The photopic negative response of the Light-adapted 3.0 ERG in clinical settings.

PURPOSE: To analyze the effects of different methods of measurement on the photopic negative response (PhNR), recorded as part of a standard ISCEV Photopic 3.0 ERG responses from patients with a variety of clinical diagnoses. METHODS: ERGs were recorded from both eyes of 97 patients (187 eyes) as part of a standard clinical assessment. The average age was 56.4 ± 15.7 years, the gender balance was 35 M, 62F, and only recordable responses of acceptable quality were included. PhNR was measured at an identifiable trough before (PhNR1) and after the i-wave (PhNR2), and the amplitudes and peak times were compared with a-, b- and i-wave corresponding parameters. PhNR components were measured: from baseline and from b-wave peak. Correlation between PhNR troughs and with ERG parameters were tested for right eyes. The possibility to predict and substitute PhNR2 amplitude from PhNR1 amplitude was also tested. RESULTS: PhNR1 was recordable in 97.3% of eyes and PhNR2 in 85.6%. An identifiable PhNR2 peak was found to occur before 65 ms at ~ 50% of the records, while in ~ 38% of the cases was within 65-75 ms in ~ 12%-after 75 ms. The correlation between the PhNR1 and PhNR2 peaks was quite strong (with coefficients 0.81-0.98, depending on method of measurement, and slopes close to 1). The average difference between predicted and measured PhNR2 was reasonably small in absolute (< 2 µV) and relative (< 2%) terms. The correlations between PhNR amplitudes and other ERG component amplitudes showed different ranges of correlation coefficients depending on the method of measurement: for the a-wave amplitudes the range of coefficients was 0.48-0.73, while for the b-wave amplitudes it was 0.30-0.95 and 0.39-0.65 for i-wave. CONCLUSION: The strong correlation between the two PhNR troughs could allow using PhNR1 when PhNR2 is poorly defined due to artifacts. Different methods of PhNR measurement lead to different correlations with other ERG parameters, and this needs to be considered when analyzing and comparing PhNR data between studies.

Traumatic Frontal Epidural Hematoma Caused by Multiple Arterial Injuries in the Anterior Fossa.

BACKGROUND: This case report illustrates the need to evaluate the possibility of multiple arterial sources when presented with a frontal epidural hematoma associated with facial trauma. CASE DESCRIPTION: The patient presented after being struck in the face by a baseball. Computed tomography of the brain revealed a large frontal epidural hematoma. Intraoperatively, bleeding from a frontal branch of the middle meningeal artery was encountered and cauterized, and the hematoma was removed. Routine follow-up imaging performed the next day showed a residual frontal hematoma; however, the epidural hematoma was in a more medial location than the initial hematoma. The patient was taken back to the operating room; after frontal lobe retraction and extensive exploration, a different source of bleeding from posterior ethmoidal artery feeders was encountered. After the second operation, the patient's hematoma did not recur, and he was discharged home with no neurologic deficits 3 days later. CONCLUSIONS: We report a case of an epidural hematoma caused by 2 distinct arterial feeders. We discuss radiologic review and operative management of anterior fossa epidural hematomas and stress the importance of considering arterial bleeding from sources other than the middle meningeal artery in anterior fossa epidural hematomas. We discuss the utility of preoperative angiography for these patients and reinforce the need for acute postoperative imaging to ensure successful operative and patient outcomes.

Association of sudden infant death syndrome with VEGF and IL-6 gene polymorphisms.

In the UK, Sudden Infant Death Syndrome (SIDS) is a major cause of postperinatal mortality up to the end of the first year of life. Several studies have found an association between cytokine IL-10 genotypes and SIDS. The aim of the present work was to test the hypothesis that SIDS is associated with high producer gene polymorphisms for certain proinflammatory cytokines and with low producer gene polymorphisms of certain antiinflammatory cytokines. DNA polymorphisms were investigated using sequence-specific primer (SSP)-polymerase chain reaction (PCR). Results demonstrated that SIDS and controls did not differ significantly with respect to genotype distributions for IL-4 -590 (chi(2) test, p = 0.164), IFN- gamma +874 (p = 0.050), or TGF-beta1 +869 (p = 0.322). However, significant associations with SIDS were seen for genotypes of VEGF -1154 (p = 0.005) and IL-6 -174 (p = 0.018). Comparison of allele frequencies for these cytokine genes between SIDS and control groups reflected the genotype data. Allele frequencies that did not demonstrate significant differences between test groups were IL-4 -590*T (chi2, p = 0.104), IFN- gamma +874*A (p = 0.052), and TGF-beta1 +869*C (p = 0.468). Those demonstrating significant differences between SIDS and control groups were VEGF -1154*A (p= 0.002, OR = 2.94, CI 1.46-6.02) and IL-6 -174*G (p= 0.034, OR = 2.18 CI 1.05-4.56). Thus, there are associations between SIDS and particular polymorphisms of VEGF and IL-6 cytokine genes in addition to those previously found in Manchester with another cohort of samples for the antiinflammatory cytokine IL-10. Moreover, these gene polymorphism associations suggest that the causation of SIDS is related to both fetal lung development and a child's innate ability to mount an inflammatory response to infection.

