Effects of electrical stimulation in C2C12 muscle constructs

Electrical stimulation affects the deposition of extracellular matrices and cellular differentiation. Type I collagen is one of the most abundant extracellular matrix proteins; however, not much is known about the effects of electrical stimulation on collagen type I deposition in C2C12 cells. Thus, we studied the effects of electrical voltage and stimulation frequency in 3D cultured C2C12 muscle cells in terms of metabolic activity, type I collagen deposition and cell morphology. Electrically excitable C2C12 muscle cells were seeded in collagen scaffolds and stimulated with rectangular signals of voltage (2, 5, 7 V) and frequency (1, 2 Hz), using parallel carbon electrodes spaced 1 cm apart. Metabolic activity was quantified by the glucose:lactate concentration ratio in the medium. Apoptotic activity was assessed by TUNEL staining and changes in collagen deposition were identified by immunohistology. The ultrastructure of the tissue was examined by TEM. Glucose and lactate analysis indicated that all groups had similar metabolic activity. TUNEL stain showed no significant difference in apoptotic damage induced by electrical stimulation compared to the control. Samples stimulated at 2 Hz exhibited reduced collagen deposition compared to the control and 1 Hz stimulated samples. Muscle-protein marker desmin was highly expressed in constructs stimulated with 1 Hz/5 V sample. TEM revealed that the stimulated samples developed highly organized sarcomeres, which coincided with improved contractile properties in the 1 Hz/5 V- and 2 Hz/5 V-stimulated groups. Our data implicate that a specific electrical frequency may modulate type I collagen accumulation and a specific voltage may affect the differentiation of muscle sarcomeres in excitable cells.     

Microalbuminuria in children with vesicoureteral reflux

Vesicoureteral reflux (VUR) is a common congenital anomaly of the urinary tract that may be inherited. Reflux of infected urine may cause scarring in susceptible kidneys with the potential to compromise renal function. The aim of the study was to evaluate the possible influence of different grades of VUR on glomerular damage using microalbuminuria as a parameter. Children with VUR detected by voiding cystourethrography (VCUG) were investigated. According to the grade of VUR, patients were separated into three groups. The first group included 12 children with VUR grade I-II. The second group consisted of 12 children with grade III of VUR. Patients with VUR grade IV-V (n = 11) were members of the third group. The control group consisted of 17 healthy children. Microalbuminuria was examined in samples of morning urine specimens using a microalbumin/creatinine reagent kit. Serum urea, creatinine levels and creatinine clearance (CCR) were measured as markers of renal function. The mean value of microalbumin excretion in the third group showed a statistically significant increase (p < 0.001) compared to all other groups. CCR in the third group was statistically significantly decreased (p < 0.05) in comparison to the group of healthy children. There were no statistically significant changes of microalbumin excretion and CCR in the first and second group compared to control values. We discussed the presence of microalbuminuria and decrease of CCR in children with high grade of VUR as a possible consequence of retrograde urine flow (intrarenal reflux), glomerulosclerosis, and consecutive hyperfiltration.     

Generalized regression neural networks in prediction of drug stability

This study had two aims. Firstly, we wanted to model the effects of the percentage of Eudragit RS PO and compression pressure as the most important process and formulation variables on the time course of drug release from extended-release matrix aspirin tablets. Secondly, we investigated the possibility of predicting drug stability and shelf-life using an artificial neural network (ANN). Ten types of matrix aspirin tablets were prepared as model formulations and were stored in stability chambers at 60 degrees C, 50 degrees C, 40 degrees C and 30 degrees C and controlled humidity. Samples were removed at predefined time points and analysed for acetylsalicylic acid (ASA) and salicylic acid (SA) content using stability-indicating HPLC. The decrease in aspirin content followed apparent zero-order kinetics. The amount of Eudragit RS PO and compression pressure were selected as causal factors. The apparent zero-order rate constants for each temperature were chosen as output variables for the ANN. A set of output parameters and causal factors were used as training data for the generalized regression neural network (GRNN). For two additional test formulations, Arrhenius plots were constructed from the experimentally observed and GRNN-predicted results. The slopes of experimentally observed and predicted Arrhenius plots were tested for significance using Student's t-test. For test formulations, the shelf life (t(95%)) was then calculated from experimentally observed values (t(95%) 82.90 weeks), as well as from GRNN-predicted values (t(95%) 81.88 weeks). These results demonstrate that GRNN networks can be used to predict ASA content and shelf life without stability testing for formulations in which the amount of polymer and tablet hardness are within the investigated range.     

Frequency analysis and clinical characterization of different types of spinocerebellar ataxia in Serbian patients.

