Molecular and biophysical characterization of the glycinergic inhibitory system.

Glycinergic neurotransmission is a major inhibitory influence in the CNS and defects are associated with paroxysmal neuromotor disorder, hyperekplexia with mutations in subunits of the inhibitory glycine receptor which facilitates postsynaptic ligand-binding, ion-channels. This study investigates the human glycinergic system by; 1) Mutation analysis of glycinergic candidate genes in hyperekplexia: the DNA sequencing of GLRAl in 88 hyperekplexia patients revealed 30 sequence variants; 21 were inherited in recessive mode or part of compound heterozygosity, indicating that recessive hyperekplexia is more common than previously expected. Further screening of the glycine transporter-2 gene (SLC6A5) as a candidate gene, 12 SLC6A5 mutations were found in 7 human hyperekplexia cases inherited predominantly by compound heterozygosity. 2) Biophysical analysis and molecular modelling of GLRAl mutations: which demonstrated that subcellular localisation defects were the major mechanism underlying recessive mutations. Other mutants typically show alterations in the dose-response curve for glycine suggestive of disrupted signal transduction. This study reports the first hyperekplexia mutation associated with leaky current suggesting tonic channel opening as a new receptor mechanism and fully-supported by molecular modelling. 3) Molecular and immunoreactive analysis of gephyrin heterogeneity in human brain: gephyrin encodes a multifunctional cytoplasmic protein important for organizing glycine and GABAa receptors at the postsynaptic membrane. Gephyrin has many different transcript isoforms and the study describes the population / distribution of gephyrin isoforms in neuronal tissues using molecular and immunohistochemical techniques. The heterogeneity of gephyrin cassettes indicates that each cassette is temporally and spatially regulated with unique patterns of glycine receptors co-localisation and we hypothesise that different gephyrin isoforms exhibit differential binding specificity affecting protein-protein interactions. This thesis describes that hyperekplexia is definitively a glycinergic disorder with several mechanism of molecular pathogenicity. Moreover, the underlying complexity of proteins, such as gephyrin, reveals further challenges in interpretating the functional significance of the neuronal heterogeneity

Characteristics of Back Muscle Strength in Patients with Scheduled for Lumbar Fusion Surgery due to Symptomatic Lumbar Degenerative Diseases

Study DesignCross sectional study.PurposeTo evaluate characteristics of back muscle strength in patients scheduled for lumbar fusion surgery.Overview of LiteratureLittle is known regarding muscle strength in patients with symptomatic lumbar degenerative diseases who require fusion surgery.MethodsConsecutive 354 patients scheduled for posterior lumbar interbody fusion due to symptomatic degenerative diseases were approached for participation. 316 patients were enrolled. Before surgery, muscle strength was assessed by measuring maximal isometric extension strength at seven angular positions (0°, 12°, 24°, 36°, 48°, 60°, and 72°) and mean isometric strength was calculated. The Oswestry Disability Index (0-100) and visual analogue scale (0-100) for back pain were recorded. Muscle strength was compared according to gender, age (0.05). Isometric strengths showed significant, but weak, inverse correlations with age and Oswestry Disability Index (r<0.4, p<0.05).ConclusionsIn patients with symptomatic lumbar degenerative diseases, back muscle strength significantly decreased, particularly at lumbar extension positions, and in females and older patients

Effects of Infrared Radiation and Heat on Human Skin Aging in vivo

Sunlight damages human skin, resulting in a wrinkled appearance. Since natural sunlight is polychromatic, its ultimate effects on the human skin are the result of not only the action of each wavelength separately, but also interactions among the many wavelengths, including UV, visible light, and infrared (IR). In direct sunlight, the temperature of human skin rises to about 40°C following the conversion of absorbed IR into heat. So far, our knowledge of the effects of IR radiation or heat on skin aging is limited. Recent work demonstrates that IR and heat exposure each induces cutaneous angiogenesis and inflammatory cellular infiltration, disrupts the dermal extracellular matrix by inducing matrix metalloproteinases, and alters dermal structural proteins, thereby adding to premature skin aging. This review provides a summary of current research on the effects of IR radiation and heat on aging in human skin in vivo

A Critical Role for Glycine Transporters in Hyperexcitability Disorders

Defects in mammalian glycinergic neurotransmission result in a complex motor disorder characterized by neonatal hypertonia and an exaggerated startle reflex, known as hyperekplexia (OMIM 149400). This affects newborn children and is characterized by noise or touch-induced seizures that result in muscle stiffness and breath-holding episodes. Although rare, this disorder can have serious consequences, including brain damage and/or sudden infant death. The primary cause of hyperekplexia is missense and non-sense mutations in the glycine receptor (GlyR) α1 subunit gene (GLRA1) on chromosome 5q33.1, although we have also discovered rare mutations in the genes encoding the GlyR β subunit (GLRB) and the GlyR clustering proteins gephyrin (GPNH) and collybistin (ARHGEF9). Recent studies of the Na+/Cl−-dependent glycine transporters GlyT1 and GlyT2 using mouse knockout models and human genetics have revealed that mutations in GlyT2 are a second major cause of hyperekplexia, while the phenotype of the GlyT1 knockout mouse resembles a devastating neurological disorder known as glycine encephalopathy (OMIM 605899). These findings highlight the importance of these transporters in regulating the levels of synaptic glycine

