Fragmented QRS encompasses different RSR’ patterns showing various morphologies of the QRS complexes with or without the Q wave on a resting 12-lead electrocardiogram. It has been shown possibly to cause adverse cardiac outcomes in patients with some heart diseases, including coronary artery disease. In view of the need for risk stratification of patients presenting with acute coronary syndrome in the most efficacious and cost-effective way, we conducted this study to clarify the value of developing fragmented QRS in a cohort of patients presenting with their first acute coronary syndrome in predicting 6-month mortality and morbidity.
One hundred consecutive patients admitted to the coronary care unit at Shahid Madani Heart Center in Tabriz from December 2008 to March 2009 with their first acute coronary syndrome were enrolled in this prospective study. Demographic and electrocardiographic data on admission, inhospital mortality, and need for revascularization were recorded. Electrocardiography performed 2 months after the index event was examined for development of fragmented QRS. Mortality and morbidity was evaluated at 6-month follow-up in all patients.
The patients were of mean age 57.7 ± 12.8 years, and 84% were men. The primary diagnosis was unstable angina in 17 (17%) patients, non-ST elevation myocardial infarction (MI) in 11 (11%), anterior or inferior ST elevation MI in 66 (66%), and postero-inferior MI in six (6%). Fragmented QRS was present in 30 (30%) patients during the first admission, which increased to 44% at the 2-month follow-up and to 53% at the 6-month follow-up. The presence of various coronary risk factors and drug therapy given, including fibrinolytic agents, had no effect on development of fragmented QRS. Mortality was significantly higher (P = 0.032) and left ventricular ejection fraction was significantly lower (P = 0.001) in the fragmented QRS group at the 6-month follow-up.
This study strongly suggests that fragmented QRS on initial presentation with acute coronary syndrome is not predictive of subsequent events but, if present 6 months later, could be predictive of an adverse outcome.
acute coronary syndrome; fragmented QRS; electrocardiography; mortality; left ventricular function
Genetic and environmental factors are important for the development of nonalcoholic fatty liver disease (NAFLD). Adiponectin is a white and brown adipose tissue hormone, and have been found to play essential roles in the regulation of energy homoeostasis. Recent reports have identified a possible role of adiponectin in NAFLD via PPARγ pathway.
The present study was designed to find out the impact of adiponectin rs1501299 (276G/T) and rs266729 (-11377C/G) gene polymorphisms in NAFLD.
Patients and Methods
Eighty-three patients with diagnosis of NAFLD, and 93 healthy subjects were included in the study. Tetra ARMS-PCR was designed to detect single nucleotide polymorphisms.
A significant difference was found between NAFLD and control group regarding the rs266729 polymorphism (χ2 = 7.35, P = 0.025). The rs266729 polymorphism increased the risk of NAFLD in codominant (CC vs. CG: OR = 2.18, 95% CI = 1.16 - 4.12, P = 0.016) and dominant (CC vs. CG/GG: OR = 2.31, 95% CI = 1.25 - 4.27; P = 0.008) inheritance tested models. The G allele increased the risk of NAFLD (OR = 1.63, 95% CI = 1.03 - 2.57, P = 0.037) in comparison with C allele. No significant difference was found between the groups concerning adiponectin rs1501299 gene polymorphism (χ2 = 0.70, P = 0.697).
adiponectin rs266729 polymorphism might be a candidate gene, which determines the susceptibility to NAFLD. Larger studies are necessary to confirm these findings in various populations.
Fatty Liver; Adiponectin; Polymorphism
Background: The protein of Niemann-pick type C1 (NPC1) gene promotes the egress of cholesterol from late endosomes and lysosomes to other cellular compartments and contributes to a process known as reverse cholesterol transport. This study aimed to examine whether promoter methylation of NPC1 is associated with risk of cardiovascular disease (CVD). Methods: Fifty CVD patients and 50 healthy subjects as the control group were recruited in this study. Promoter methylation of NPC1 gene was defined using a nested-methylation specific polymerase chain reaction method. Statistical analyses were done using the chi-square, t-test or ANOVA tests. Results: Our study showed that the frequency of semi-methylated promoter (methylated/unmethylated status) was significantly higher in CVD patients than that in controls (OR = 6.521, 95% CI = 2.211-19.215, P = 0.008). However, a completely methylated promoter (methylated/methylated status) was not detected in any subjects in either of the two groups tested. Additionally, the analysis of clinical data according to the methylation status of NPC1 gene demonstrated that serum levels of total cholesterol, total triglycerides, high low-density lipoprotein cholesterol (LDL-C) and low high-density lipoprotein cholesterol (HDL-C) are influenced by NPC1 methylation, so that subjects with a completely unmethylated promoter (Unmethylated/unmethylated status) held lower levels of total triglycerides, total cholesterol, LDL-C and higher levels of HDL-C. Conclusion: Our findings propose that the NPC1 promoter methylation is a probable mechanism that can result in reduced/impaired NPC1 expression/activity and may thus contribute to progression of CVD.
