Evaluating an In-House Cell-Based Assay for Detecting Antibodies Against Muscle-Specific Tyrosine Kinase in Myasthenia Gravis

Background and PurposeDetecting antibodies against muscle-specific tyrosine kinase (MuSK Abs) is essential for diagnosing myasthenia gravis (MG). We applied an in-house cell-based assay (CBA) to detect MuSK Abs.MethodsA stable cell line was generated using a lentiviral vector, which allowed the expression of MuSK tagged with green fluorescent protein in human embryonic kidney 293 (HEK293) cells. Serum and anti-human IgG antibody conjugated with red fluorescence were added. The presence of MuSK Abs was determined based on the fluorescence intensity and their colocalization in fluorescence microscopy. Totals of 218 serum samples collected from 177 patients with MG, 31 with other neuromuscular diseases, and 10 healthy controls were analyzed. The CBA results were compared with those of a radioimmunoprecipitation assay (RIPA) and an enzyme-linked immunosorbent assay (ELISA).ResultsThe MuSK-HEK293 cell line stably expressed MuSK protein. The CBA detected MuSK Abs in 34 (19.2%) of 177 samples obtained from patients with MG and in none of the participants having other neuromuscular diseases or in the healthy controls. The clinical characteristics of the patients with MuSK MG determined based on the CBA were strongly correlated with known clinical features of MuSK MG. There was an almost perfect agreement between the results of the CBA and those of the RIPA (Cohen''s kappa=0.880, p<0.001) and ELISA (Cohen''s kappa=0.982, p<0.001).ConclusionsThe results of the in-house CBA showed excellent agreement with both the RIPA and ELISA. Our in-house CBA can be considered a reliable method for detecting MuSK Abs.     

Hair counts from scalp biopsy specimens in Asians.

BACKGROUND: Differences in hair density have been described according to the ethnic background in whites and blacks. Asians are known to have fewer hairs than whites. OBJECTIVE: We performed this study to assess the normal values of hair counts in scalp biopsy specimens from Koreans. METHODS: A total of 35 subjects with clinically normal occipital scalps (13 patients with androgenetic alopecia, 20 with patchy alopecia areata, and 2 healthy volunteers) were included. Horizontal sections of 4-mm punch biopsy specimens from clinically normal occipital scalps were examined at various levels from the papillary dermis to the subcutis, and follicular counts of terminal/vellus hairs and anagen/telogen hairs were obtained. RESULTS: The numbers of total hairs, terminal and vellus hairs, and terminal anagen hairs were significantly lower (P <.05) in Koreans compared with the published data of whites and blacks. Percent ratio of terminal anagen and telogen hairs were similar to whites and blacks. Follicular density was significantly lower (P <.05) in Koreans than in whites and blacks. In Koreans, female subjects had a significantly higher number of terminal hairs than male subjects (P <.05). CONCLUSION: Hair density is significantly lower in Koreans than in whites or blacks. Slight sexual difference exists in follicular counts in Koreans. Our data could be used as a guideline for determining normalcy in interpreting horizontal sections of scalp biopsy specimens from Asians.     

Gender-related difference in left ventricular diastolic elastance during exercise in patients with diabetes mellitus

Background Because the ratio of mitral inflow and annular velocity to stroke volume has been reported as an index of diastolic elastance (Ed), the hypothesis tested in the present study was that Ed during exercise would be more abnormal in female than in male patients with type 2 diabetes. Methods and Results Ed was measured at rest and during graded supine bicycle exercise (25W, 3-min increments) in 53 patients (27 males, mean age 53+/-14 years) with type 2 diabetes and 53 age- and gender-matched controls. The patients with diabetes were divided into 2 groups by gender. Ed was not significantly different at rest between men and women, but was significantly higher during exercise in women than in men (25 W, 0.15+/-0.04 vs 0.20+/-0.07, p=0.009; 50 W, 0.16+/-0.05 vs 0.21+/-0.08, p=0.0175). Conclusion Left ventricular (LV) diastolic elastance is abnormal during exercise, but not at rest, in patients with diabetes without overt heart disease. Female gender was associated with increased LV stiffness during exercise among patients with type 2 diabetes. (Circ J 2008; 72: 1443 - 1448).     

