[Truncated abstract] Asthma affects millions of people worldwide and places a substantial burden on the healthcare system. Despite advances in our understanding of disease mechanisms and the role of respiratory viruses in asthma exacerbations, there is little known regarding the role of the epithelium in commonly observed structural changes in the airway wall. The epithelium of the airways provides an essential protective barrier between the environment and underlying structures and is responsible for the secretion of diverse compounds. Since it is likely that dysregulated epithelial characteristics and function in childhood asthma are critical determinants of disease progression in adults, it is pertinent to investigate the cellular mechanisms involved in paediatric asthma. However, full comprehension of paediatric respiratory diseases and the childhood antecedents of adult respiratory disease are currently hampered by the difficulty in obtaining relevant target organ tissue and most of the data to date have been generated from studies involving adults or commercially derived cell lines. This laboratory has successfully developed methodologies of obtaining and studying samples of paediatric primary airway epithelial cells (pAECs) and has identified significant biochemical and functional differences between healthy non-atopic (pAECHNA) and atopic asthmatic (pAECAA) airway cells, which have assisted in the identification of potential mechanisms responsible for abnormal epithelial function. Stevens 2009 ... Exposure of pAECs with RV resulted in elevated PAI-1 mRNA expression and reduced MMP-9 release in both pAECAA and pAECHNA samples. Collectively, the data presented indicate that RV exposure induces a pronounced antiproliferative and retardative repair effect in pAECAA and that the presence of virus may have a role in the PAI-1 and MMP expression witnessed in these cells. In conclusion, this investigation has further characterised the essential role the airway epithelium plays in childhood asthma by demonstrating for the first time that pAECs from asthmatic children lack the ability to successfully repair mechanically induced wounds. This investigation also showed that PAI-1 is elevated in pAECAA and has a functional role in the pAEC proliferative and regenerative processes. It was demonstrated that MMP-2 and MMP-9 activities and the MMP-9/TIMP-1 as well as MMP2/TIMP2 ratios were significantly reduced in pAECAA thereby providing additional evidence that there is a dysregulation in the mechanisms that monitor the turnover of the ECM in childhood asthma. Furthermore, this study has shown for the first time that pAECs from untreated mild atopic-asthmatic children are more sensitive to the pathogenic effects of RV than healthy control cells and that RV exposure delays cellular proliferation and repair. Ultimately, these findings support the hypothesis postulated and provide evidence that indeed the dysregulated epithelial functional characteristics seen in childhood mild asthma may be a critical determinant of disease progression in adults.

The objective of this thesis is to investigate the pathophysiology of the coronary slow phenomenon (CSFP). The experimental work of this thesis has taken a 'bedside to benchtop' approach with clinical observations made in the second chapter guiding the application of basic research techniques in subsequent chapters. Chapter 1 ; The CSFP is a disorder of the coronary microcirculation ; hence chapter 1 specifically reviews the current understanding of this vascular territory and concludes with a summary of the clinical disorders affecting it, concentrating on the CSFP. Chapter 2 ; investigated the angiographic response of the CSFP to a calcium channel blocking agent with antianginal efficacy in this disorder ( mibefradil ). Mibefradil administration was associated with an acute improvement of coronary flow indices which occurred despite background vasodilator therapy with conventional calcium channel antagonists. Chapter 3 ; investigated the in vitro response of human microvessels to mibefradil in comparison to conventional calcium channel blockers. Mibefradil was found to be a more potent agent both in terms of vasodilatation and the prevention of vasoconstriction. Both findings support the clinical observations and point to its selective action on the calcium T channel subtype as a potential mechanism. Chapter 4 ; examined the expression of T type calcium channels at the level of the microvasculature and compared T channel expression in CSFP patients and controls. T channels were found to be expressed at two or more orders of magnitude greater than the L channels. No difference in T channel expression between patients and controls was found. Chapter 5 ; examined the vasomotor reactivity of isolated subcutaneous arterial microvessels to various vasoactive substances between controls and CSFP patients. CSFP patients were found to have a selective hyper reactivity to endothelin. Chapter 6 ; examined plasma endothelin levels in CSFP patients and controls and the relationship between endothelin levels and angina frequency in the CSFP cohort. A small but statistically significant elevation of endothelin-1 was present in patients with the CSFP. A positive association between plasma endothelin fluctuation and angina frequency was also found in the CSFP cohort but not between absolute endothelin levels and angina symptoms. / Thesis (Ph.D.)-- The University of Adelaide, School of Medical Sciences, 2006.

