Adaptive spatio-temporal filtering of multichannel surface EMG signals

A motor unit (MU) is defined as an anterior horn cell, its axon, and the muscle fibres innervated by the motor neuron. A surface electromyogram (EMG) is a superposition of many different MU action potentials (MUAPs) generated by active MUs. The objectives of this study were to introduce a new adaptive spatio-temporal filter, here called maximum kurtosis filter (MKF), and to compare it with existing filters, on its performance to detect a single MUAP train from multichannel surface EMG signals. The MKF adaptively chooses the filter coefficients by maximising the kurtosis of the output. The proposed method was compared with five commonly used spatial filters, the weighted low-pass differential filter (WLPD) and the marginal distribution of a continuous wavelet transform. The performance was evaluated using simulated EMG signals. In addition, results from a multichannel surface EMG measurement fro from a subject who had been previously exposed to radiation due to cancer were used to demonstrate an application of the method. With five time lags of the MKF, the sensitivity was 98.7% and the highest sensitivity of the traditional filters was 86.8%, which was obtained with the WLPD. The positive predictivities of these filters were 87.4 and 80.4%, respectively. Results from simulations showed that the proposed spatio-temporal filtration technique significantly improved performance as compared with existing filters, and the sensitivity and the positive predictivity increased with an increase in number of time lags in the filter.     

Distribution of Common CARD15 Variants in Patients with Sporadic Crohn’s Disease: Cases from Turkey

Three common genetic variations, namely, R702W, G908R, and 1007fs, on CARD15 have been shown to increase the risk for Crohn’s disease (CD) in Caucasian populations. In this study the frequencies of these CARD15 variants were determined by genotyping in 56 patients with CD and 100 healthy ethnically matched controls from Turkey. Overall frequency of all three variants was 10.7% in CD patients, compared with 1.5% in controls (odds ratio [OR]: 7.9). Among them, the frequency of the G908R variant allele was 8% in CD cases, compared with 0% in controls (OR: 36.8). The allele frequencies of three CD-related CARD15 variants were considerably lower in the control group compared to the reported Caucasian populations. Among the described CARD15 variants, G908R confers an increased susceptibility to CD, whereas the more frequently reported associations in Europeans with R702W and 1007fs are not confirmed in this Turkish population.     

Risk Factors for the Transmission of Hepatitis C Virus Infection in the Turkish Population

The risk factors for the transmission of hepatitis C virus (HCV) infection varies substantially between countries and geographic regions. The aim of this investigation was to determine the risk factors which may be involved in the transmission of HCV infection in the Turkish population. This study included patients who were admitted to the Department of Gastroenterohepatology, Istanbul Medical Faculty, Istanbul University, between 1996 and 2002 and found to be anti-HCV positive during hospitalization or during follow-up as outpatients. All patients were asked about risk factors for HCV transmission including transfusion, history of operation, hospitalization, hemodialysis, intravenous drug use, suspected sexual contact, tattooing, acupuncture, dental procedures, manicure and pedicure, blood brotherhood rituals, perinatal risk factors, common circumcision rituals, and history of abortion. In our study, total of 320 patients with anti-HCV seropositivity were involved. The numbers and percentages of male and female patients were 139 (43.4%) and 181 (56.6%), respectively. The mean age of the patients was 49.7± 12.4 years (range: 18–73 years). HCV-RNA was found to be positive in 297 (92.8%) patients. The most common risk factor was a history of surgery (305; 98%), and the second most common was blood transfusion (123; 39.7%). The numbers and percentages of patients for the other risk factors were as follows: dental procedure, 86 (27.5%); abortion, 66 (21.2%); long-term hospitalization, 37 (11.6%); hemodialysis, 31 (10%); history of jaundice, 15 (4.6%); history of intravenous drug abuse, 10 (3.1%); history of suspected sexual contact, 5 (1.5%); history of manicure and pedicure, 4 (1.2%); history of occupational transmission, 3 (0.9%); history of tattooing, 2 (0.6%); history of acupuncture, 2 (0.6%); circumcision in a common circumcision ritual, 1 (0.3%); and percutaneous needle puncture, 1 (0.3%). None of the patients had a history of blood brotherhood ritual or perinatal transmission. Only one risk factor was detected in 73 (22.8%) patients, two risk factors were detected in 122 (38.2%) patients, three risk factors were detected in 78 (24.5%) patients, and four risk factors were detected in 39 (12.2%) patients, however, in 8 (1.6%) patients no risk factors could be found. In Turkey, the most common risk factor for the transmission of HCV infection is surgery, which can be preventable.     