Interleukin-10 haplotype frequencies in children with gingivitis.

BACKGROUND: Polymorphisms in the promoter region of the interleukin (IL)-10 gene have been identified at positions -1082 (G-->A), -819 (C-->T), and -592 (C-->A). Linkage disequilibrium between alleles -819*C, and -592*C was observed. A previous study addressed the association between the -1082*A allele and gingivitis in white Caucasian children. The aim of this case-control study was to test whether differences could exist between children with and without gingivitis in the distribution of IL-10 alleles and haplotypes at positions -1082, -819, and -592. METHODS: A total of 248 subjects aged 8 to 12 years from the University Dental Hospital of Manchester were enrolled in this study. According to gingival and bleeding on probing indices, 84 children were classified as controls and 164 as children with gingivitis. Amplification refractory mutation system-polymerase chain reaction (ARMS-PCR) was used for genotyping IL-10 polymorphisms. Allele and haplotype frequencies were calculated by direct counting and by a haplotype frequency estimation (EH) program. Differences between subjects with gingivitis and controls in the frequency of haplotypes were determined by a chi2 test of homogeneity. RESULTS: The GCC/GCC genotype, which has been associated with increased production of IL-10, was significantly more frequent in controls than in children with gingivitis (36% versus 23%) (P=0.036). In addition, there was a marginally significant difference between controls and cases in the frequency of haplotypes (P=0.06). The GCC haplotype was more frequent in controls than in children with gingivitis (60% versus 50%). In contrast, the ACC and ATA haplotypes were more frequent in children with gingivitis (27% and 23% versus 19% and 21% in controls). CONCLUSION: These findings suggest that IL-10 gene promoter polymorphisms could have an active role in the pathogenesis of gingivitis in Caucasian children.

Role of posterior elements in the disc bulging of a degenerated cervical spine.

BACKGROUND: Many studies have been developed to characterize the mechanical behavior of the intervertebral disc specifically for the lumbar spine and there have been limited studies done on the cervical spine with the goal to evaluate the strength of the cervical spine under compression without any information on the bulging of the intervertebral discs. The goal of the current study is to examine the deformation response of the cervical intervertebral disc classified with grade III or greater degeneration and analyze the relationship between axial deformation and anterior and posterior bulge under compression up to 550 N. METHODS: Each specimen was compressed for 3 cycles to a maximum load of 550N in steps of 50 N. The bulge was measured using Linear Variable Differential Transformers (LVDTs on an intact spinal segment, spinal segment with post laminectomy, and spinal segment post facetectomy. RESULTS: The anterior budge for an intact spinal segment shows a change of slope at loads of 262N±66N. For a physiological load of 250N the vertical displacement or spine segment height was reduced by 10.1% for an intact segment and 8.78% for the laminectomy and facetectomy configurations with F = 0.159 (Fcrit = 3.89) with no statistical difference observed. For the post laminectomy there was a decrease of 35% in anterior bulge compared to the intact specimen. CONCLUSIONS: Our results show that for grade III disc degeneration the cervical segments bulging for both the laminectomy and facetectomy procedures are not significantly different. In post laminectomy the average anterior and posterior bulges are similar to the average anterior and posterior bulge post facetectomy.

Interleukin 10 genotype as a risk factor for sudden infant death syndrome: determination of IL-10 genotype from wax-embedded postmortem samples.

In a previous study an association was shown between SIDS and an interleukin-10 (IL-10) genotype. That study was carried out on frozen, unfixed tissue samples, but these are difficult to obtain. Fixed samples used for pathological examination are available. The purpose of this study was to extend the previous work by establishing methods to extract and genotype DNA from fixed, wax-embedded tissues specimens and to use the results to seek confirmation of the association between IL-10 genotype and SIDS in a larger collection of SIDS babies. Using an amplification refractory mutation system-polymerase chain reaction method, a total of 38 infants were genotyped for IL-10 alleles and compared with controls. There was a significant association between the IL-10 -592*A allele and SIDS, consistent with the earlier findings. This study lends support to the hypothesis that IL-10 genotype is related to the susceptibility of babies to SIDS.

Effects of nitrite and nitrate on the growth and acidogenicity of Streptococcus mutans.