Abdominal Aortic Aneurysms (AAA) are amongst the top ten most common cause of death in those over 55 years of age. The disease is usually asymptomatic, often being diagnosed incidentally. Once diagnosed, elective repair of an AAA results in excellent long-term survival with a 3-5% operative mortality. However, up to one half of patients present with ruptured aneurysms, a complication that carries an 80% mortality in the community, and of those reaching hospital, a 50% mortality. Clearly early diagnosis and treatment results in improved survival. Screening for AAA, with ultrasound, would detect aneurysms early, prior to rupture. However, debate continues over the cost effectiveness of population based screening programmes. The identification of a sub-population at a higher risk of developing AAA would increase the yield of a screening prograrmne. A number of populations have been examined, none of which have received international acceptance. About 20% of patients with an AAA have a family history of an aneurysm. The disease is also considered to be a disease of Caucasians, both facts suggesting a strong genetic component to the disease. Perhaps a genetically identified sub-population at a high risk of developing an AAA would prove to be an ideal population for screening. This thesis examines the incidence of aneurysms and the family histories of patients with AAA in the Otago region of New Zealand. Almost twenty percent of the population has a family history of AAA. DNA was collected from each of these patients for genetic analysis. The population was divided into familial AAA and non-familial AAA for the purpose of genetic analysis and compared to a control population. AAA is believed to be a disease of Caucasians; a non-Caucasian population with a low incidence of AAA may prove to be a good control population for genetic studies. A literature review demonstrated a higher incidence of AAA in Caucasians than other ethnic groups and within Caucasians a higher incidence in patients of Northern European origin. The incidence was low in Asian communities, even in studies involving of migrant Asian populations. The New Zealand Maori are believed to have originated from South East Asia, therefore could be expected to have a low incidence of AAA and would make an ideal control population for genetic studies. A pilot study was undertaken to examine the incidence of AAA in the New Zealand Maori. The age standardised incidence of AAA proved to be at least equal in Maori to non-Maori, with a more aggressive form of the disease in Maori, manifesting with a younger age at presentation and a higher incidence of ruptured aneurysms at diagnosis. It is well known that at the time of surgery, an AAA

Orientador: Celio Raimundo Machado / Banca: Urara Kawazoe / Banca: Carlos Wilson Gomes Lopes / Banca: Luis Francisco Prata / Banca: Antonio Carlos Paulillo / Resumo: A infecção experimental por Eimeria stiedae em coelhos foi realizada com o objetivo de avaliar os sinais clínicos, alterações hematológicas, metabólicas e anatomopatológicas. Foram utilizados 50 coelhos, raça Nova Zelândia, brancos, com idade entre 40 - 60 dias e de pesos semelhantes. Os animais foram randomizados com relação ao peso e distribuídos em 2 grupos experimentais: grupo infectado, inoculado com 1ml de solução contendo 1x104 oocistos esporulados de E. stiedae; grupo controle, inoculado 1 ml de água destilada. Os animais foram avaliados semanalmente, durante 28 dias, a partir da data de inoculação. Os dados foram avaliados utilizando-se método estatístico não paramétrico pelo teste de Wilcoxon ao nível de 5% de significância. Coelhos infectados com oocistos esporulados de Eimeria stiedae tiveram cirrose hepática que afetou o funcionamento normal do referido órgão repercutindo em produção de proteínas de fase aguda e ocasionando consideráveis alterações metabólicas. / Abstract: The experimental infection by Eimeria stiedae in rabbits was performed to evaluate the clinical signs, hematological, metabolic and pathological changes. Fifty rabbits were used, New Zealand race, white, aged 40 to 60 days and of similar weight. The animals were randomized to the weight and distributed into 2 experimental groups: infected group, inoculated with 1 ml of solution containing 1x104 sporulated oocysts of Eimeria stiedae; control group, inoculated 1 ml of distilled water. The animals were evaluated weekly, for 28 days from the date of inoculation. A statistical was used non-parametric Wilcoxon test method at 5% level of significance. Rabbits infected with sporulated oocysts of Eimeria stiedae had liver cirrhosis that affected the normal functioning of the body resulting in production of acute phase proteins and cause considerable metabolic changes. / Doutor