Plasticity and memory in the prefrontal cortex

Neuropsychological and neuroimaging studies in humans have shown that the prefrontal cortex (PFC) is involved in long-term memory functioning. In general, the participation of the PFC in long-term memory has been attributed to its role in executive control rather than information storage. Accumulating data from recent animal studies, however, suggest the possible role of the PFC in the storage of long-term memory. In support of this view, there is evidence that various projection systems in the PFC support long-term synaptic plasticity. Recording studies have further demonstrated neural correlates of learning in various animal species. Lastly, behavioral and physiological studies indicate that the PFC is critically involved in memory consolidation, retrieval and extinction processes. These studies then suggest that the PFC is an integral part of the neural network where long-term memory trace is stored and retrieved. Though decisive evidence is still lacking at present, we propose here to assign a term 'control memory' (i.e., memory for top-down control processes) as a new type of memory function for the PFC. This new principle of PFC-long-term memory can help organize existing data and provide novel insights into future empirical studies.     

Effect of bilateral subthalamic deep brain stimulation on diphasic dyskinesia

OBJECTIVES: The goal of this study was to assess the effect of bilateral subthalamic deep brain stimulation (STN DBS) on levodopa-induced diphasic dyskinesia in patients with Parkinson disease (PD). PATIENTS AND METHODS: Six PD patients with diphasic dyskinesia were included in this study. Prior to surgery, the duration and severity of dyskinesia were determined in each patient, along with the Unified Parkinson Disease Rating Scale score and Hoehn and Yahr stage. Bilateral STN electrode implantation was performed during a single operation. RESULTS: The median duration of the follow-up period was 21.5 months (range 14-24 months). STN DBS had a beneficial effect on diphasic dyskinesia in all patients. At the last follow-up, 3 patients had no dyskinesia and 1 had only a small amount of peak-dose dyskinesia. One patient showed a reduction in the duration of diphasic dyskinesia, despite a lack of reduction in the total duration of dyskinesia. In the last patient, although the total duration of dyskinesia increased, the pattern of dyskinesia changed from severe painful disabling dyskinesia to the less severe peak-dose type of dyskinesia. There were no intraoperative or postoperative surgical complications. CONCLUSIONS: Bilateral STN DBS is good at reducing diphasic dyskinesia, and it can be a good therapeutic option for patients with diphasic dyskinesia.     

Herbal medicine Gamgungtang down-regulates autoimmunity through induction of TH2 cytokine production by lymphocytes in experimental thyroiditis model

The crude herbal formulation, Gamgungtang (GGT), has been shown to protect animals against a wide range of spontaneously developing or induced autoimmune diseases. We have previously reported that GGT shows marked down-regulation of several experimental autoimmune diseases. Although very effective at preventing thyroid infiltrates in mice immunized with mouse deglycosylated thyroglobulin and complete Freund's adjuvant and in spontaneous models of thyroiditis, it completely failed to modify experimental autoimmune thyroiditis (EAT) induced in mice immunized with mouse thyroglobulin and lipopolysaccharide. In this study, in an effort to elucidate the mechanisms by which GGT suppresses EAT, and autoimmunity in general, we investigated the in vivo effects of this drug on the Th1/Th2 lymphocyte balance, which is important for the induction or inhibition of autoreactivity. Naive SJL/J mice were treated orally for 5 days with GGT (80 mg/(kg day)). Spleen cells were obtained at various time points during the treatment period and were stimulated in vitro with concanavalin A. Interleukins IL-4, IL-10 and IL-12, transforming growth factor-beta (TGF-beta) and interferon-gamma (IFN-gamma) cytokine production was evaluated at the protein levels of the cytokines in the medium and mRNA expressions. A significant upregulation of IL-4, IL-10 and TGF-beta was observed following treatment with GGT, which peaked at day 5 (IL-10) or day 10 (IL-4). On the other hand, IL-12 and IFN-gamma production were either unchanged or decreased. It seems therefore that GGT induces in vivo a shift towards Th2 lymphocytes which may be one of the mechanisms of down-regulation of the autoimmune reactivity in EAT. Our observations indicate that down-regulation of TH1 cytokines (especially IL-12) and enhancement of Th2 cytokine production may play an important role in the control of T-cell-mediated autoimmunity. These data may contribute to the design of new immunomodulating treatments for a group of autoimmune diseases.