The protective effects of beta-mangostin against sodium iodate-induced retinal ROS-mediated apoptosis through MEK/ERK and p53 signaling pathways

Previous studies have indicated that NaIO3 induces intracellular reactive oxygen species (ROS) production and has been used as a model for age-related macular degeneration (AMD) due to the selective retinal pigment epithelium (RPE) cell damage it induces. Beta-mangostin (BM) is a xanthone-type natural compound isolated from Cratoxylum arborescens. The influence of BM on NaIO3-induced oxidative stress damage in ARPE-19 cells has not yet been elucidated. In this study, we investigated how BM protects ARPE-19 cells from NaIO3-induced ROS-mediated apoptosis. Our results revealed that BM notably improved cell viability and prevented ARPE-19 cell mitochondrial dysfunction mediated-apoptosis induced by NaIO3; it was mediated by significantly reduced NaIO3-upregulated ROS, cellular H2O2 production and improved downregulated glutathione and catalase activities. Furthermore, we found that BM could suppress the expression of Bax, cleaved PARP, and cleaved caspase-3 by decreasing phosphorylation of MEK/ERK and p53 expression in NaIO3-induced ARPE-19 cells. At the same time, we also used MEK inhibitors (PD98059) to confirm the above phenomenon. Moreover, our animal experiments revealed that BM prevented NaIO3 from causing retinal deformation; it led to thicker outer and inner nuclear layers and downregulated cleaved caspase-3 expression compared to the group receiving NaIO3 only. Collectively, these results suggest that BM can protect the RPE and retina from NaIO3-induced apoptosis through ROS-mediated mitochondrial dysfunction involving the MEK/ERK and p53 signaling pathways.

Particulate matter 2.5 exposure induces epithelial-mesenchymal transition via PI3K/AKT/mTOR pathway in human retinal pigment epithelial ARPE-19 cells

Exposure to particulate matter 2.5 (PM2.5) has been linked to ocular surface diseases, yet knowledge of the molecular mechanism impacted on retina pathogenesis is limited. Therefore, the purpose of this study was to explore the effects and involved factors of PM2.5 exposure in human retinal pigment epithelial APRE-19 cells. Our data revealed a decreased cell viability and an increased migratory ability in APRE-19 cells after PM2.5 stimulation. The MMP-2 and MMP-9 protein levels were markedly increased while the MMPs regulators TIMP-1 and TIMP-2 were significantly reduced in PM2.5-exposed APRE-19 cells. PM2.5 also increased pro-MMP-2 expression in the cell culture supernatants. Additionally, PM2.5 promoted the EMT markers through the activation of PI3K/AKT/mTOR pathway. Moreover, the ICAM-1 production was also remarkably increased by PM2.5 but reduced by PI3K/AKT inhibitor LY294002 in APRE-19 cells. Taken together, these results suggest that PM2.5 promotes EMT in a PI3K/AKT/mTOR-dependent manner in the retinal pigment epithelium.

The Protective Effects of α-Mangostin Attenuate Sodium Iodate-Induced Cytotoxicity and Oxidative Injury via Mediating SIRT-3 Inactivation via the PI3K/AKT/PGC-1α Pathway