Made available in DSpace on 2014-06-11T19:33:26Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-02-02Bitstream added on 2014-06-13T21:06:05Z : No. of bitstreams: 1 freitas_flc_dr_jabo.pdf: 1139081 bytes, checksum: 856bf3c96a6f7eed40da1a35b470f7ae (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A infecção experimental por Eimeria stiedae em coelhos foi realizada com o objetivo de avaliar os sinais clínicos, alterações hematológicas, metabólicas e anatomopatológicas. Foram utilizados 50 coelhos, raça Nova Zelândia, brancos, com idade entre 40 - 60 dias e de pesos semelhantes. Os animais foram randomizados com relação ao peso e distribuídos em 2 grupos experimentais: grupo infectado, inoculado com 1ml de solução contendo 1x104 oocistos esporulados de E. stiedae; grupo controle, inoculado 1 ml de água destilada. Os animais foram avaliados semanalmente, durante 28 dias, a partir da data de inoculação. Os dados foram avaliados utilizando-se método estatístico não paramétrico pelo teste de Wilcoxon ao nível de 5% de significância. Coelhos infectados com oocistos esporulados de Eimeria stiedae tiveram cirrose hepática que afetou o funcionamento normal do referido órgão repercutindo em produção de proteínas de fase aguda e ocasionando consideráveis alterações metabólicas. / The experimental infection by Eimeria stiedae in rabbits was performed to evaluate the clinical signs, hematological, metabolic and pathological changes. Fifty rabbits were used, New Zealand race, white, aged 40 to 60 days and of similar weight. The animals were randomized to the weight and distributed into 2 experimental groups: infected group, inoculated with 1 ml of solution containing 1x104 sporulated oocysts of Eimeria stiedae; control group, inoculated 1 ml of distilled water. The animals were evaluated weekly, for 28 days from the date of inoculation. A statistical was used non-parametric Wilcoxon test method at 5% level of significance. Rabbits infected with sporulated oocysts of Eimeria stiedae had liver cirrhosis that affected the normal functioning of the body resulting in production of acute phase proteins and cause considerable metabolic changes.

Abstract This study describes clinical and biochemical consequences of the 3243A→G mutation in the tRNALeu(UUR) gene of the mitochondrial DNA. Mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes (MELAS syndrome) is usually caused by this mutation. Demyelinating polyneuropathy was observed as a novel feature in a patient with the mutation. Based on electrodiagnostic examination the polyneuropathy was defined as being of the demyelinating, mixed (motor more than sensory) type. In a 1 year follow-up an approximately 7% reduction in both the motor and sensory nerve conduction velocities were observed. The effect and mechanism of action of nicotinamide treatment in a MELAS patient with the 3243A→G was studied. The blood NAD concentration increased linearly, being 24-fold elevated at 6 weeks of treatment. Blood lactate and pyruvate concentration decreased by 50% within three days and 24 h urine lactate content within 2 weeks. A clinical improvement together with a decrease in the lesion volume in magnetic resonance imaging within the first month were observed. Alleviation of the lactate accumulation during the nicotinamide treatment suggested that an increase in the cellular NAD+NADH concentration led to enhancement of the oxidation of reducing equivalents, suggesting that complex I of respiratory chain operates at non-saturating substrate concentration. Myoblasts cultured from patients carrying the 3243A→G mutation and from controls were used to measure ATP, ADP, catalase and superoxide dismutase activity, population growth, apoptotic cell death and the morphology of cytoskeletal components. ATP and ADP concentrations were decreased, suggesting a decrease in the adenylate pool. The superoxide dismutase and catalase activities were higher than in control cells, suggesting an increased production of reactive oxygen species due to respiratory chain dysfunction. No increase in apoptotic cell death was observed in proliferating myoblasts, but randomization of vimentin filament direction and length was observed and decreased population growth was associated with the mutation. The results show that the 3243A→G mutation leads to numerous secondary pathophysiological events. Based on the literature and the results of this study, similarities were found between the pathophysiology of 3243A→G mutation and other neurodegenerative diseases and aging.

