = 0.9-4.0 pg/ml; NfL: 3-<40y = 2.6-11.3 pg/ml, 40-<60y = 4.6-17.7 pg/ml, 60-<80y = 8.1-47.1 pg/ml; GFAP; 3-<10y = 47.0-226 pg/ml, 10-<60y = 21.2-91.9 pg/ml, 60-<80y = 40.7-228 pg/ml. Continuous RIs produced smooth centile curves across the age range, from which point estimates for each year of age were calculated.

CONCLUSIONS

Discrete and continuous RIs for neurological plasma biomarkers will help refine normative cut-offs across the lifespan and improve the precision of interpretating biomarker levels. Continuous RIs are recommended for use in age groups, such as pediatrics and older adults, that experience rapid concentration changes by age.

Use of Biostatistical Models to Manage Replicate Error in Concussion Biomarker Research

Importance

Advancing research on fluid biomarkers associated with sport-related concussion (SRC) highlights the importance of detecting low concentrations using ultrasensitive platforms. However, common statistical practices may overlook replicate errors and specimen exclusion, emphasizing the need to explore robust modeling approaches that consider all available replicate data for comprehensive understanding of sample variation and statistical inferences.

Objective

To evaluate the impact of replicate error and different biostatistical modeling approaches on SRC biomarker interpretation.

Design, Setting, and Participants

This cross-sectional study within the Surveillance in High Schools to Reduce the Risk of Concussions and Their Consequences study used data from healthy youth athletes (ages 11-18 years) collected from 3 sites across Canada between September 2019 and November 2021. Data were analyzed from November 2022 to February 2023.

Exposures

Demographic variables included age, sex, and self-reported history of previous concussion.

Main Outcomes and Measures

Outcomes of interest were preinjury plasma glial fibrillary acidic protein (GFAP), ubiquitin C-terminal hydrolase-L1 (UCH-L1), neurofilament-light (NFL), total tau (t-tau) and phosphorylated-tau-181 (p-tau-181) assayed in duplicate. Bland-Altman analysis determined the 95% limits of agreement (LOAs) for each biomarker. The impact of replicate error was explored using 3 biostatistical modeling approaches assessing the associations of age, sex, and previous concussion on biomarker concentrations: multilevel regression using all available replicate data, single-level regression using the means of replicate data, and single-level regression with replicate means, excluding specimens demonstrating more than 20% coefficient variation (CV).

Results

The sample included 149 healthy youth athletes (78 [52%] male; mean [SD] age, 15.74 [1.41] years; 51 participants [34%] reporting ≥1 previous concussions). Wide 95% LOAs were observed for GFAP (-17.74 to 18.20 pg/mL), UCH-L1 (-13.80 to 14.77 pg/mL), and t-tau (65.27% to 150.03%). GFAP and UCH-L1 were significantly associated with sex in multilevel regression (GFAP: effect size, 15.65%; β = -0.17; 95% CI, -0.30 to -0.04]; P = .02; UCH-L1: effect size, 17.24%; β = -0.19; 95% CI, -0.36 to -0.02]; P = .03) and single-level regression using the means of replicate data (GFAP: effect size, 15.56%; β = -0.17; 95% CI, -0.30 to -0.03]; P = .02; UCH-L1: effect size, 18.02%; β = -0.20; 95% CI, -0.37 to -0.03]; P = .02); however, there was no association for UCH-L1 after excluding specimens demonstrating more than 20% CV. Excluding specimens demonstrating more than 20% CV resulted in decreased differences associated with sex in GFAP (effect size, 12.29%; β = -0.14; 95% CI, -0.273 to -0.004]; P = .04) and increased sex differences in UCH-L1 (effect size, 23.59%; β = -0.27; 95% CI, -0.55 to 0.01]; P = .06), with the widest 95% CIs (ie, least precision) found in UCH-L1.

Conclusions and Relevance

In this cross-sectional study of healthy youth athletes, varying levels of agreement between SRC biomarker technical replicates suggested that means of measurements may not optimize precision for population values. Multilevel regression modeling demonstrated how incorporating all available biomarker data could capture replicate variation, avoiding challenges associated with means and percentage of CV exclusion thresholds to produce more representative estimates of association.

Characterizing Factors Influencing Baseline Plasma Biomarkers for Sport-Related Concussion in Adolescents