UNLABELLED: It is hypothesised that exogenous nitrite acidified by metabolic products of acidogenic bacteria in the mouth will be converted to products which inhibit growth of the bacteria in question which contribute to dental caries. OBJECTIVES: The aims of this study were (1) to test the activity of both sodium nitrate and sodium nitrite at differing concentrations on the ability of Streptococcus mutans to lower the pH of its surroundings and hence (2) to determine whether either nitrate or nitrite might be bactericidal or bacteriostatic against S. mutans. METHODS: S. mutans NCTC 10449(T) was cultured in a liquid medium to which either sodium nitrate or sodium nitrite was added to a final concentration of 0.0, 0.2, 2.0, 20 or 200 mM, of which the first acted as a test substance negative control. After 24 h, the cultures were streaked onto agar to test for growth and the remaining culture used for pH measurement. The Mann-Whitney U-Test was used for statistical comparison of pH values. RESULTS: Nitrite at concentrations of 20 and 200 mM had a highly significant inhibitory effect (p < 0.001) on the ability of S. mutans NCTC 10449(T) to lower pH. Moreover, bacteria that had been subjected to these levels of nitrite were unable to recover on solid medium. Nitrate had no such effect on either the growth of the bacteria or on their ability to lower pH. CONCLUSIONS: It is concluded that nitrite, at final concentrations of either 20 or 200 mM, is both bactericidal and anti-acidogenic with respect to S. mutans, while lower concentrations of nitrite and all concentrations of nitrate are ineffective. Nitrite might be worthy of consideration as a mouth-rinse constituent.

Effect of sodium nitrite and ascorbic acid on the growth and acid production of Streptococcus mutans.

UNLABELLED: Nitrite at acid pH has been shown to be antibacterial particularly against the highly cariogenic species Streptococcus mutans. Nitrite might yield nitrosamines in vivo but ascorbic acid (vitamin C) could counteract these potential ill effects. The aim of this study is to determine whether ascorbic acid would interfere with the ability of sodium nitrite to suppress growth and acid production of S. mutans, NCTC 10449(T) and NCTC 10832. Strains were grown in Fastidious Anaerobe Broth before exposure to 200 mM nitrite in the presence of various concentrations of ascorbic acid (0.0, 5.7, 11.4, 17.0, 22.7, 28.4, 56.8, 85.2 mM). End pH was measured after 24 h exposure and cultures were serially diluted for viable counts. Statistical significance of differences in end pH values, each from 10 experiments, was determined using the Mann-Whitney U-Test. At all concentrations of ascorbic acid plus 200 mM nitrite plus S. mutans the pH was higher than with controls lacking ascorbic acid and/or nitrite (p>/=0.001). S. mutans was viable (between 4.5 x 10 (8) and 7.9 x 10 (9) cfuml (-1)) after growth in the presence of ascorbic acid at all concentrations without nitrite, whereas it was not detected when 200 mM nitrite was also present. CONCLUSIONS: ascorbic acid does not prevent the action of nitrite against S. mutans. Therefore ascorbic acid could be used in conjunction with nitrite to help counteract potential ill effects for humans.

Effects of T2-Weighted MRI Based Cranial Volume Measurements on Studies of the Aging Brain.

Many brain aging studies use total intracranial volume (TIV) as a proxy measure of premorbid brain size that is unaffected by neurodegeneration. T1-weighted Magnetic Resonance Imaging (MRI) sequences are commonly used to measure TIV, but T2-weighted MRI sequences provide superior contrast between the cerebrospinal fluid (CSF) bounding the premorbid brain space and surrounding dura mater. In this study, we compared T1-based and T2-based TIV measurements to assess the practical impact of this superior contrast on studies of brain aging. 810 Alzheimer's Disease Neuroimaging Initiative (ADNI) participants, including healthy elders and those with mild cognitive impairment (MCI) and Alzheimer's Disease (AD), received T1-weighted and T2-weighted MRI at their baseline evaluation. TIV was automatically estimated from T1-weighted images using FreeSurfer version 4.3 (T1TIV), and an automated active contour method was used to estimate TIV from T2-weighted images (T2TIV). The correlation between T1TIV and T2TIV was high (.93), and disagreement was greater on larger heads. However, correcting a FreeSurfer-based measure of total parenchymal volume by dividing it by T2TIV led to stronger expected associations with a standardized measure of cognitive dysfunction (MMSE) in Poisson regression models among individuals with AD (z=1.73 vs. 1.09) and MCI (z=3.15 vs. 2.79) than a corresponding parenchymal volume measure divided by T1TIV. This effect was enhanced when the analysis was restricted to the cases where T1TIV and T2TIV disagreed the most. These findings suggest that T2-based TIV measurements may be higher fidelity than T1-based TIV measurements, thus leading to greater sensitivity to detect biologically plausible brain-behavior associations.

Longitudinal changes in white matter disease and cognition in the first year of the Alzheimer disease neuroimaging initiative.