This thesis project will investigate the effects of fasting on the serum levels of two key regulatory hormones, insulin and thyroid hormone (T3) and the effects of these hormones on the trafficking of Glut4 on soleus muscle.

No description available.

A thesis submitted to the Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the Degree of Doctor of Philosophy in Medicine. October 2017. / Background: Population-based knowledge of human biological growth and development processes is fundamental for assessing the health status of a community. This requires an understanding of the growth pattern for the children as well as the environmental stresses that disrupt or impede their growth. These stresses are usually easy to identify, but data on normal development and growth variation in most populations is surprisingly lacking. Instead, researchers typically compare growth in the population of interest to references formulated for European or US children. The problems associated with using non-population specific references are complex, and their application can lead to misrepresentations of the health status. In addition, the influence of environmental factors on dental development is still debated and the relationship of dental development with life history events, such as sexual maturity, is unclear. Aim: The aim of this study is to develop population-specific reference for permanent tooth formation and emergence among Black Southern Africans, to compare this reference with other population references, and to investigate the influence of sex and nutritional status on dental development. Method: Study design and population This is a cross sectional study. A total of 642 children comprising of 270 males and 372 females from primary and secondary schools were recruited over one and half years. Only participants whose parents and grandparents are indigenous Southern Africans were included. Participants were screened in a mobile dental truck fitted with digital panoramic x ray. Systematic Review A literature search of PubMed, Scopus, Ovid, Database of Open Access Journals and Google Scholar was undertaken. All eligible studies published before December 28, 2016 were reviewed and analyzed. Meta-analysis was performed on 28 published articles using the Demirjian and/or Willems methods to estimate chronological age. The weighted mean difference at 95% confidence interval was used to assess accuracies of the two methods in predicting the chronological age of children. Tooth formation in Southern Africa To investigate tooth formation, all the 642 Black Southern African children comprising of 270 males and 372 females were recruited. The panoramic radiograph of each child was analysed and the dental maturity score of the left mandibular permanent teeth was obtained according to the Demirjian et al. (1973) method. The dental maturity score of each child was converted to dental age using standard tables and percentiles curves for both sexes by Demirjian et al. (1973). The ages of attainment of specific maturity stages were calculated with pr obit analysis and compared by sex and population. Comparisons of age estimation methods For comparison of the common methods used in estimation of age, 540 children (233 males and 307 females out of the 642 children were recruited. This is because all the children aged 16 years and above have reached 100% maturity and hence excluded from the study. Panoramic radiographs of the children were analyzed and the dental maturity scores of the left mandibular permanent teeth were calculated according to the Demirjian et al. (1973), Demirjian and Goldstein (1976) and Willems et al (2001) methods. The dental maturity scores were converted to dental ages using standard tables and percentiles curves for males and females (Demirjian et al. 1973; Demirjian and Goldstein 1976; Willems et al. 2001). The dental ages obtained were compared to the chronological ages of the children and the mean differences obtained by the three methods compared. Nutrition and tooth formation Effect of nutrition on tooth formation was investigated on all the 642 Black Southern African children comprising of 270 males and 372 females were recruited. The Panoramic radiograph of each child was analysed using the Demirjian et al. (1973) method. The dental maturity score of each child was converted to dental age using standard tables and percentiles curves for both males and females by Demirjian et al. (1973). In addition, measures of nutritional status such as, height, weight, mid upper arm circumference and head circumference were obtained from the children. The timing, sequence of emergence and the effect of nutrition on tooth emergence To investigate tooth emergence and the influence of nutritional status on emergence, information on type of teeth and number of teeth