Abstract Developing objective measures to diagnose sport-related concussion (SRC) is a top priority, particularly in the pediatric context, given the vulnerability of the developing brain. While advances in SRC blood biomarkers are being made in adult populations, less data are available for adolescents. Clinical validation of blood biomarkers post-SRC will first require investigation in a healthy uninjured state. Further, rapid pubertal changes during adolescence may implicate possible interactions with circulating sex hormones and the menstrual cycle for females. This cross-sectional study aimed to characterize pre-injury plasma levels of glial fibrillary acidic protein (GFAP), neurofilament light (NF-L), ubiquitin C-terminal hydrolase-L1 (UCH-L1), total tau (T-tau), and phosphorylated tau-181 (P-tau-181), considering previous concussion, age, and sex in healthy adolescent sport participants. Possible associations with menstrual cycle phase and circulating sex hormone levels (i.e., progesterone, estradiol, testosterone) were also explored. Pre-injury blood samples were obtained from 149 healthy adolescents (48% female, ages 11-18) participating in a larger Surveillance in High Schools and Community Sports to Reduce Concussions and their Consequences (SHRed Concussions) multi-site longitudinal cohort study. Main outcomes were natural log (ln) transformed plasma GFAP, NF-L, UCH-L1, T-tau, and P-tau-181 concentrations, quantified on the Quanterix Simoa HD-X platform. Mixed-effects multi-variable linear regression was used to assess associations between biomarkers and self-reported previous concussion (yes/no), age (years), sex (male/female), objectively determined menstrual cycle phase (follicular/luteal), plasma progesterone, estradiol, and testosterone. Males had 19.8% lower UCH-L1 (β = -0.221, 95% confidence interval [CI; -0.396, -0.046]), 18.9% lower GFAP (β = -0.210, 95% CI [-0.352, -0.068]), and 21.8% higher P-tau-181 (β = 0.197, 95% CI [0.048, 0.346]) compared with females, adjusting for age and previous concussion. GFAP decreased 9.5% with each 1-year increase in age, adjusting for previous concussion and sex (β = -0.100, 95% CI [-0.152, -0.049]). No biomarkers were associated with a history of previous concussion. Exploratory investigations found no associations between biomarkers and menstrual cycle phase. Females displayed an age-adjusted negative association between T-tau and progesterone (β = -0.010, 95% CI [-0.018, -0.002]), whereas males had a negative age-adjusted association between UCH-L1 and testosterone (β = -0.020, 95% CI [-0.037, -0.002]). As such, age- and sex-specific reference intervals may be warranted for pediatric athlete populations prior to clinical validation of blood biomarkers for SRC. Additionally, hormonal associations highlight the need to consider puberty and development in adolescent studies. Overall, findings suggest these biomarkers are resilient to a history of previous concussion and menstrual cycle phase, supporting continued investigation in adolescent SRC.

Influence of sexually transmitted infections on the cervical cytological abnormalities among Iranian women: A cross-sectional study

BACKGROUND

Sexually transmitted infections (STIs) are one of the world's most severe health challenges. The existence of STIs such as human papillomavirus (HPV) might cause cervical cell changes leading to cervical cancer.

OBJECTIVE

This study aims to assess the association of STIs with cervical cytological abnormalities and genital warts among women in northeastern Iran.

MATERIALS AND METHODS

This cross-sectional study was carried out on 190 women referred to the central laboratory of Academic Center for Education, Culture, and Research, Mashhad, Iran from March to July 2022. The presence of genital infections caused by Chlamydia trachomatis, Neisseria gonorrhoeae, Mycoplasma genitalium, and Herpes simplex viruses (1 and 2) were assessed using the real-time polymerase chain reaction method. HPV genital infection was detected based on the principles of reverse hybridization, and cellular changes in the cervix were examined by the liquid-based cytology technique.

RESULTS

The mean age of participants was 35.33 ± 8.9 yr. 34 different HPV genotypes were detected in all HPV-positive cases, and the most common genotype was low-risk HPV6. No significant association was found between STIs and cervical cytology abnormalities. The prevalence rates of sexually transmitted pathogens among HPV-positive and HPV-negative individuals were 10.9 and 1.6%, respectively. The frequency of genital warts was significantly higher in cases with multiple infections of high- and low-risk HPV genotypes.

CONCLUSION

High percentages of the participants with non-HPV STIs and HPV infection had normal cervical cytology. It is advised to use STIs and HPV diagnostic tests along with cytology examinations for cervical cancer screening.

Evaluation of IL-3, IL-5, and IL-6 concentration in the follicular fluid of women with endometriosis: A cross-sectional study

Background

Endometriosis is associated with abnormal immunologic responses and combined inflammatory and anti-inflammatory conditions.

Objective

This study aims to investigate follicular fluid (FF) concentration of interleukin (IL)-3, IL-5, and IL-6 in women with and without endometriosis.

Materials and Methods

In this cross-sectionalstudy 68 women who were referred to the in vitro fertilization center of Imam Reza hospital in Mashhad during 2018 were selected randomly. Leaves of cytokines in the FF samples were evaluated in the endometriosis and the control group (n = 34/each). The diagnostic accuracy of cytokines and clinical characteristics were evaluated.

Results

IL-3 and IL-6 were significantly changed in the FF of the women with endometriosis compared with the control group (p = 0.04, and p < 0.01, respectively), and the mean concentration of IL-5 in the endometriosis group was lower than in the control group (p = 0.5), but this was not significant. There were significant differences in the menstrual cycle, dyspareunia, and dysmenorrhea between the groups (p < 0.01, p = 0.04, and p = 0.02, respectively). The diagnostic accuracy of IL-3 and IL-6 in the FF was low, with the area under the curve of 0.614 and 0.645, respectively.