OBJECTIVE: To evaluate relationships between magnetic resonance imaging (MRI)-based measures of white matter hyperintensities (WMHs), measured at baseline and longitudinally, and 1-year cognitive decline using a large convenience sample in a clinical trial design with a relatively mild profile of cardiovascular risk factors. DESIGN: Convenience sample in a clinical trial design. SUBJECTS: A total of 804 participants in the Alzheimer Disease Neuroimaging Initiative who received MRI scans, cognitive testing, and clinical evaluations at baseline, 6-month follow-up, and 12-month follow-up visits. For each scan, WMHs were detected automatically on coregistered sets of T1, proton density, and T2 MRI images using a validated method. Mixed-effects regression models evaluated relationships between risk factors for WMHs, WMH volume, and change in outcome measures including Mini-Mental State Examination (MMSE), Alzheimer Disease Assessment Scale-Cognitive Subscale (ADAS-Cog), and Clinical Dementia Rating Scale sum of boxes scores. Covariates in these models included race, sex, years of education, age, apolipoprotein E genotype, baseline clinical diagnosis (cognitively normal, mild cognitive impairment, or Alzheimer disease), cardiovascular risk score, and MRI-based hippocampal and brain volumes. RESULTS: Higher baseline WMH volume was associated with greater subsequent 1-year increase in ADAS-Cog and decrease in MMSE scores. Greater WMH volume at follow-up was associated with greater ADAS-Cog and lower MMSE scores at follow-up. Higher baseline age and cardiovascular risk score and more impaired baseline clinical diagnosis were associated with higher baseline WMH volume. CONCLUSIONS: White matter hyperintensity volume predicts 1-year cognitive decline in a relatively healthy convenience sample that was similar to clinical trial samples, and therefore should be considered as a covariate of interest at baseline and longitudinally in future AD treatment trials.

The effects of an immediately pre-surgical chlorhexidine oral rinse on the bacterial contaminants of bone debris collected during dental implant surgery.

Dental implant surgery produces bone debris that can be used in the "simultaneous augmentation" technique. Although this debris is contaminated with oral bacteria, a stringent aspiration protocol has been shown to reduce the levels of contamination. Chlorhexidine mouthrinse is a well-proven antibacterial rinse that has been shown to reduce infectious complications associated with dental implants. This study examined the effect of pre-operative rinsing with a 0.1% chlorhexidine digluconate mouthrinse on the bacterial contaminants present in collected bone debris bone (CBD). Twenty partially edentate patients were randomly allocated into equal groups and underwent bone collection using the Frios Bone Collector (FBC) during the insertion of two dental implants. In group T a pre-operative chlorhexidine rinse was used, whilst in group C sterile water was used. For both groups, a stringent bone collection protocol was used. Bone samples were immediately transported for microbial analysis. Colonial and microscopic morphology, gaseous requirements and identification kits were utilised for identification of the isolated microbes. Thirty-nine species were identified including a number associated with disease, in particular Actinomyces odontolyticus, Clostridium bifermentans, Prevotella intermedia, and Propionibacterium propionicum. Samples from group T (chlorhexidine mouthrinse) yielded significantly fewer organisms (P < 0.001) than in group C (sterile water mouthrinse). Gram-positive cocci dominated the isolates from both groups. It is concluded that if bone debris is to be used for the purpose of immediate simultaneous augmentation, a preoperative chlorhexidine mouthrinse should be utilised in conjunction with a stringent aspiration protocol to reduce further the bacterial contamination of CBD.

Bone collected during dental implant surgery: a clinical and histological study.

Bone traps vary in design, although the effect of pore size on the nature of the debris collected in vivo has not yet been established. The aims of this study were 1) to compare the clinical performance of two bone collectors during implant surgery, ii) to establish the mass of tissue collected by each device, and iii) to characterize the nature of the collected debris. Thirty-eight patients (paired for implant site) were categorised into three clinical groups according to the site and the number of implants they were to receive. Patients underwent bone collection with the Frios bone trap or the Osseous Coagulum Trap according to a randomisation sequence. The samples were fixed in formalin, frozen, freeze-dried and weighed. Material from each sample was embedded in paraffin wax and stained with haematoxylin and eosin. All sections were examined by optical microscopy and the proportion of bone to coagulum was established histomorphometrically. During surgery, the Frios bone trap blocked once and the Osseous Coagulum Trap blocked 11 times. In all cases where blockage occurred, excess coagulum was apparent. All the samples that were collected by the Frios bone trap contained bone and coagulum, with a mean proportion of 90.6% bone. With regard to the Osseous Coagulum Trap, one sample contained no bone and two samples contained only trace amounts of bone; the remaining samples contained a mean proportion of 67.3% bone. Pore size affects both clinical performance and the histological composition of the debris collected, and this might have important implications if used as an augmentation material.