emerged were collected from 639 (266 males and 373 females) Black Southern African children aged 5-20 years out of the total 642 children because the emergence data for 3 children were found to be incomplete. An emerged tooth was defined as a tooth with any part of its crown penetrating the gingiva and visible in the oral cavity. Height, weight, mid upper arm circumference and head circumference of the participants were measured. Children with any form of tooth impaction and agenesis were excluded from the study. Life history events and dental development To determine the association between tooth development and life history variables, mean ages of attainment of sexual maturity stages were adapted from Lundeen et al. (2015) and Norris and Richter (2005) to identify if any stage of dental development co-occured with life history events. Southern Africa specific reference values The WITS Atlas was developed using the tooth formation stage with the highest frequency for each tooth. This stage was considered the developmental reference for an age cohort. Southern African tables of conversion of maturity scores were generated separately for males and females using polynomial regression functions (3rd degree). Maturity curves were plotted to determine the dental maturity curves for each sex. The Southern African specific tables of conversion of maturity score were tested on 540 participants aged 5 to 15.99 years and the results compared to the Willems and Demirjian methods of age estimation. Data were analysed with Stata 12 for Windows. The analysis included frequencies and cross-tabulations. Associations between categorical variables were tested with chi square while those between continuous variables were tested with Student’s t-tests. The mean ages of emergence and standard deviation were computed using probit analysis. Sex and population comparisons were done using Student’s t-tests. The height and BMI were converted to z-scores using WHO z-scores for age tables (WHO 1995). A cut-off z-score of ≤−2 for BMI/height was used to place children into underweight/short for age, ≥-2 to 2.0 for normal, and ≥2 for overweight/obese/tall for age categories. Mean age of emergence and mean age of attainment of maturity stages were calculated for each tooth using these BMI subdivisions. Analysis of variance (ANOVA) and Games-Howell were used to determine the differences between the BMI/height subdivisions. A Student’s t-test was used to compare any two means whenever one of the three subdivisions of BMI did not yield a mean age of emergence. Spearman’s rho correlations between total number of teeth, dental maturity scores and anthropometric variables were done. A Shapiro-Wilk W test showed that the dependent variables (total number of teeth emerged and dental maturity) and the predictor variables were not normally distributed. Therefore, a generalized linear model (negative binomial) was used with the number of emerged teeth/dental maturity modelled as the dependent variable and anthropometric variables and age as predictors. Adequacy of fit was checked using the deviance residuals as recommended by McCullagh and Nelder (1989). The deviance residuals showed that it was normally distributed and the plot of the residuals against each of the covariates also showed model fit. As expected, the collinearity test showed that BMI, height and weight were significantly collinear. When these variables were excluded from the model, there was no difference in the values of the output. Hence, the variables were included in the final model for generalized linear regression analysis. The model was built using forward selection. Statistical significance was inferred at p<0.05. Results: Systematic review Meta-analysis revealed that the Willems method has better accuracy globally compared with the Demirjian method. Dental maturity in Black Southern Africans The females show advanced dental maturity and dental ages compared to males (p<0.05). Cross-population comparison shows the Southern African females are advanced in dental maturity compared to European and Asian children. Comparison of methods for estimating dental age The Original Demirjian method significantly overestimated the age of the males by 0.85 years and the females by 1.0 years (p<0.05) with the same mean absolute error of 1.1 years for both sexes. Similarly, the Modified Demirjian method significantly overestimated chronological ages of males (0.90 years) and females (1.21 years) with the highest mean absolute error of 1.1 years and 1.4 years for males and females respectively. The Willems method had the lowest, but still significant mean differences (0.2 years for males and 0.3 years for females) between the dental age and chronological age. It also demonstrated the least mean absolute errors for males (0.70 years) and females (0.68 years). Nutrition and tooth formation Significant advancements were found in the age of attainment of H stage for all the permanent teeth in the overweight group compared to the underweight group (p<0.05). Negative binomial regression analysis indicates that age, height, and BMI are significant predictors of the dental maturity score for males (p<0.05), while age, height, weight, BMI and head circumference are significant predictors of the dental maturity score for females. Tooth emergence Females have all the permanent teeth emerged earlier than males except for the third molars (p<0.05). Generally, Black Southern African children have similar ages and sequence of emergence as children from other sub-Saharan Africa countries. Black Southern African children have earlier mean ages of emergence of permanent teeth compared to children from the USA, Europe, Australia and Asia. Sexual dimorphism was noted in the sequence of emergence of I1/M1 in the mandible with the females having the M1I1 sequence as opposed to I1MI in males. The sequence of emergence of Southern African males is similar in both jaws to males from the USA and Europe but differs from Iranians and Pakistanis. Females show similar patterns of sequence with sub-Saharan African, Australian and US females in the maxilla. They display MI/I1 variation in the mandible. Nutrition and tooth emergence Overweight/obese children generally show significantly earlier emergence times compared to normal weight/severely underweight children (p<0.05). Females and tall children have more emerged teeth than shorter children when corrected for age and sex (p<0.05). The generalized linear regression model (negative binomial) shows that height, weight and BMI have significant associations with the number of emerged teeth (p<0.05). Dental development and life history variables The number of teeth emerged in males correlate strongly with chronological age (r=0.91, p=0.00) and height (r=0.89, p=0.00), moderately with mid-upper arm circumference (r=0.61, p=0.00) and weakly with head circumference (r=0.16, p=0.00). In females, the number of teeth emerged correlates strongly with chronological age (r=0.88, p=0.00) and height (r=0.83, p=0.00), moderately with mid-upper arm circumference (r=0.59, p=0.00), and weakly with head circumference (r=0.38, p=0.00). Similar patterns of correlation are found for dental maturity. The emergence of the maxillary and mandibular M2s co-occurs with the G2 stage of gonad development and the PH2 stage of pubic hair development in males. The M2s emerge coincident with the attainment of Tanner’s B2 breast stage and the PH2 pubic hair stage in females. The age of menarche does not coincide with any of the determined ages for emergence of teeth. Attainment of the H stage of development in the C1 co-occurs with the G2 stage of gonad development and shortly after the pubic hair stage PH2 in the males. In females, the attainment of the H stage of C1 formation occurs shortly before the attainment of the B2 stage of breast development. Furthermore, the H stage of P1 formation coincides with the PH2 stage of pubic hair development, shortly after the attainment of the stage B2 of breast development. The attainment of the H stage in P2 formation coincides with the age of menarche at approximately 13 years. Southern African specific reference A new dental atlas (WITS Atlas) was developed due to the significantly earlier ages of emergence and formation among Black Southern Africans. When compared to the London atlas, the canines, premolars and second molars are at least a year ahead in the WITS Atlas. Third molar formation and emergence occurs three years earlier in the WITS Atlas. Polynomial regression formulae were generated and Southern African specific conversion tables were generated for the males and females. The new tables of maturity scores show no overestimation of the chronological ages of males (0.045, p>0.05) and females (0.08, p>0.05). Compared to the Willems and Demirjian methods, the Southern African specific maturity tables showed the least mean absolute error for both sexes. Conclusion: There is sexual dimorphism in the timing of tooth emergence with females having earlier emergence times. Black Southern Africans show similarities in the ages and sequence of emergence of the permanent teeth with children from other sub-Saharan African countries but, they are advanced relative to children from the USA, Europe, Australia and Asia. Similarly, the Black Southern African children show advanced tooth formation compared to children from Europe, Asia and Australia. The Willems method is more accurate at estimating chronological age for forensic and anthropological purposes compared to the Demirjian methods that significantly overestimate the chronological age of children. Of the three