Conclusion

Although none of the cytokines had a predictive value for endometriosis, the decreased levels of IL-3 and increased levels of IL-6 in the FF samples of women with endometriosis, and risk factors, including irregular menstrual cycle, dyspareunia, and dysmenorrhea, could be associated with the pathogenesis of this painful disease.

On the Distortion Value of Elections with Abstention

In Spatial Voting Theory, distortion is a measure of how good the winner is. It has been proved that no deterministic voting mechanism can guarantee a distortion better than 3, even for simple metrics such as a line. In this study, we wish to answer the following question: how does the distortion value change if we allow less motivated agents to abstain from the election? We consider an election with two candidates and suggest an abstention model, which is a general form of the abstention model proposed by Kirchgässner. Our results characterize the distortion ¨ value and provide a rather complete picture of the model.

Fair Allocation of Indivisible Goods to Asymmetric Agents

We study fair allocation of indivisible goods to agents with unequal entitlements. Fair allocation has been the subject of many studies in both divisible and indivisible settings. Our emphasis is on the case where the goods are indivisible and agents have unequal entitlements. This problem is a generalization of the work by Procaccia and Wang (2014) wherein the agents are assumed to be symmetric with respect to their entitlements. Although Procaccia and Wang show an almost fair (constant approximation) allocation exists in their setting, our main result is in sharp contrast to their observation. We show that, in some cases with n agents, no allocation can guarantee better than 1/n approximation of a fair allocation when the entitlements are not necessarily equal. Furthermore, we devise a simple algorithm that ensures a 1/n approximation guarantee. Our second result is for a restricted version of the problem where the valuation of every agent for each good is bounded by the total value he wishes to receive in a fair allocation. Although this assumption might seem without loss of generality, we show it enables us to find a 1/2 approximation fair allocation via a greedy algorithm. Finally, we run some experiments on real-world data and show that, in practice, a fair allocation is likely to exist. We also support our experiments by showing positive results for two stochastic variants of the problem, namely stochastic agents and stochastic items.

Exophytic glioma of the medulla: presentation, management and outcome

OBJECTIVE

Exophytic gliomas of the medulla are rare childhood tumors that mostly are pilocytic astrocytomas. Here we report our experience in 11 -children with this rare tumor.

METHODS

A retrospective study was performed using the records of children with exophytic gliomas of the medulla at Children's Hospital Medical Center in Tehran, Iran, from 2002 through 2013. The general, clinical, and radiological data and follow-up of all patients were reviewed.

RESULTS

The patients mostly were male aged from 11 months to 7 years. Swallowing problems, failure to thrive and nausea and vomiting were the most common symptoms. The time span between the onset of symptoms and the diagnosis was 2-24 months. Gross total resection of tumor was possible in 8 patients. Most tumors were pilocytic astrocytomas. Patients were followed for 2 months to 11 years (mean = 3.6 years). There was no intraoperative mortality. Recurrence occurred in 1 child with fibrillary astrocytoma.

CONCLUSION

Gross total resection of symptomatic dorsal exophytic medullary glioma is recommended. Most tumors are pilocytic astrocytomas. The attachment of these tumors to important brainstem structures usually inhibits total resection. Electrophysiological monitoring of sensorimotor pathways and cranial nerves can be helpful to preserve surrounding neural tissue during tumor resection and to minimize complications. Regular follow-up of patients with clinical examination and brain MRI is mandatory. Repeated surgery, radiation therapy and chemotherapy are suggested in cases with tumor recurrence or progression.

Atypical language lateralization: an fMRI study in patients with cerebral lesions

Differences in the lateralization of language processes between healthy subjects and patients with neurological complaints other than epilepsy have been less documented than those between healthy subjects and epilepsy patients. Moreover, the contribution of factors such as the location and type of lesion in determining interhemispheric shift of language function is poorly understood. Sixty-seven patients who underwent presurgical evaluations at the Medical Imaging Center of the Imam Khomeini University Hospital, Tehran, and the same number of healthy controls, were recruited. The laterality index (LI) of language activation, calculated from two separate functional magnetic resonance imaging tasks, was compared between the patients and the age-/gender-/handedness-matched controls. Chi square testing showed that the percentages of subjects with "typical" and "atypical" language dominance in the patient group were significantly different from the percentages recorded in the matched healthy controls for both tasks (p<0.005). Lesion type, lesion location, lesion hemisphere, presenting symptom and patient gender had no statistically significant effect on the hemispheric LI (p>0.05). In a logistic regression model including all potential determinants of atypical LI, age emerged as the only independent predictor (p<0.05, odds ratio=0.9). Abnormal language lateralization is found in patients with a variety of cerebral lesions and with a diversity of clinical manifestations. In our selected population, symptom duration, lesion hemisphere and anatomical site of the lesion were not found to impact significantly on the development of an abnormal LI while patient age can independently predict the presence of an atypical LI.