Niemann-pick type C1 (NPC1); Promoter methylation; cardiovascular disease
To investigate the effect of promoter methylation of cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) gene and matrix metalloproteinases (MMPs) on the risk of non-alcoholic fatty liver disease (NAFLD).
MATERIALS AND METHODS:
CTLA-4 and MMP-9 promoter methylation were investigated using a methylation-specific polymerase chain reaction (MS-PCR) in blood samples taken from 80 NAFLD individuals and 95 healthy controls. The expression levels of CTLA-4 and MMP-9 were also assessed in 10 blood and 9 liver tissues mRNA samples from NAFLD patients. These cases were compared to the blood (n = 10) samples of healthy controls with real-time quantitative reverse transcriptase PCR.
No significant relationship was found for methylation of CTLA-4 and MMP-9 between cases and controls. The relative expression of CTLA-4 and MMP-9 mRNA in NAFLD was not significantly different compared to healthy control samples.
For the first time, our outcomes indicate that the methylation status of CTLA-4 and MMP-9 genes has no significant function on the process of NAFLD.
Cytotoxic T-lymphocyte-associated antigen-4; expression; gene; methylation; matrix metalloproteinases-9; non-alcoholic fatty liver disease
Biological Markers; Alpha 1 Antitrypsin; lobaplatin; Aflatoxins; Hepatitis B Virus; Hepatitis C
Fas/Fas ligand (FasL) system is one of the key apoptotic signaling entities in the extrinsic apoptotic pathway. De-regulation of this pathway, i.e. by mutations may prevent the immune system from the removal of newly-formed tumor cells, and thus lead to tumor formation. The present study investigated the association between −1377 G/A (rs2234767) and −670 A/G (rs1800682) polymorphisms in Fas as well as single nucleotide polymorphisms INV2nt −124 A/G (rs5030772) and −844 C/T (rs763110) in FasL in a sample of Iranian patients with breast cancer. This case-control study was done on 134 breast cancer patients and 152 normal women. Genomic DNA was extracted from whole blood samples. The polymorphisms were determined by using tetra-ARMS-PCR method. There was no significant difference in the genotype distribution of FAS rs2234767 polymorphism between cases and controls. FAS rs1800682, FASL rs5030772, and FASL rs763110 genotypes showed significant associations with an increasing risk of breast cancer (odds ratio OR = 3.18, P = 0.019; OR = 5.08, P = 0.012; OR = 2.40, P = 0.024, respectively). In conclusion, FAS rs2234767 was not associated with breast cancer risk. Though, FAS rs1800682, FASL rs5030772, and FASL rs763110 polymorphisms were associated with the risk of breast cancer in the examined population.
Hypertension is a major risk factor for cardiovascular diseases. It affects approximately 18.0% of Iranian adults. This study aimed to estimate age-adjusted prevalence of hypertension and its control among Iranian persons older 19 years of age. It also tried to find and socioeconomic factors associated with hypertension control in Iranian population.
In Isfahan Healthy Heart Program (IHHP) subjects were selected by multistage random sampling. The participants completed questionnaires containing demographic information, lifestyle habits, medical history, and consumption of relevant medications, especially antihypertensive agents. Income, marital status, and educational level were considered as socioeconomic factors. Hypertension was defined as systolic blood pressure ≥ 140 mmHg, diastolic blood pressure ≥ 90 mmHg, or taking antihypertensive medications. Controlled hypertension was considered as systolic blood pressure < 140 mmHg and diastolic blood pressure < 90 mmHg among hypertensive subjects.