It is well known that age-related macular degeneration (AMD) is an irreversible neurodegenerative disease that can cause blindness in the elderly. Oxidative stress-induced retinal pigment epithelial (RPE) cell damage is a part of the pathogenesis of AMD. In this study, we evaluated the protective effect and mechanisms of alpha-mangostin (α-mangostin, α-MG) against NaIO₃-induced reactive oxygen species (ROS)-dependent toxicity, which activates apoptosis in vivo and in vitro. MTT assay and flow cytometry demonstrated that the pretreatment of ARPE-19 cells with α-MG (0, 3.75, 7.5, and 15 μM) significantly increased cell viability and reduced apoptosis from NaIO₃-induced oxidative stress in a concentration-dependent manner, which was achieved by the inhibition of Bax, cleaved PARP-1, cleaved caspase-3 protein expression, and enhancement of Bcl-2 protein. Furthermore, pre-incubation of ARPE-19 cells with α-MG markedly inhibited the intracellular ROS and extracellular H₂O₂ generation via blocking of the abnormal enzyme activities of superoxide dismutase (SOD), the downregulated levels of catalase (CAT), and the endogenous antioxidant, glutathione (GSH), which were regulated by decreasing PI3K-AKT-PGC-1α-STRT-3 signaling in ARPE-19 cells. In addition, our in vivo results indicated that α-MG improved retinal deformation and increased the thickness of both the outer nuclear layer and inner nuclear layer by inhibiting the expression of cleaved caspase-3 protein. Taken together, our results suggest that α-MG effectively protects human ARPE-19 cells from NaIO₃-induced oxidative damage via antiapoptotic and antioxidant effects.

High-voltage thin-film GaN LEDs fabricated on ceramic substrates: the alleviated droop effect at 670 W/cm(2)

High-voltage thin-film GaN LEDs with the emission wavelength of 455 nm were fabricated on ceramic substrates (230 W/m · K). The high-voltage operation was achieved by three cascaded sub-LEDs with dielectric passivation and metal bridges conformally deposited on the side walls. Under the driving power of 670 W/cm(2), the high-voltage LEDs exhibit much alleviated efficiency droop and the operative temperature below 80 °C. The excellent performances were attributed to the improved current spreading within each sub-LED and the superior heat sinking of the ceramic substrate.

Hemodynamic effects of the different vascular accesses used for double-filtration plasmapheresis

Systematic investigations of hemodynamic status during double filtration plasmapheresis (DFP) are rare in the literature. To investigate the hemodynamic effects of the vascular access chosen for DFP, variations in blood pressure (BP) and pulse rate (PR) induced acutely by DFP were prospectively analyzed in 46 myasthenia gravis (MG) patients a standard DFP protocol with isovolumetric saline fluid replacement. BP and PR were monitored at 30-min intervals (baseline, M30, M60, M90, and M120) during the procedures. The patients were randomized into central vein (CV) and peripheral vein (PV) groups based on the vascular access used. Systolic BP (SBP) dropped significantly at M60 (P < 0.05), M90 (P < 0.001), and M120 (P < 0.001) when compared to the baseline level. Symptomatic hypotension was not observed in any of the 46 sessions. SBP values during DFP in the CV group were significantly lower than the PV group's at M60 (93.1 vs. 101.0%, P < 0.05) and marginally lower at M90 (91.2 vs. 97.2%, P = 0.06). There was no significant difference in diastolic BP changes between the two groups. In the CV and PV groups, PR changes during plasmapheresis also differed at M90 (103.4 vs. 94.5%, P < 0.001) and M120 (101.3 vs. 95.0%, P < 0.05). The significantly lower SBP during DFP in the CV group at M60 may be due to the high central vein flow rate and resultant delay in volume replacement. In conclusion, the vascular access selected for DFP plays a role in the pathogenesis of plasmapheresis-related hypotension. Controlling flow rates may help to prevent hypotension.

Coagulation abnormalities in serial double-filtration plasmapheresis

Intensive plasma exchange can transiently alter the hemostatic system. However, the effect of serial double filtration plasmapheresis (DFP) on the hemostatic system has not been adequately described. In this study, we sought to characterize the hemostatic effects of DFP in 32 myasthenia gravis patients who received one course of DFP treatment for five consecutive sessions within 10 days. Platelet count, prothrombin time (PT), partial thromboplastin time (PTT), and serum levels of albumin, globulin, cholesterol, and fibrinogen were measured before and after the course of DFP. Patients were divided into mild hypofibrinogenemia (MH) and severe hypofibrinogenemia (SH) groups based on post-plasmapheresis residual levels of fibrinogen above or below 70 mg/dl. The baseline fibrinogen level was significantly lower in the SH group (P < 0.01). After five sessions of DFP, the fibrinogen level was reduced to below 70 mg/dl in 14 patients (44%). The percentage of excessive prolongation of PT or PTT was significantly higher in the SH group. The SH group also had higher reduction rates of globulin and cholesterol (P < 0.05). Oozing in the punctured site of the central venous catheter occurred in 6 out of 26 patients, with four cases in the MH group and two in the SH group. There was no difference in the overall incidence of bleeding complications between the two groups. Only one episode of clinically overt bleeding occurred during the study after a large-bore femoral catheter was removed soon after the patient had received five consecutive daily treatments. The bleeding stopped after transfusion of 6 units of fresh frozen plasma. In conclusion, despite the obvious reduction of fibrinogen level and the modest decrease in platelet count after an intensive course of DFP treatment, the low incidence of clinically overt bleeding confirmed the safety of DFP.