The relative frequencies of different spinocerebellar ataxias (SCAs) vary widely among different ethnic groups, presumably due to a founder effect. We investigated the relative prevalence of SCA1-3, 6-8, 12, 17; dentate-rubro-pallidoluysian atrophy; and Friedreich's ataxia (FRDA) in Serbian patients with adult-onset (>20 years of age) hereditary and sporadic SCAs, and compared clinical features of patients with genetically confirmed SCAs. A total of 108 patients from 54 families (38 apparently dominant [ADCA] and 16 apparently recessive) with adult-onset hereditary ataxia and 75 apparently sporadic patients were assessed. Of 38 families with ADCA, 13 (34%) were positive for an expansion in an SCA1 and 5 families (13%) for an expansion in an SCA2 allele. In 20 families (53%), no expansions have been identified in any of the analyzed genes. Gaze palsy, spasticity, and hyperreflexia were significantly more common in SCA1, whereas slow saccades, hypotonia, hyporeflexia, and dystonia prevailed in SCA2 patients. Among the 16 families with an apparently recessive mode of ataxia inheritance, 4 (25%) were identified as having the FRDA mutation. Ataxia-causing mutations were identified in 8 (10.6%) of patients with apparently sporadic adult-onset ataxia.     

Multiple reference tissue method for contrast agent arterial input function estimation.

A precise contrast agent (CA) arterial input function (AIF) is important for accurate quantitative analysis of dynamic contrast-enhanced (DCE)-MRI. This paper proposes a method to estimate the AIF using the dynamic data from multiple reference tissues, assuming that their AIFs have the same shape, with a possible difference in bolus arrival time. By minimizing a cost function, one can simultaneously estimate the parameters and underlying AIF of the reference tissues. The method is computationally efficient and the estimated AIF is smooth and can have higher temporal resolution than the original data. Simulations suggest that this method can provide a reliable estimate of the AIF for DCE-MRI data with a moderate signal-to-noise ratio (SNR) and temporal resolution, and its performance increases significantly as the SNR and temporal resolution increase. As demonstrated by its clinical application, sufficient reference tissues can be easily obtained from normal tissues and subregions segmented from a tumor region of interest (ROI), which suggests this method can be generally applied to cancer-based DCE-MRI studies to estimate the AIF. This method is applicable to general kinetic models in DCE-MRI, as well as other CE imaging modalities.     

Optimal surgical treatment for bilateral multinodular goitre

Objective: In the present study, we compared subtotal thyroidectomy (STT) with total thyroidectomy (TT) in the management of bilateral multinodular goitre. Methods: A total of 204 consecutive patients with bilateral multinodular goitre were assigned to have either TT (n = 73) or STT (n = 131). Demographic details, hospital stay, biochemical findings, indications for operation and complications were noted. Results: There was no significant difference in the age and sex ratio between the two groups (P = 0.695 and P = 0.733). According to thyroid functional status, the majority of patients were euthyroid in both groups (73.28%vs 84.90%). Goitre grades II and III presented the most common indication for STT and TT. Hospital stay for patients who underwent TT was significantly longer compared to STT (P < 0.001). There was no significant difference in the rate of permanent complications. Conclusions: In the present study, we have shown that the risk of permanent complications with TT is no greater than with STT.     

Coexistence of Unverricht-Lundborg disease and congenital deafness: Molecular resolution of a complex comorbidity

Purpose :  We report on genetic analysis of a complex condition in a Serbian family of four siblings, wherein two had progressive myoclonic epilepsy (PME) and congenital deafness (CD), one had isolated congenital deafness (ICD), and one was healthy.
Methods and Results :  Molecular diagnosis performed by Southern blotting confirmed Unverricht-Lundborg disease in the available sibling with PME/CD. In the sibling with ICD (heterozygote for expansion mutation in CSTB ) we demonstrated recombination event between the D21S2040 marker and the CSTB gene and identified c.207delC (p.T70Xfs) mutation in the fourth exon of the transmembrane protease, serine-3 (TMPRSS3) gene (maps in close proximity to CSTB), responsible for nonsyndromic deafness in the sibling with PME/CD as well.
Discussion :  To the best of our knowledge this is the first genetic confirmation of the coexistence of these two mutations.     

A Large Sellar Granular Cell Tumor in a 21-year-old Woman

We report here the case of a 21-year-old woman with a large sellar tumor, extending to the suprasellar area associated with growth hormone deficiency, hypogonadism, hypocorticism, and hyperprolactinemia. Transsphenoidal surgery was performed, and histologic, immunohistochemical, and electron microscopic study lead to the diagnosis of granular cell tumor. These tumors are, in most cases, very small and are found incidentally at autopsy of older patients. Our case is exceptional because the tumor developed in a young woman, extended to the suprasellar region, and caused clinical symptoms.     

Synthetic oxygen carriers in cardiac tissue engineering

The prominence of cardiovascular diseases has prompted investigations into alternative treatment options, including tissue engineering. Currently, the biggest limitation in cardiac tissue engineering lies in delivering oxygen to all cells within the construct. Synthetic oxygen carriers hold much promise in that they have high affinity for oxygen and can be supplemented to culture medium without adverse effect on the cells. This review highlights two complementary studies by our group that utilized oxygen carriers in cardiac tissue engineering. Experimental and modeling studies were performed to evaluate the effect of a perfluorocarbon (PFC)-based synthetic oxygen carrier, Oxygent, on oxygen supply within tissue engineered cardiac constructs. Porous biorubber scaffolds with an array of parallel channels mimicking the capillary network were seeded with cardiomyocytes and fibroblasts, and cultivated in medium supplemented with PFC. The presence of PFC enhanced the transport of oxygen, increased oxygen concentrations, and yielded constructs that displayed stronger cardiac-like phenotype.