The prevalence of hypertension and controlled hypertension was 18.9% and 20.9%, respectively. We found significant relationships between hypertension and marital status, education, and income. At age ≥ 65 years old, odds ratio (OR) was 19.09 [95% confidence interval (CI): 15.01-24.28] for hypertension. Middle family income (OR: 0.71; 95% CI: 0.58-0.87) and education level of 6-12 years (OR: 0.29; 95% CI: 0.25-0.35) were significantly associated with increased risk of hypertension (P = 0.001). Among subjects aging 65 years old or higher, the OR of controlled hypertension was 2.64 (95% CI: 1.61-4.33). Married subjects had a higher OR for controlled hypertension (OR: 2.19; 95% CI: 1.36-3.52). Obesity had no significant relationships with controlled hypertension.
The IHHP data showed significant relationships between some socioeconomic factors and controlled hypertension. Therefore, as current control rates for hypertension in Iran are clearly unacceptable, we recommend preventive measures to control hypertension in all social strata of the Iranian population.
Socioeconomic Factor; High Blood Pressure; Control
Tuberculosis (TB) is a major cause of morbidity and mortality worldwide. IRGM1 is an important protein in the innate immune response against intracellular pathogens by regulating autophagy. Polymorphisms in the IRGM genes are known to influence expression levels and may be associated with outcome of infections. This case-control study was done on 150 patients with PTB and 150 healthy subjects to determine whether the IRGM polymorphisms at positions −1208 A/G (rs4958842), −1161 C/T (rs4958843), and −947 C/T (rs4958846) were associated with PTB. The polymorphisms were determined using tetra-amplification refractory mutation system-PCR (T-ARMS-PCR). The results showed that the IRGM −1161 C/T and −947 C/T polymorphisms were associated with decreased susceptibility to PTB (OR = 0.06, 95% CI = 0.03–0.13, P < 0.001 and OR = 0.27; 95% CI = 0.013–0.55, P < 0.001, resp.). No significant difference was found among the groups regarding −1208 A/G polymorphism. In conclusion we found that the IRGM −1161 C/T and −947 C/T polymorphisms but not −1208 A/G polymorphism provide relative protection against PTB in a sample of Iranian population.
Introduction. The association of diabetes and atherosclerosis with disorders of lipids and lipoproteins, notably high apolipoprotein B (apoB) and low apolipoprotein A1(apoA1) is well established. Because of the beginning of the atherosclerosis' process from early life, in this study, the plasma levels of apoA1 and apoB were compared in diabetic children with type I diabetes mellitus(DM), healthy children with diabetic parents (HDPs),and healthy children with nondiabetic parents (HNDPs). Methods. This case-control study was conducted among 90 children aged 9–18 years. Serum levels of apoA and apoB were compared among 30 diabetic children (DM), 30 healthy children with diabetic parents (HDPs), and 30 healthy children with nondiabetic parents (HNDP). Results. The mean serum apoA1 was higher in DM (153 ± 69 mg/dL) followed by HNDPs (138 ± 58 mg/dL) and HDPs (128 ± 56 mg/dl), but the difference was not statistically significant. The mean apoB value in HNDPs was significantly lower than DM and HDPs (90 ± 21 mg/dL versus 127 ± 47 and 128 ± 38 mg/dL, P < 0.05, respectively). The mean apoB levels in DM (127 ± 47 mg/dl) and HDP (128 ± 38 mg/dL) were not statistically significantly different (P > 0.05). Conclusions. Diabetic children and healthy children with diabetic parent(s) are at higher risk of dyslipidemia and atherosclerosis. Thus for primordial and primary prevention of atherosclerosis, we suggest screening these children for low plasma apoA1 and high plasma apoB levels.
Lack of heart rate increase proportionate to exercise causes poor prognosis. Moreover, inflammatory factors such as C-reactive protein (CRP) are associated with atherosclerosis. The current study compared these two indices in individuals with and without metabolic syndrome in Isfahan, Iran.
This study was performed on 203 people without and 123 patients with metabolic syndrome who were randomly selected from the participants of the Isfahan Cohort Study. The demographic data, waist circumference, blood pressure, height, and weight of the participants were recorded. Moreover, serum tr`viglyceride (TG), fasting blood sugar (FBS), total cholesterol, high density lipoprotein (HDL), low density lipoprotein (LDL), and high-sensitivity CRP (hs-CRP) levels were measured. Exercise test was carried out according to the Bruce standard protocol and heart rate reserve (HRR) was determined and recorded. The age-adjusted data was analyzed using generalized linear regression and student's t-test in SPSS15.