Removal of arsenic from groundwater using point-of-use reverse osmosis and distilling devices

Ground water in both the northeastern and southwestern coast areas of Taiwan may contain high concentrations of arsenic. Since no central water supply system is available in some of those areas, point-of-use (POU) water purification devices are considered as an option for providing safe drinking water. In this study, removal of arsenic, using two types of POU purification devices, reverse osmosis (RO) systems and distillers, was investigated. Three commercially available RO systems and two distillers were selected to test their removal efficiency of arsenic from synthetic and real ground water. Experimental results of the three RO systems using synthetic ground water showed that only one system had good removal efficiency for arsenic. In subsequent experiments using real ground water with 0.7 mg l(-1) arsenic, only one RO system was able to meet the drinking water standard after producing about 1,000 l of treated water. For the distilling systems, 99% of the arsenic was removed from both synthetic and real groundwater. The arsenic concentrations in the finished water of both distillers were all below the standard for drinking water. Although systems with higher arsenic removal efficiency seemed to have better removal of total dissolved solids (TDS), no correlation could be found after analysis.

Therapeutic apheresis in Taiwan

From July 1, 1999, to June 30, 2000, the Formosan Blood Purification Society conducted a survey on the current status of therapeutic apheresis (TA) treatments in Taiwan. There were 13 centers with a total of 437 patients, 498 courses, and 2,086 procedures. The most common indication was for neurological disorders (58.4%), which included mainly myasthenia gravis (34.9%) and Guillain-Barré syndrome (18.2%). The other indications were hematological disorders (19.3%), hepatic-pancreatic disorders (12.3%), and rheumatic disorders (7.1%). Seventy-one percent of TA treatments were reported to be effective. Plasma exchange (PE) performed by either centrifugation or the filtration method constituted 55.4% of TA treatments, the double-filtration (DF) method constituted 39.3% of treatments, and cytapheresis constituted 5.3% of treatments. The most common machines used for TA were the Plasauto iQ, the KM 8800, the Hemonetics series, and the Fenwal CS-3000. The overall frequency of complications was 42.2% per course and 12.9% per procedure. Among them, fever, urticaria, and hypotension were the major complications. As compared with the trends of TA treatment in the world, PE still represents the major TA treatment in Taiwan, which should be replaced by DF or more selective adsorptive methods to reduce the PE-related adverse effects.