Deep sequencing of the oral microbiome reveals signatures of periodontal disease

The oral microbiome, the complex ecosystem of microbes inhabiting the human mouth, harbors several thousands of bacterial types. The proliferation of pathogenic bacteria within the mouth gives rise to periodontitis, an inflammatory disease known to also constitute a risk factor for cardiovascular disease. While much is known about individual species associated with pathogenesis, the system-level mechanisms underlying the transition from health to disease are still poorly understood. Through the sequencing of the 16S rRNA gene and of whole community DNA we provide a glimpse at the global genetic, metabolic, and ecological changes associated with periodontitis in 15 subgingival plaque samples, four from each of two periodontitis patients, and the remaining samples from three healthy individuals. We also demonstrate the power of whole-metagenome sequencing approaches in characterizing the genomes of key players in the oral microbiome, including an unculturable TM7 organism. We reveal the disease microbiome to be enriched in virulence factors, and adapted to a parasitic lifestyle that takes advantage of the disrupted host homeostasis. Furthermore, diseased samples share a common structure that was not found in completely healthy samples, suggesting that the disease state may occupy a narrow region within the space of possible configurations of the oral microbiome. Our pilot study demonstrates the power of high-throughput sequencing as a tool for understanding the role of the oral microbiome in periodontal disease. Despite a modest level of sequencing (~2 lanes Illumina 76 bp PE) and high human DNA contamination (up to ~90%) we were able to partially reconstruct several oral microbes and to preliminarily characterize some systems-level differences between the healthy and diseased oral microbiomes.

Accurate and fast estimation of taxonomic profiles from metagenomic shotgun sequences

Background

A major goal of metagenomics is to characterize the microbial composition of an environment. The most popular approach relies on 16S rRNA sequencing, however this approach can generate biased estimates due to differences in the copy number of the gene between even closely related organisms, and due to PCR artifacts. The taxonomic composition can also be determined from metagenomic shotgun sequencing data by matching individual reads against a database of reference sequences. One major limitation of prior computational methods used for this purpose is the use of a universal classification threshold for all genes at all taxonomic levels.

Results

We propose that better classification results can be obtained by tuning the taxonomic classifier to each matching length, reference gene, and taxonomic level. We present a novel taxonomic classifier MetaPhyler (http://metaphyler.cbcb.umd.edu), which uses phylogenetic marker genes as a taxonomic reference. Results on simulated datasets demonstrate that MetaPhyler outperforms other tools commonly used in this context (CARMA, Megan and PhymmBL). We also present interesting results by analyzing a real metagenomic dataset.

Conclusions

We have introduced a novel taxonomic classification method for analyzing the microbial diversity from whole-metagenome shotgun sequences. Compared with previous approaches, MetaPhyler is much more accurate in estimating the phylogenetic composition. In addition, we have shown that MetaPhyler can be used to guide the discovery of novel organisms from metagenomic samples.

Pituitary function impairment after moderate traumatic brain injury

To determine the prevalence of pituitary hormone deficiencies after moderate traumatic brain injury (TBI). We conducted a prospective cohort and included 75 patients with moderate TBI with GCS between 9 and 13 who referred to emergency department of Shariati Hospital, Tehran/Iran, during 2004-2007. Pituitary hormones were assessed 3 and 6 months after injury. In 3(rd) month post-injury, 39 cases had not any pituitary dysfunction; however, deficiencies in one, two and three of the pituitary hormones were found in 26, 8 and 2 patients, respectively. Twenty one patients showed a deficiency in one of the pituitary hormones and only one case with deficiency of two after 6 months. The most prevalent changes occur in IGF-1 and LH/FSH after moderate TBI. However, the whole deficiencies decrease over the time.

Effects of water deficit and spraying of dessicant on yield, yield components and water use efficiency of wheat genotypes

To evaluate yield, yield components and water use efficiency of bread wheat in water stress conditions and spraying of dessicant, a field experiment was carried out in 2006-2007 and 2007-2008. Main plots were assigned to two levels of water stress treatments; D1: optimum irrigation and D2: cessation of watering from anthesis to maturity stages. Sub plots were assigned to eight bread wheat genotypes; and assimilates limitations with two levels: P1: no source limitation and P2: inhibition of current photosynthesis were in sub-sub plots. Grain yield, biological yield, harvest index, the number of grains per spike, thousand grain weight and water use efficiency were significantly influenced by irrigation treatments and source limitation. Grain Yield (GY) significantly decreased by 35 and 68% under water deficiency and postanthesis photosynthetic inhibition, respectively; compared with control. Water use efficiency was higher for well-watered compared with postanthesis drought stress conditions. WUEgrain decrease due to water deficit was attributed to grain yield reduction. Under water stress, current photosynthetic inhibition reduced grain yield by 62%, but under well-watered condition; it significantly decreased grain yield by 71%, that indicate the source is limititing factor under different irrigation regimes. Considering that C-81-10, 9103 and 9116 genotypes showed the highest grain yield, potential for reserves and remobilizations of assimilates under different irrigation conditions; thus, these genotypes could be introduced as promising in breeding programs for arid and semi-arid regions.