The mean ages of participants without and with metabolic syndrome were 54.16 ± 8.61 and 54.29 ± 7.6 years, respectively. The corresponding values for mean LDL levels were 116.17 ± 24.04 and 120.12 ± 29.55 mg/dl. TG levels were 140.38 ± 61.65 and 259.99 ± 184.49 mg/dl for subjects without and with the metabolic syndrome, respectively. The mean FBS levels were 81.81 ± 9.90 mg/dl in the participants without the syndrome and 107.13 ± 48.46 mg/dl in those with metabolic syndrome. The mean systolic blood pressure was 116.06 ± 13.69 mmHg in persons without metabolic syndrome and 130.73 ± 15.15 mmHg in patients with the syndrome. The values for mean diastolic levels in the two groups were 76.52 ± 6.69 and 82.84 ± 8.7 mmHg, respectively. While the two groups were not significantly different in terms of HRR (P = 0.27), hs-CRP levels in the metabolic syndrome group was significantly higher than the other group (P = 0.02).
We failed to establish a relationship between HRR and the metabolic syndrome. However, the observed relationship between metabolic syndrome and hs-CRP level, which is an inflammatory factor, indicates elevated levels of hs-CRP in patients with metabolic syndrome.
Metabolic Syndrome; Exercise Test; Heart Rate Reserve; High-Sensitivity C-Reactive Protein
This study aimed to determine the association of particulate matters with endothelial function, measured by flow mediated dilation (FMD) of brachial artery, in children with or without exposure to secondhand smoke.
This cross-sectional study was conducted from January to March 2011 in Isfahan, which is the second large and air-polluted city in Iran. The areas of the city with lowest and highest air pollution were determined, and in each area, 25 prepubescent boys with or without exposure to daily tobacco smoke in home were selected, i.e. 100 children were studied in total.
FMD was significantly smaller in those living in high-polluted area and those exposed to secondhand smoke. Multiple linear regression analysis, adjusted for age and body mass index, showed that both passive smoking status and living area in terms of particulate air pollution were effective determinants of the brachial artery diameter. The standardized coefficient of passive smoking status was –0.36 (SD = 0.09, P < 0.0001) showing negative association with percent increase in FMD. Likewise, the percent increase in brachial artery diameter was lower in passive smoker children. Similar relationship was documented for PM10 concentration with a regression coefficient of –0.32 (SD = 0.04, P < 0.0001). Without considering passive smoking variable, PM10 concentration has significant independent effect on FMD level.
Our findings provide evidence on the association of environmental factors on endothelial dysfunction from early life. Studying such associations among healthy children may help identify the underlying mechanisms. The clinical implications of environmental factors on early stages of atherosclerosis should be confirmed in longitudinal studies.
Air pollution; children; endothelium-dependent brachial artery; smoke
It has been shown that some opium derivatives promote cell death via apoptosis. This study was designed to examine the influence of opium addiction on brain and liver cells apoptosis in male and female diabetic and non-diabetic Wistar rats. This experimental study was performed on normal, opium-addicted, diabetic and diabetic opium-addicted male and female rats. Apoptosis was evaluated by TUNEL and DNA fragmentation assays. Results of this study showed that apoptosis in opium-addicted and diabetic opium-addicted brain and liver cells were significantly higher than the both normal and diabetic rats. In addition, we found that apoptosis in brain cells of opium-addicted and diabetic opium-addicted male rats were significantly higher than opium-addicted and diabetic opium-addicted female, whereas apoptosis in liver cells of opium-addicted and diabetic opium-addicted female rats were significantly higher than opium-addicted and diabetic opium-addicted male. Overall, these results indicate that opium probably plays an important role in brain and liver cells apoptosis, therefore, leading neurotoxicity and hepatotoxicity. These findings also in away possibly means that male brain cells are more susceptible than female and interestingly liver of females are more sensitive than males in induction of apoptosis by opium.
Addiction; Apoptosis; Brain cells; Diabetes; Liver cells
Conventional angiography, generally referred to as intra-arterial digital subtraction angiography, still remains the gold standard reference method for the diagnosis of intracranial aneurysms, helical computed tomography angiography (CTA) is a new non-invasive volumetric imaging method.