Clinical presentations of chlamydial and non-chlamydial reactive arthritis

The aim of this study was to investigate the triggering micro-organisms and the clinical as well as laboratory differences between Chlamydial and non-chlamydial reactive arthritis (ReA) in a prospective study on 98 patients with acute/subacute arthritis. An inciting organism was found in 42 patients. Eighteen of these were chlamydial. Fifty-seven percent of all ReA patients were carriers for HLA-B27, which increased to 67% in the chlamydial group. Chlamydial ReA patients had more urethritis (P<0.05) with a longer period between arthritis and inciting infection, significantly lower CRP levels, and involved joint counts (P<0.05). Additionally, sacroiliitis was more frequent besides extra-articular manifestations in chlamydial ReA group. This study shows that chlamydial ReA differs in some points from non-chlamydial ReA, which in turn may affect the evaluation of an arthritic patient. ReA due to chlamydia more frequently encompasses a monoarticular or oligoarticular clinical picture with predominant distal extremity involvement. Non-chlamydial ReA presents higher joint counts and may involve upper extremity joints.     

The relation between joint erosion and generalized osteoporosis and disease activity in patients with rheumatoid arthritis

The aim of this study is to investigate the correlation between joint erosion and osteoporosis in patients with rheumatoid arthritis (RA). Fifty-one patients with RA were included for the study. Hand radiograms of all patients were evaluated by the Larsen modified Sharp and carpometacarpal ratio methods. Bone mineral density (BMD) measurements were performed at the femur, lumbar, and forearm regions. Disease activity was assessed clinically by the health assessment questionnaire (HAQ), visual analog scale, erythrocyte sedimentation rate, C-reactive protein (CRP), and the rheumatoid factor (RF). There was no statistically significant difference in terms of the BMD values at L1-4 between the patients with RA and the control group. The BMD measurements at the right forearm and the right hip were statistically significantly lower in the patient group. For radiological scoring, hand radiograms were evaluated by three different methods. There was a significant correlation between the duration of disease and the radiological evaluation methods. HAQ scores, Larsen and Sharp methods 1/3 distal and mid-distal (MID), and BMD measurements of the forearm were correlated. Moreover, 1/3 distal, MID, and ultra-distal BMD showed significant correlations with CRP levels. Radiogram continues to have an important role in determining and following-up the joint erosion seen in patients with RA. However, we believe that as establishing periarticular osteoporosis in the early term by performing BMD measurements on the forearm is correlated with disease activity, it may be useful in the early diagnosis of RA and its objective results will be efficient in predicting the progression of disease     

Psychiatric symptoms and health-related quality of life in children and adolescents with psoriasis

Information about the relationship between psoriasis and psychiatric morbidity and quality of life in children and adolescents is limited. We aimed to examine the symptoms of depression and anxiety and health-related quality of life levels in children and adolescents with psoriasis. Forty-eight outpatients with psoriasis aged 8 to 18 years are included in this study. Child Depression Inventory (CDI), State-Trait Anxiety Inventories for Children (STAI-C) and Pediatric Quality of Life Inventory Parent and Child Versions (PedQL-P and C) were applied to both patient and control groups. Psoriasis symptom severity was measured by the Psoriasis Area Severity Index (PASI). Both study and control groups were divided into two age groups, child (8-12 yrs) and adolescent (13-18 yrs), to exclude the effect of puberty on psychological condition. The mean CDI score was higher, and PedQL-C psychosocial and total scores were lower in the children compared with controls. Duration of psoriasis had an increasing effect on physical-health and total scores of PedQL-C in the child group and all PedQL-C scores in the entire sample. Psoriasis severity showed a negative correlation with psychosocial and total scores of PedQL-P in the adolescent group and PedQL-P physical-health scores in the entire sample. Psoriasis is related to depression and impaired quality of life in children. The depressive symptoms in children with psoriasis should not be overlooked and psychiatric assessment of these children should be provided.     