Hospital management of abdominal trauma in Tehran, Iran: a review of 228 patients

OBJECTIVE

Today, trauma is a major public health problem in some countries. Abdominal trauma is the source of significant mortality and morbidity with both blunt and penetrating injuries. We performed an epidemiological study of abdominal trauma (AT) in Tehran, Iran. We used all our sources to describe the epidemiology and outcome of patients with AT.

METHODS

This study was done in Tehran. The study population included trauma patients admitted to the emergency department of six general hospitals in Tehran during one year. The data were collected through a questionnaire that was completed by a trained physician at the trauma center. The statistical analysis was performed using the SPSS software (version 11.5 for Windows). The statistical analysis was conducted using the chi-square and P < 0.05 was accepted as being statistically significant.

RESULTS

Two hundred and twenty-eight (2.8%) out of 8,000 patients were referred to the above mentioned centers with abdominal trauma. One hundred and twenty-five (54.9%) of the patients were in their 2nd and 3rd decades of life and 189 (83%) of our patients were male. Road traffic accidents (RTA) were the leading cause of AT with 119 (52.2%) patients. Spleen was the commonly injured organ with 51 cases. Following the analysis of injury severity, 159 (69.7%) patients had mild injuries (ISS < 16) and 69 (30.3%) patients had severe injuries (ISS equal to 16). The overall mortality rate was 46 (20.2%).

CONCLUSIONS

Blunt abdominal trauma is more common than penetrating abdominal trauma. Road traffic accidents and stab wound are the most common causes of blunt and penetrating trauma, respectively. Spleen is the most commonly injured organ in these patients. The mortality rate is higher in blunt trauma than penetrating one.

Prognostic factors in the persistence of posttraumatic epilepsy after penetrating head injuries sustained in war

Object

The goal of this paper was to investigate the long-term outcome and the possible prognostic factors that might have influenced the persistence of posttraumatic epilepsy after penetrating head injuries sustained during the Iraq–Iran war (1980–1988).

Methods

In this retrospective study, the authors evaluated 189 patients who sustained penetrating head injury and suffered posttraumatic epilepsy during the Iraq–Iran war (mean 18.6 ± 4.7 years after injury). The probabilities of persistent seizures (seizure occurrence in the past 2 years) in different periods after injury were estimated using the Kaplan-Meier method. The possible prognostic factors (patients and injury characteristics, clinical findings, and seizure characteristics) were studied using log-rank and Cox regression analysis.

Results

The probability of persistent seizures was 86.4% after 16 years and 74.7% after 21 years. In patients with < 3 pieces of shrapnel or no sphincter disturbances during seizure attacks, the probability of being seizure free after these 16 and 21 years was significantly higher.

Conclusions

Early seizures, prophylactic antiepileptics drugs, and surgical intervention did not significantly affect long-term outcome in regard to persistence of seizures.

The cerebral arterial circle (circulus arteriosus cerebri): an anatomical study in fetus and infant samples

BACKGROUND

Many studies have investigated the variations in the anatomy of each segment of the cerebral arterial circle while a few have addressed the variations of the cerebral arterial circle as a whole.

METHODS

Thirty brains of recently deceased Iranian infants and fetuses were dissected. The dissection process was filmed and digitized so as to be readily available for further studies. The variations of the circle as a whole and segmental variations were evaluated.

RESULTS

Variants with uni- and bilateral hypoplasia of posterior communicating arteries (PcoAs) were the most common in our study, similar to previous works. No aplasia of the precommunicating part of the anterior cerebral artery (A1), the precommunicating part of the posterior cerebral artery (P1) and anterior communicating artery was seen. Hypoplasia of the right and left PcoA was observed in 8 and 5 cases, respectively. Aplasia of the right PcoA was found in 16.6% and of the left PcoA in 3.3%.

CONCLUSION

In this study, we confirmed the previously described finding that the symmetrical, circular configuration of the circulus arteriosus cerebri is present in only about 42.1%. The main differences between the fetal and adult disposition are the diameter of the PcoA and the circular part of the posterior cerebral artery. According to previous studies, the fetal brain older than 4 months has anatomical characteristics very similar to the adult's circle; our finding was mostly similar to adult samples as most samples were from infants, not fetuses.

Are the distributions of variations of circle of Willis different in different populations? - Results of an anatomical study and review of literature

BACKGROUND

Previous studies have proposed correlation between variants of the cerebral arterial circle (also known as circle of Willis) and some cerebrovascular diseases. Differences in the incidence of these diseases in different populations have also been investigated. The study of variations in the anatomy of the cerebral arterial circle may partially explain differences in the incidence of some of the cerebrovascular diseases in different ethnic or racial groups. While many studies have investigated the variations in the anatomy of each segment of the cerebral arterial circle, few have addressed the variants of the cerebral arterial circle as a whole. Similarly, the frequency of occurrence of such variants in different ethnic or racial groups has not been compared.