Modulation of Skin Collagen Metabolism in Aged and Photoaged Human Skin In Vivo

To the best of our knowledge, no study has been conducted to date to directly compare the collagen metabolism of photoaged and naturally aged human skin. In this study, we compared collagen synthesis, matrix metalloproteinase-1 levels, and gelatinase activity of sun-exposed and sun-protected skin of both young and old subjects. Using northern blot analysis, immunohistochemical stain, and Western blot analysis, we demonstrated that the levels of procollagen type I mRNA and protein in photoaged and naturally aged human skin in vivo are significantly lower than those of young skin. Furthermore, we demonstrated, by northern blot analysis, that the procollagen α1(I) mRNA expression of photoaged skin is much greater than that of sun-protected skin in the same individual. In situ hybridization and immunohistochemical stain were used to show that the expression of type I procollagen mRNA and protein in the fibroblasts of photoaged skin is greater than for naturally aged skin. In addition, it was found, by Western blot analysis using protein extracted from the dermal tissues, that the level of procollagen type I protein in photoaged skin is lower than that of naturally aged skin. The level of matrix metalloproteinase-1 protein and the activity of matrix metalloproteinase-2 were higher in the dermis of photoaged skin than in naturally aged skin. Our results suggest that the natural aging process decreases collagen synthesis and increases the expression of matrix metalloproteinases, whereas photoaging results in an increase of collagen synthesis and greater matrix metalloproteinase expression in human skin in vivo. Thus, the balance between collagen synthesis and degradation leading to collagen deficiency is different in photoaged and naturally aged skin

Prostate Specific Membrane Antigen mRNA in Blood as a Potential Predictor of Biochemical Recurrence after Radical Prostatectomy

We investigated whether the detection of prostate specific membrane antigen (PSMA) in blood preoperatively has predictive value for biochemical recurrence (BCR) after radical prostatectomy in patients with prostate cancer. All 134 patients scheduled to receive radical prostatectomy for prostate cancer were prospectively enrolled. The authors used nested reverse transcriptase-polymerase chain reaction (RT-PCR) assay to detect PSMA mRNA-bearing cells in peripheral blood, and analyzed the ability of PSMA mRNA positivity to predict BCR after surgery. PSMA-mRNA was detected in 24 (17.9%) patients by RT-PCR. Over a median follow-up of 20 months (range, 3 to 46 months), BCR developed in 15 patients (11.2%) and median time to BCR was 7 months (range, 3 to 25 months). Kaplan-Meier analysis revealed a significant difference between those positive or negative for PSMA in terms of recurrence-free actuarial probability (log rank P=0.0039). Multivariate analysis showed that positivity for PSMA mRNA (HR: 3.697, 95% CI 1.285-10.634, P=0.015) and a biopsy Gleason score of ≥7 (HR: 4.500, 95% CI 1.419-14.274, P=0.011) were independent preoperative predictors of BCR. The presence of PSMA mRNA in peripheral blood can be used to predict BCR after radical prostatectomy

Frontal lobe epilepsy: Clinical characteristics, surgical outcomes and diagnostic modalities

SummaryObjectiveTo identify surgical prognostic factors and to characterize clinical features according to the location of the intracranial ictal onset zone of frontal lobe epilepsy (FLE) in order to assess the role of various diagnostic modalities, including concordances with presurgical evaluations.MethodsWe studied 71 FLE patients who underwent epilepsy surgery and whose outcomes were followed for more than 2 years. Diagnoses were established by standard presurgical evaluation.ResultsClinical manifestations could be categorized into six types: initial focal motor (9 patients), initial versive seizure (15), frontal lobe complex partial seizure (14), complex partial seizure mimicking temporal lobe epilepsy (18), initial tonic elevation of arms (11), and sudden secondary generalized tonic–clonic seizure (4). Thirty-seven patients became seizure-free after surgery. Five patients were deleted in the analysis because of incomplete resection of ictal onset zones. The positive predictive value of interictal EEG, ictal EEG, MRI, PET, and ictal SPECT, respectively were 62.5%, 56.4%, 73.9%, 63.2%, and 63.6%, and the negative predictive value were 46.0%, 44.4%, 53.5%, 44.7%, and 51.7%. No significant relationship was found between the diagnostic accuracy of these modalities and surgical outcome, with the exception of MRI (p=0.029). Significant concordance of two or more modalities was observed in patients who became seizure-free (p=0.011). We could not find any clinical characteristic related to surgical outcome besides seizure frequency. No definite relationship was found between the location of intracranial ictal onset zone and clinical semiology.ConclusionAlthough various diagnostic methods can be useful in the diagnosis of FLE, only MRI can predict surgical outcome. Concordance between presurgical evaluations indicates a better surgical outcome