This study was conducted to screen patients presenting with subarachnoidhemorrhage by CTA before conventional digital subtraction angiography (DSA) and subsequently comparing the results for various aneurysm projections.
Patients and Methods
In a prospective study, 99 consecutive patients with an initial diagnosis of subarachnoid hemorrhage were screened for aneurysms with CTA followed by conventional DSA. There were 17 cases with negative angiograms in whom repeat angiograms, three months later were negative for 15 cases, while two cases were found to bear aneurysm on the repeat examination. Eighty two patients had at least one proven aneurysm on initial DSA and two on the repeat angiogram. Out of 84 patients, five underwent endovascular treatment and 79 patients who underwent surgical clipping were considered for projection evaluation.
Sensitivity of CTA was 98.78% (95% confidence interval [CI], 93.4-99.7%), while the specificity was 100% (95% CI, 81.57-100%) and the kappa coefficient of agreement between CTA and DSA was 96.5%. The most significant discrepancies with DSA findings were for visualizing the projection of inferior and posterior projecting proximal anterior circulation aneurysms.
Helical CTA was in good concordance with DSA for screening of cerebral aneurysms; however, for exact visualization of the aneurysm neck and its projection, especially if it is inferior or posterior, DSA remains the gold standard.
Angiography; Digital Subtraction; Helical CT; Intracranial Aneurysm
It is important to know the spatial extent of neural activation around the stimulating electrodes when using extracellular electrical stimulation to determine the structure and function of neural circuit connections or for the restoration of function. The current-distance relationship quantifies the relationship between the threshold current for excitation of a neuron, Ith, and the distance between the electrode and the neuron, r, with two parameters: the offset, Io, and the current-distance constant, k, with a quadratic equation, Ith(r) = Io + k r 2. We proposed a new method to determine the parameters of the current-distance relationship, and thereby estimate the spatial extent of activation, based on the refractory interaction technique. Refractory interaction is a method that exploits the interaction between the regions of activation produced by two electrodes, when the second stimulus is delivered while neurons activated by the first electrode are in their refractory period. Computer simulations of electrical stimulation of a population of nerve fibers were used to determine the accuracy of the method. The mean relative error in k was 19% and in I0 was 17 %, and the spatial extent of stimulation could be determined with an absolute error of 19 μm and a relative error less than 11%. Subsequently the method was applied to measure the current-distance properties of peripheral motor nerve fibers and indicated that k = 27 μA/mm2 and I0 = 49 μA. This method provided robust estimates of the current-distance properties, and provides a means to determine the spatial extent of activation by extracellular stimulation.
electrical stimulation; current-distance relationship; spatial selectivity; refractory period; electrode array
BACKGROUND AND OBJECTIVES:
Analysis of the role of different alleles of human leukocyte antigen (HLA) in rheumatoid arthritis (RA) patients is necessary in many populations and geographical areas. The aim of the present study was to investigate the frequency of HLA-DRB1 alleles in RA patients, comparing with that in control group in southeast Iran.
DESIGN AND SETTING:
Case-control study of rheumatoid arthritis patients referred to rheumatology clinic at university hospital.
PATIENTS AND METHODS:
The frequency of HLA-DRB1 alleles was determined in 79 RA patients and 93 healthy subjects in Zahedan, southeast Iran. HLA-DRB1 allele types were identified by polymerase chain reaction with sequence-specific primer (PCR-SSP).
The HLA-DRB1*10 allele showed a significantly higher frequency in patients with RA (OR=2.698, 95% CI=1.087-6.699, P=.045), while the frequency of DRB1*03 allele in these subjects was significantly lower than that in the control group (OR=0.447, 95% CI=0.2285-0.8729, P=.021). The frequencies of DRB1*01, DRB1*04, DRB1*07, DRB1*09, DRB1*11, DRB1*13, DRB1*14, DRB1*15, DRB1*16 were not significantly different between RA subjects and the control group.
The data suggest that the DRB1*10 allele is a risk factor and DRB1*03 is protective for RA in this population.
Liver transplantation; Alpha fetoproteins; Glypican-3
This study aimed to determine the short- and long-term effects of consumption of grape and pomegranate juices on markers of endothelial function and inflammation in adolescents with metabolic syndrome (MetS).