METHODS

102 brains of recently deceased Iranian males were dissected, in order to observe variations in the anatomy of the cerebral arterial circle. The dissection process was recorded on film and digitized. One resized picture from each dissection, showing complete circle has been made available online. The variations of the circle as whole and segmental variations were compared with previous studies.

RESULTS

On the whole, the frequencies of the different variants of the entire cerebral arterial circle and segmental variations were comparable with previous studies.More specifically variants with uni- and bilateral hypoplasia of posterior communicating arteries were the most common in our study, similar to the previous works. No hypoplasia of the precommunicating part of the left anterior cerebral artery (A1), aplasia of A1 or the precommunicating part of the posterior cerebral artery (P1) was seen. In 3% both right and left posterior communcating arteries were absent.

CONCLUSION

The anatomical variations found in the cerebral arterial circle of the Iranian males in the current study were not significantly different to those of more diverse populations reported in the literature. While taking into account potential confounding factors, the authors conclude that based on available studies, there is no evidence suggesting that the distributions of the variations of cerebral arterial circle differ in different populations.

Childhood trauma fatality and resource allocation in injury control programs in a developing country

Background

Only a few studies have addressed the trimodal distribution of childhood trauma fatalities in lesser developed countries. We conducted this study to evaluate pre-hospital, Emergency Department (ED) and in-hospital distribution of childhood injury-related death for each mechanism of injury in Tehran, Iran. This information will be used for the efficient allocation of the limited injury control resources in the city.

Methods

We used Tehran's Legal Medicine Organization (LMO) database. This is the largest and the most complete database that receives information about trauma fatalities from more than 100 small and large hospitals in Tehran. We reviewed all the medical records and legal documents of the deceased registered in LMO from September 1999 to September 2000. Demographic and injury related characteristics of the children 15 years old or younger were extracted from the records.

Results

Ten percent of the 4,233 trauma deaths registered in LMO occurred among children 15 years old or younger. Motor vehicle crashes (MVCs) (50%), burns (18%), falls (6%) and poisonings (6%) were the most common mechanisms of unintentional fatal injuries. Prehospital, emergency department and hospital deaths comprised 42%, 20% and 37% of the trauma fatalities, respectively. While, more than 80% of fatal injuries due to poisoning and drowning occurred in prehospital setting, 92% of burn-related fatalities happened after hospital admission.

Conclusion

Injury prevention is the single most important solution for controlling trauma fatalities due to poisoning and drowning. Improvements in the quality of care in hospitals and intensive care units might substantially alleviate the magnitude of the problem due to burns. Improvements in prehospital and ED care might significantly decrease MVC and falls-related fatalities.

Prophylactic antibiotic for prevention of posttraumatic meningitis after traumatic pneumocephalus: design and rationale of a placebo-controlled randomized multicenter trial [ISRCTN71132784]

Background

The purpose of this study is to compare the efficacy of prophylactic antibiotic for prevention of meningitis in acute traumatic pneumocephalus patients.

Methods

In this prospective, randomized controlled clinical trial, 200 selected head injury patients with traumatic pneumocephalus are randomly assigned to receive intravenous antibiotics (2 grams Ceftriaxone twice a day), oral antibiotics (Azithromycin) or placebo for at least 7 days after trauma. The patients will be followed for one month posttrauma.

Conclusion

The authors hope that this study helps clarifying the effectiveness and indications of antibiotics in prevention of meningitis in traumatic pneumocephalus after head injury and in specific subgroup of these patients.

Comparing logistic models based on modified GCS motor component with other prognostic tools in prediction of mortality: results of study in 7226 trauma patients

A simple reproducible and sensitive prognostic trauma tool is still needed. In this article we have introduced modified GCS motor response (MGMR) and evaluated the performance of logistic models based on this variable. The records of 8452 trauma patients admitted to major hospitals of Tehran from 1999 to 2000 were analysed. 7226 records with known outcome were included in our study. Logistic models based on outcome (death versus survival) as a dependent variable and Injury Severity Score (ISS), Revised Trauma Score (RTS), Glasgow Coma Scale (GCS), GCS motor component (GMR) and MGMR (following command [=2], movement but not following [=1] command and without movement [=0]) were compared based on their accuracy and area under the Receiver Operating Characteristic (ROC) curve. The accuracy of the Trauma and Injury Severity Score (TRISS), RTS, GCS, GMR and MGMR models were almost the same. Considering both the area under the ROC curve and accuracy, the age included MGMR model was also comparable with other age included models (RTS+age, GCS+age, GMR+age). We concluded that although in some situations we need more sophisticated models, should our results be reproducible in other populations, MGMR (with or without age added) model may be of considerable practical value.

Play dough as an educational tool for visualization of complicated cerebral aneurysm anatomy

BACKGROUND

Imagination of the three-dimensional (3D) structure of cerebral vascular lesions using two-dimensional (2D) angiograms is one of the skills that neurosurgical residents should achieve during their training. Although ongoing progress in computer software and digital imaging systems has facilitated viewing and interpretation of cerebral angiograms enormously, these facilities are not always available.