methods tested on Black Southern African children, the Willems method is the most accurate in estimating chronological age. However; it significantly overestimated the chronological age of Black Southern African children. Hence, there is a need for population-specific reference values for use in the age estimation of Black Southern African children The WITS Atlas and new population-specific maturity tables for Black Southern African males and females were developed. The WITS Atlas differs significantly from the London atlas with earlier ages of tooth formation and emergence. The Southern African specific age estimation method shows good accuracy in the estimation of dental ages. By inference, this method could be used in other sub-Saharan African countries because of similarities in tooth formation and emergence times. Contrary to some studies, nutrition was found to have a significant influence on the number of teeth emerged and the timing of emergence. Obese/overweight/tall children tend to have earlier timing of emergence and more emerged teeth compared to their underweight peers. Similarly, obese/overweight/tall individuals attained the H stage of tooth formation of most teeth earlier than their underweight and normal weight age-mates. Emergence of second molars and the H stage of canine and first premolar formation co-occur with the onset of puberty in males and females. Menarche appears to coincide with the attainment of H stage of the mandibular second premolar. / LG2018

During a concussion, mechanical forces cause neuron cell strain that initiates dysfunction through the indiscriminate movement of ions through protein channels. Extracellular glutamate binds with cell membrane proteins (e.g. NR2A), which exacerbates the Ca2+ ion influx and prolongs neuron dysfunction. Genetic variation may be a factor in regulating glutamate binding and therefore cell recovery time. The NR2A subunit of NMDA contains a variable (GT)n nucleotide tandem repeat (VNTR) within GRIN2A promoter region. This VNTR has been shown to regulate transcription levels in a length dependent manner, where longer repeat decreases transcription of the NR2A subunit. The purpose of this study was to determine the association of the GRIN2A VNTR and recovery (days) as well as concussion severity scores within concussed athletes. The independent variable was VNTR (long allele vs. short allele). The primary dependent variable, recovery time, was defined as injury date to return to play (RTP) clearance date as determined by the physician. Participant RTP time was categorized as normal ( 20 days). Secondary dependent variables were assessed at the initial evaluation and included vestibular ocular score, Balance Error Scoring System (BESS) score, and Immediate Post Concussion and Cognitive Testing (ImPACT) module scores. All 51 participants were athletes, comprised of 38 males and 13 females with a mean age of 18.69 &#61617; 6.65. Participants were evaluated at a university concussion center. The standardized concussion evaluation consisted of cranial nerve, vestibular ocular tests, balance (Balance Error Scoring System), signs and symptoms (s/s), and neurocognitive (ImPACT) testing. Each participant was genotyped via saliva sample for the GRIN2A (GT)n repeat polymorphism (rs3219790). Data analysis consisted of descriptive and inferential statistics. Chi-squares were used to assess the association between VNTR (long allele versus short allele) and concussion recovery (prolonged versus normal). Regression analyses were used to estimate extent to which non-genetic factors and genotype contributed to concussion recovery group assignment. One-way ANOVAs were used to identify any significant differences in vestibular ocular, BESS, and ImPACT module scores between long and short alleles. Primary potential non-genetic contributing factors were age, race, sex, concussion history, dizziness at time of injury, history of migraines, and history of ADHD. The alpha level was set at p &#8804; .05. There were no differences between demographic or health history within the VNTR or recovery groups. There was a significant association (x2 = 4.01, p = 0.045) between the VNTR group (dominant model: LL versus SS + LS) and recovery, where the chance of prolonged recovery was 4.3 times greater for carriers of the homozygous long allele. There were no differences in concussion severity scores between VNTR group and concussion severity scores. This was the first study to investigate the association of the (GT)n VNTR within GRIN2A. We established a DNA collection, estimation, and genotyping protocol of the (GT)n VNTR for 96 samples and demonstrated accuracy of this genotyping method. Clinically, athletes carrying the long allele genotype may be predisposed to prolonged recovery following a concussive injury. / Kinesiology