Hypokalemic periodic paralysis in Sjogren’s syndrome secondary to distal renal tubular acidosis

We report a 53-year-old Turkish female presented with progressive weakness and mild dyspnea. Laboratory results demonstrated severe hypokalemia with hyperchloremic metabolic acidosis. The urinary anion gap was positive in the presence of acidemia, thus she was diagnosed with hypokalemic paralysis from a severe distal renal tubular acidosis (RTA). Immunologic work-up showed a strongly positive ANA of 1:3,200 and positive antibodies to SSA and SSB. Schirmer’s test was abnormal. Autoimmune and other tests revealed Sjögren syndrome as the underlying cause of the distal renal tubular acidosis. Renal involvement in Sjogren’s syndrome (SS) is not uncommon and may precede sicca complaints. The pathology in most cases is a tubulointerstitial nephritis causing among other things, distal RTA, and, rarely, hypokalemic paralysis. Treatment consists of potassium repletion, alkali therapy, and corticosteroids. Primary SS could be a differential in women with acute weakness and hypokalemia.     

Relation of the Fas and FasL gene polymorphisms with susceptibility to and severity of rheumatoid arthritis

To investigate associations of the Fas and FasL genes polymorphisms with rheumatoid arthritis (RA). One hundred patients with RA and age-, sex- and ethnically matched 101 controls were included. Four polymorphisms of Fas (-670 A>G rs1800682, -1377 G>A rs2234767) and FasL (IVS2nt-124 A>G rs5030772, -844 T>C rs763110) genes were typed from genomic DNA. Genotype distributions and allelic frequencies were compared between patients and control subjects. After the history and clinical examination of patients with RA, in terms of pain, fatigue and general health status were evaluated by visual analogue scale. Thereafter, erythrocyte sedimentation rate, C-reactive protein, blood count and rheumatoid factor levels were measured. The Disease Activity Score-28, Health Assessment Questionnaire and modified Sharp score were used to evaluate the disease activity, functional disability and radiological damage, and their relationships with the Fas and FasL gene polymorphisms were investigated. In patients with RA, CT and TT genotypes of FasL-844, polymorphism were twofold and 4.8-fold higher, and AA genotype of FasL IVS2nt-124 polymorphism was 3.4-fold higher than the control group (respectively, p = 0.05, p = 0.002, p = 0.039). T allele of FasL-844 polymorphism was more frequent in patients than controls (respectively, 52.5 vs. 41.4 %, p = 0.027). Any association was not detected between Fas (-670 A>G, -1377 G>A) and FasL (-844 T>C, IVS2nt-124 A>G) gene polymorphisms with the disease activity scores, functional disability and radiological damage. However, the Fas-670 A>G polymorphism was associated with drug therapy (p = 0.049). The distribution of GG genotype was higher compared to GA or AA genotypes in patients using triple disease-modifying antirheumatic drug therapy (71.4, 14.3 and 14.3 %, respectively). These findings suggest that the -844 T>C and IVS2nt-124 A>G polymorphisms in the FasL gene related with apoptosis may increase genetic susceptibility to RA in a Turkish population. In addition, the Fas-670 A>G gene polymorphism may be associated with disease progression. There is a need for further studies to clarify the genetic role of apoptosis in RA.     

HBV-related events after allogeneic hematopoetic stem cell transplantatıon in a center from Turkey

To investigate the frequency of hepatitis B virus (HBV)-related events after allogeneic HCT in a moderate endemic area for HBV infection. The data of 197 patients who underwent allogeneic hematopoetic stem cell transplatation (HCT) from September 2003 through December 2010 were reviewed retrospectively with respect to HBV-related events. Resolved HBV infection was described as negative HBsAg, positive HBcAb, and positive HBsAb. Latent HBV infection was defined in patients with HBcAb positivity in the abscence of HBV DNA and HBsAb. Hepatitis B naive patients are defined as the patiens with no serological or molecular marker related to HBV. Seropositive patients were the patients with positive HBsAg and HBV-DNA. Median age was 28 (range, 15–64) years, with 128 male and 69 female patients. Median follow-up of the cohort was 8 (range, 0.5–78) months. We detected HBV-related events in 7 (3.6 %) recipients after allogeneic HCT. Five (71.4 %) of these events were HBV reactivation, while two cases (28.6 %) had acute hepatitis B infection. Four of the five reactivations were in the seropositive group (80 %), while one ocurred in a patient with resolved hepatitis. Two patients who developed acute hepatitis B were HBV naive and previously immunized patients, respectively. Hepatitis B virus reactivation remains a problem in seropositive patients and might require more effective treatment strategies.