METHODS

We have presented the use of play dough as an adjunct to the teaching armamentarium for training in visualization of cerebral aneurysms in some cases.

RESULTS

The advantages of play dough are low cost, availability and simplicity of use, being more efficient and realistic in training the less experienced resident in comparison with the simple drawings and even angiographic views from different angles without the need for computers and similar equipment. The disadvantages include the psychological resistance of residents to the use of something in surgical training that usually is considered to be a toy, and not being as clean as drawings or computerized images.

CONCLUSION

Although technology and computerized software using the patients' own imaging data seems likely to become more advanced in the future, use of play dough in some complicated cerebral aneurysm cases may be helpful in 3D reconstruction of the real situation.

Comparison of artificial neural network and logistic regression models for prediction of mortality in head trauma based on initial clinical data

Background

In recent years, outcome prediction models using artificial neural network and multivariable logistic regression analysis have been developed in many areas of health care research. Both these methods have advantages and disadvantages. In this study we have compared the performance of artificial neural network and multivariable logistic regression models, in prediction of outcomes in head trauma and studied the reproducibility of the findings.

Methods

1000 Logistic regression and ANN models based on initial clinical data related to the GCS, tracheal intubation status, age, systolic blood pressure, respiratory rate, pulse rate, injury severity score and the outcome of 1271 mainly head injured patients were compared in this study. For each of one thousand pairs of ANN and logistic models, the area under the receiver operating characteristic (ROC) curves, Hosmer-Lemeshow (HL) statistics and accuracy rate were calculated and compared using paired T-tests.

Results

ANN significantly outperformed logistic models in both fields of discrimination and calibration but under performed in accuracy. In 77.8% of cases the area under the ROC curves and in 56.4% of cases the HL statistics for the neural network model were superior to that for the logistic model. In 68% of cases the accuracy of the logistic model was superior to the neural network model.

Conclusions

ANN significantly outperformed the logistic models in both fields of discrimination and calibration but lagged behind in accuracy. This study clearly showed that any single comparison between these two models might not reliably represent the true end results. External validation of the designed models, using larger databases with different rates of outcomes is necessary to get an accurate measure of performance outside the development population.

Occupational injuries in Tehran

As the first step in evaluation of the magnitude of the occupational injuries (OIs) in our community, we focused on hospital records of more than 8400 hospitalized trauma patients in six large university hospitals during 13 months of data gathering process. Fourteen percent of 8426 trauma patients had OIs (1180 cases) and 95% of them were male. Adults 19-39 years comprised 63% of the patients. Eleven percent of the patients were 18 years old or younger. Construction workers (26%), simple workers (26%), and industrial workers (17%) comprised nearly 70% of the OIs. Falls (39%) and striking by blunt objects (29%) were the most common mechanisms of injury. More than 60% of the patients did not have any type of insurance. A younger patient has a higher the probability of being uninsured. Head (49%) wrist and hand (46%) and knee and leg (36%) injuries were the most common regions injured. Additional community-based studies are needed to determine the risk of OIs among different occupational categories, as well as to identify the most vulnerable groups.

Prophylactic administration of ceftriaxone for the prevention of meningitis after traumatic pneumocephalus: results of a clinical trial

OBJECT

The purpose of this study was to compare the efficacy of the prophylactic use of ceftriaxone for the prevention of meningitis in patients with acute traumatic pneumocephalus.

METHODS

In this prospective, single-institution, randomized clinical trial, 109 patients with mild head injury and traumatic pneumocephalus were randomly assigned to receive or not receive an antibiotic medication (ceftriaxone, 1 g given twice a day) until occurrence of meningitis or at least 5 days after trauma. The patients were followed up for 1 month posttrauma. The 109 patients were divided into two groups: 53 were assigned to the prophylactic antibiotics therapy group and 56 to the control group. The overall rate of meningitis was 20.1% and the rates of meningitis in the two groups were not significantly different. The results were the same when adjusted for the patient's Glasgow Coma Scale score, sex, and age, as well as for an intradural location of air, air volume, presence of cerebrospinal fluid (CSF) rhinorrhea or CSF otorrhea, radiological sign of a skull base fracture, or intracranial hemorrhage.

CONCLUSIONS

The results of this study do not substantiate the efficacy of ceftriaxone used in the prevention of meningitis in patients with traumatic pneumocephalus after mild head injury or in any specific subgroup of these patients. Cerebrospinal fluid rhinorrhea and intracranial hemorrhage may be considered primary risk factors for the development of meningitis in patients with posttraumatic pneumocephalus and, in the absence of these symptoms, intradural location of air and air volume greater than 10 ml may be considered secondary risk factors. Further studies in this area are warranted.

Bilateral asynchronous acute epidural hematoma : a case report

Background

Bilateral extradural hematomas have only rarely been reported in the literature. Even rarer are cases where the hematomas develop sequentially, one after removal of the other. Among 187 cases of operated epidural hematomas during past 4 years in our hospital, we found one case of sequentially developed bilateral epidural hematoma.