Acute oxalate nephropathy induced by star fruit in rats

In this study, we intend to establish a connection between star fruit and acute oxalate nephropathy and also investigate predisposing factors for its development. Male Sprague-Dawley rats of 180 to 200 g were assigned to four groups; namely, control, experimental, fasting, and water-deprivation groups. The former two groups were subjected to both fasting and water deprivation, whereas the latter two groups were subjected to either fasting or water deprivation, respectively. Except for tap water for controls, the remaining groups were administered 4 mL/100 g of body weight of sour star fruit juice with an oxalate concentration of 2.46 g/dL. After these procedures, serial measurement of serum creatinine levels and kidney pathological examination were performed. Peak serum creatinine levels in the control, experimental, fasting, and water-deprivation groups were 0.50 +/- 0.04, 1.46 +/- 0.26, 0.68 +/- 0.20, and 0.52 +/- 0.08 mg/dL, respectively. The experimental group had a greater peak serum creatinine level (P < 0.05). Mean serum creatinine levels of the experimental group days 0, 1, 2, 3, 4, and 5 were 0.43 +/- 0.03, 1.11 +/- 0.18, 1.31 +/- 0.27, 1.16 +/- 0.28, 0.8 +/- 0.26, and 0.82 +/- 0.28 mg/dL, respectively. Mean serum creatinine levels days 1 to 3 were greater than that day 0 (P < 0.05). Pearson's correlation analysis of peak serum creatinine level and kidney weight for the experimental group showed a significant correlation (R = 0.75; P < 0.05; n = 9). In addition to typical changes of oxalate nephropathy, kidney pathological examination showed many refractile oxalate crystals with all rainbow colors under polarized light microscopy in the experimental group. In conclusion, sour star fruit with abundant oxalate contents could cause acute oxalate nephropathy in rats under the conditions of fasting and water deprivation.

Double filtration plasmapheresis in the treatment of myasthenic crisis--analysis of prognostic factors and efficacy

OBJECTIVES

To examine the prognostic factors and outcome of myasthenia gravis (MG) patients in crisis with double filtration plasmapheresis (DFP) treatment.

MATERIAL AND METHODS

A total of 15 patients experienced 20 episodes of crisis during the study period. Plasmapheresis was carried out using a double filtration

METHOD

Demographic information, clinical features of crisis, and associated complications were analyzed.

RESULTS

The median duration of crisis was 9 days. Chest infection was the most common precipitant of crisis. Twelve out of the 20 episodes (60%) responded well to DFP and mechanical ventilation was discontinued after the third session of DFP in 8 of them. Three significant predictors for prolonged crisis were shorter intervals between the onset of MG and the first crisis (P=0.04), higher serum bicarbonate levels at baseline (P=0.03) and the thymic pathology of thymoma (P=0.03).

CONCLUSION

DFP can ameliorate the profound weakness in crisis and seems to be a rational therapy for patients with myasthenic crisis.

Plasmapheresis in the treatment of ataxic sensory neuropathy associated with Sjögren's syndrome

Sjögren's syndrome (SS) is an important but poorly recognized cause of peripheral neuropathy. Several forms of peripheral nerve dysfunction occur, including trigeminal sensory neuropathy, mononeuropathy multiplex, distal sensorimotor polyneuropathy and pure sensory neuronopathy. The pathological findings vary and the definite treatment is not known. Here we present 4 cases of acute ataxic sensory polyneuropathy with SS, and the experience of treatment with plasmapheresis (PP). The 4 patients were all females; ages ranged from 30 to 58 years. All had prominent loss of kinesthetic and proprioceptive sensation. The course ranged from acute to subacute onset. Patients were treated with 5-9 sessions of PP. Two patients with initiation of treatment within 2 weeks of onset showed dramatic and sustained responses after PP, while the other 2 had no detectable effects. Our experience showed that PP should be considered in patients who present with sensory neuropathy associated with SS, and the treatment should be given as early as possible.

Novel CD28-responsive enhancer activated by CREB/ATF and AP-1 families in the human interleukin-2 receptor alpha-chain locus

The interaction of interleukin-2 (IL-2) with its receptor (IL-2R) critically regulates the T-cell immune response, and the alpha chain CD25/IL-2Ralpha is required for the formation of the high-affinity receptor. Tissue-specific, inducible expression of the IL-2Ralpha gene is regulated by at least three positive regulatory regions (PRRI, PRRII, and PRRIII), but none responded to CD28 engagement in gene reporter assays although CD28 costimulation strongly amplifies IL-2Ralpha gene transcription. By DNase I hypersensitivity analysis, we have identified a novel TCR-CD3- and CD28-responsive enhancer (CD28rE) located 8.5 kb 5' of the IL-2Ralpha gene. PRRIV/CD28rE contains a functional CRE/TRE element required for CD28 signaling. The T-cell-specific, CD28-responsive expression of the IL-2Ralpha gene appears controlled through PRRIV/CD28rE by cooperation of CREB/ATF and AP-1 family transcription factors.