In a non-pharmacologic randomized controlled trial, 30 individuals were randomly assigned to two groups of drinking natural grape or pomegranate juice for 1 month. Measurements of inflammatory factors [Hs-CRP, sE-selectin, sICAM-1, sVCAM, and interleukin 6 (IL-6)] and flow-mediated dilation (FMD) were made at baseline, 4 hours after first juice consumption and after one month of juice consumption.
The percent changes of FMD were significant in both groups in the short- and long-term. Hs-CRP had a nonsignificant decrease. sE selectin had a significant decrease after 4 hours in total and in the pomegranate juice group, followed by a significant decrease after 1 month in both groups. After 4 hours, sICAM-1 significantly decreased in the pomegranate juice group, and after 1 month it decreased in total and pomegranate juice group. Interleulkin-6 (IL-6) had a significant constant decrease at 4-hour and 1-month measurements after drinking pomegranate juice, and in both groups after 1 month. Significant negative correlations of changes in sICAM-1 and sE-selectin with changes in FMD were found in both periods of follow-up; and at 1 month for IL-6.
Decline in inflammation was associated with improvement in FMD without changes in conventional risk factors. Daily consumption of natural antioxidants may improve endothelial function in adolescents with MetS.
Endothelium function; metabolic syndrome; antioxidants; inflammation; adolescents
Recent studies have confirmed inflammatory factors and metabolic syndrome (MetS) as important cardiovascular disease (CVD) risk factors. Recently measurement of carotid intima-media thickness (IMT) has been used for evaluation of early atherosclerosis. This study was designed to assess the correlation between IMT with some inflammatory biomarkers, ghrelin and adiponectin in people with and without MetS in a cohort sample in Isfahan province.
Among participants of Isfahan Cohort Study (ICS) by random sampling, 88 participants were selected and divided into case (with MetS) and control (without MetS) groups. A questionnaire including demographic data and CVD risk factors was completed for all of the participants. Physical examination and blood pressure, height, weight and waist circumference measurements were done for all subjects. Vascular echocardiography was done for evaluation of IMT of each carotid artery of both sides. Interlukin-6 (IL-6), interlukin-10 (IL-10), highly sensitive C-reactive protein (hs-CRP), ghrelin and adiponectin levels were measured using ELIZA method. Data were entered in SPSS15 software and analyzed by t-test, chi square, Pearson correlation and linear regression analyze.
The mean waist circumference, BMI, systolic blood pressure, diastolic blood pressure, hs-CRP and IMT of left carotid artery were significantly higher in participants with Mets. There was significant correlation between left carotid IMT and IL-6 level in all patients (P = 0.03). After adjustment for age and sex, significant relationship in groups with MetS was only reported between the left IMT and IL-6 (P = 0.02). There was no relation between IMT and other inflammatory markers in subjects with and without MetS.
Significant correlation between IL-6 and IMT was reported in patients with MetS. While no significant correlation between IL-10, adiponectin and ghrelin with IMT was observed in metabolic syndrome group.
Intima-media thickness (IMT); Carotid artery; hs-CRP; Ghrelin; Adiponectin IL-6; IL-10
The complex formed by two members of the S100 calcium-binding protein family, S100A8/A9, exerts apoptosis-inducing activity against various cells, especially tumor cells. Here, we present evidence that S100A8/A9 also has cell growth-promoting activity at low concentrations. Both RAGE gene silencing and co-treatment with a RAGE-specific blocking antibody revealed that this activity was mediated via RAGE ligation. In order to investigate the signaling pathways, MAP-kinase phosphorylation and NF-κB activation was characterized in S100A8/A9 treated cells. S100A8/A9 caused a significant increase in p38-MAP and p44/42 kinase phosphorylation while the status of SAPK/JNK phosphorylation remained unchanged. Treatment of cells with S100A8/A9 also enhanced NF-κB activation. RAGE siRNA pretreatment abrogated the S100A8/A9-induced NF-κB activation. Our data indicate that S100A8/A9-promoted cell growth occurs through RAGE signaling and activation of NF-κB.