Case Presentation

An 18-year-old conscious male worker was admitted to our hospital after a fall. After deterioration of his consciousness, an emergency brain CT scan showed a right temporoparietal epidural hematoma. The hematoma was evacuated, but the patient did not improve afterwards. Another CT scan showed contralateral epidural hematoma and the patient was reoperated. Postoperatively, the patient recovered completely.

Conclusions

This case underlines the need for monitoring after an operation for an epidural hematoma and the need for repeat brain CT scans if the patient does not recover quickly after removal of the hematoma, especially if the first CT scan has been done less than 6 hours after the trauma. Intraoperative brain swelling can be considered as a clue for the development of contralateral hematoma.

Spinal subdural hematoma revealing hemophilia A in a child: A case report

BACKGROUND: Intraspinal bleeding especially in the form of subdural hematoma is rare in hemophiliacs. In the present case, we report a neglected hemophilic A child with such a problem and discuss its management options. CASE PRESENTATION: A 9-year old hemophilic A boy presented with quadriparesis, confusion and meningismus after a fall 4 days previously. There was no sign of direct trauma to his back. His CT Scan and MRI showed spinal extramedullary hematoma extended from C5 to L2. We corrected the factor VIII level, but two days later, the patient's lower limbs weakened to 1/5 proximally as well as distally. We performed a laminectomy from T11 to L2, according to the level of the maximal neurological deficit and recent deterioration course. The subdural hematoma was evacuated. The hematoma in other spinal levels was managed conservatively. In the week following the operation, the patient's neurological status approached normal. CONCLUSION: This case calls attention to the clinical manifestation, radiological features and management options of the rarely reported intraspinal hematoma in hemophilic children. Although this case has been managed operatively for its hematoma in the thoracolumbar region, at the same time it can be considered a successful case of conservative management of intraspinal hematoma in the cervicothoracic region. Both conservative and surgical management could be an option in managing these patients considering their neurological course.

Vestibular schwannoma with contralateral facial pain - case report

BACKGROUND

Vestibular schwannoma (acoustic neuroma) most commonly presents with ipsilateral disturbances of acoustic, vestibular, trigeminal and facial nerves. Presentation of vestibular schwannoma with contralateral facial pain is quite uncommon.

CASE PRESENTATION

Among 156 cases of operated vestibular schwannoma, we found one case with unusual presentation of contralateral hemifacial pain.

CONCLUSION

The presentation of contralateral facial pain in the vestibular schwannoma is rare. It seems that displacement and distortion of the brainstem and compression of the contralateral trigeminal nerve in Meckel's cave by the large mass lesion may lead to this atypical presentation. The best practice in these patients is removal of the tumour, although persistent contralateral pain after operation has been reported.

Surgical simulation software for insertion of pedicle screws

OBJECTIVE

As the first step toward finding noninvasive alternatives to the traditional methods of surgical training, we have developed a small, stand-alone computer program that simulates insertion of pedicle screws in different spinal vertebrae (T10-L5).

METHODS

We used Delphi 5.0 and DirectX 7.0 extension for Microsoft Windows. This is a stand-alone and portable program.

RESULTS

The program can run on most personal computers. It provides the trainee with visual feedback during practice of the technique. At present, it uses predefined three-dimensional images of the vertebrae, but we are attempting to adapt the program to three-dimensional objects based on real computed tomographic scans of the patients. The program can be downloaded at no cost from the web site: www.tums.ac.ir/downloads

CONCLUSION

As a preliminary work, it requires further development, particularly toward better visual, auditory, and even proprioceptive feedback and use of the individual patient's data.

Cervical epidural actinomycosis. Case report

Cervical actinomycosis causing spinal cord compression is a rare clinical entity. In a review of the literature, the authors found only 13 cases with actinomycosis-related spinal neurological deficit. The authors describe the case of a 26-year-old man who presented with neck pain and partial paresis of the upper limbs. Magnetic resonance imaging revealed a long cervical epidural enhancing lesion that extended from C-1 to T-2. The radiological findings resembled metastasis and other epidural infections. The patient was treated medically with penicillin and amoxicillin for 7 months and recovered neurologically. The authors conclude that although cervical epidural actinomycosis is a rare clinical entity resembling metastasis and other infections in this region, it should be considered so that this unique infection can be diagnosed in the least invasive fashion and, whenever possible, unnecessary surgery can be avoided.

Teeth in the cerebellopontine angle: an unusual dermoid tumour

An hour-glass-shaped multidensity lesion found by CT in a 6-year-old boy who had been admitted to the emergency department after a mild car accident. This lesion turned out to be a congenital dermoid tumour of the right cerebellopontine angle-tentorial notch region containing 12 mature teeth and 14 pseudocarilagenous structures. This is the first case of dermoid tumour containing so many teeth, reported in an asymptomatic person and located off the midline.