S100A8/A9; RAGE; NF-κB; proliferation; MAP-Kinase
Knowing of the spatial extent of neural activation around extracellular stimulating electrodes is necessary to ensure that only the desired neurons are activated or to determine which neurons are responsible for an observed response. Various approaches have been used to estimate the current-distance relationship and thereby the spatial extent of activation resulting from extracellular stimulation. However, these approaches all require underlying assumptions and simplifications, and since the actual extent of activation cannot be directly measured, the impact of deviations from these assumptions cannot be determined. We implemented a computer-based model of excitation of a population of nerve fibers and used the model to evaluate a range of approaches proposed for measuring the spatial extent of neural activation. The estimates with each method were compared with measurements of the true spatial extent of activation that were accessible in the simulations to quantify the accuracy of the estimates and to determine the dependence of accuracy on measurement parameters (interelectrode distance, stimulation amplitude, noise). A newly proposed method, based on the refractory interaction technique, provided the most accurate and most robust estimates of the spatial extent of neural activation.
electrical stimulation; current distance relationship; spatial selectivity; nerve model
Primary intraosseous meningiomas are uncommon. The osteolytic variants of these tumors are even rarer. When one reviews a bony skull lesion, the differential diagnosis is very wide and includes both malignant and benign diseases. In case of primary skull meningioma, correct diagnosis and total resection of the lesion ensures curative therapy. Presented is a case of osteolytic skull lesion not invading the dura that was proved to be a fibrillary meningioma with regions of syncitial pattern.
Capillary hemangiomas of spinal nerve root, mostly affecting the cauda equina, are extremely rare.
A 20-year old man was presented with back pain, radiculopathy, and urogenital symptoms. Magnetic resonance images revealed an intradural extramedullary mass, isointense in T1-weighted and hyperintense in T2-weighted images, with noticeable post injection enhancement. The clinical and radiological findings simulated neurinoma.
However, a pinkish lesion was removed surgically and histopathological examination revealed lobules of capillary vessels separated by fibrous tissue, suggesting capillary hemangioma.
Although rare and sometimes indistinguishable from more common lesion, capillary hemangioma should be in differential diagnosis of any enhancing intradural extramedullary mass at the level of cauda equina or conus medullaris.
Traditionally, surgery of the anterior circulation aneurysms of the cerebral vasculature is dictated by the site of the lesion, excluding such midline lesions as anterior communication artery aneurysms. Few reports address the issue of using a single craniotomy to obliterate multiple aneurysms located in both hemispheres.
A 51 year-old Caucasian right handed housewife lady (weight 61 kg, height 159 cm) presented with a headache of acute onset which proved to be caused by acute subarachnoid hemorrhage. Cerebral computed tomographic angiography revealed multiple aneurysms. The patient underwent a right pterional craniotomy to obliterate right middle cerebral, distal basilar and left carotid bifurcation aneurysms. The post-operative course was uneventful.
Despite technical difficulties of approaching cerebral vasculature through a contralateral craniotomy, this policy is advised in selected cases in which the benefits of unilateral craniotomy outweigh the risks of brain retraction.
Nongalenic intradural arteriovenous fistulas, although uncommon, are clinically important. Choosing the appropriate therapeutic approach has been a controversial issue within the last decade.
A 15-year-old male was presented with a calcified nongalenic arteriovenous fistula in the left parietal region, supplied by the left middle cerebral artery, and draining into the left lateral sinus. The patient was managed surgically with traditional clipping the feeder artery, along with piecemeal resection of the huge calcified mass. Although endovascular methods may be the treatments of choice in similar cases, in such huge calcified lesion, non-amenable to endovascular occlusion, open surgery seems to be preferred.
Schwannoma is a rare tumor among pancreatic neoplasms. Schwannomas vary in size, and most of them are cystic, mimicking pancreatic cystic lesions. Generally, a definitive diagnosis is made at the time of histological analysis. The mainstay treatment is surgical resection.
We report an unusual presentation of pancreatic schwannoma with abdominal pain and several episodes of cholangitis in a 54-year-old Caucasian (Iranian) man. The condition was not diagnosed pre-operatively and Whipple's procedure was performed.
Pancreatic schwannoma is an important clinical entity to include in the differential diagnosis of pancreatic lesions. Pre-operative diagnosis is difficult but computed tomographic findings may be helpful. The tumor may also have atypical and rare presentations, such as cholangitis and weight loss. For benign tumors, simple enucleation is usually adequate, whereas malignant tumors require standard oncological resection.