Plasmapheresis-related hypotension

Hypotension is an uncommon complication of procedures involving extracorporeal circulation, including plasmapheresis. From November 1993 to March 1999, we treated 139 patients who underwent a total of 1,137 sessions of double filtration plasmapheresis (DFP). Hypotension was defined as a systolic blood pressure (BP) < 80 mm Hg or any decrease of systolic BP with systemic reactions. A total of 17 (1.5%) episodes of hypotension were documented in 15 patients during the study period. Hypotensive episodes occurred in 2.3% of patients with inflammatory neuropathy, 1.2% of patients with myasthenia gravis, and 1.2% of patients with all other medical diseases. Involvement of the autonomic nerve system (ANS) and a low baseline BP were associated with the occurrence of hypotension. Eight (47%) of 17 episodes were symptomatic and 2 were complicated with seizure. Patients with symptomatic hypotension had a higher level of systolic BP prior to DFP and a larger drop of systolic BP and pulse rate during hypotensive attacks compared to asymptomatic patients. Most hypotensive episodes were resolved briefly after intravenous infusion of saline within 30 min. Eight (47%) of the hypotensive episodes occurred during the first session of DFP treatment. Twelve (71%) of 17 episodes occurred during the last half period of treatment; 6 of them were noted during the terminating stage of DFP. In conclusion, in this series plasmapheresis-related hypotension occurred in 1.5% of DFP sessions and had a higher prevalence in patients with ANS instability and low BP. Extra caution in monitoring BP during DFP therapy is warranted in these vulnerable patients, especially during the termination phase of the first DFP session.

The six year experience of plasmapheresis in patients with myasthenia gravis

Plasmapheresis (PP) effectively removes autoantibodies in various autoimmune diseases. The use of PP in the treatment of myasthenia gravis (MG) has been widely accepted since the 1970s. The treatment protocol, however, has not been standardized. For the last 6 years, we collected a total of 94 MG patients, 38 males and 56 females aged 14-80 years, who received 175 courses of PP treatment for a total of 823 sessions. The methods we used were double filtration plasmapheresis (DF), immunoadsorption plasmapheresis (IA), and plasma exchange (PE). There were 167 courses of DF, 6 courses of IA, and 2 courses of PE. Each course of treatment consists of 4 to 5 sessions of apheresis. The processed volume of plasma is 1 calculated plasma volume. All patients tolerated PP well although 2.3% of them experienced hypotension. Our experiences are summarized as follows. Both DF and IA effectively ameliorate symptoms and signs of MG. IA removes acetylcholine receptor antibody more effectively than DF does, but clinical effects between these 2 methods are similar. A daily schedule seems more effective than an alternate daily schedule. The optimal number of PP sessions for each course is 4. The factors correlating with better clinical response are high MG score, nonthymoma patients, younger age at onset, and higher removal rate for immunoglobulin G.

Comparison between double-filtration plasmapheresis and immunoadsorption plasmapheresis in the treatment of patients with myasthenia gravis

Two techniques for plasmapheresis are used in the treatment of myasthenia gravis (MG): immunoadsorption (IA) and double filtration (DF). This controlled study evaluated the differences between these techniques in clinical effects and serological changes. Five patients with generalized MG (clinical states IIb and III) were enrolled; each patient received IA and DF plasmapheresis on separate occasions. Immunosorba TR-350 with an affinity to acetylcholine receptor antibodies (AchRAb) was used for IA, while Evaflux 4A was used as the plasma fractionator for DF. Each course of treatment consisted of five sessions of apheresis. MG score, titers of AchRAb, immunoglobulins (Ig), and plasma biochemistry were assessed by blinded examiners before and immediately after the entire course of treatment. Both treatments effectively ameliorated symptoms of MG. There were no significant changes in MG score between the two groups (IA vs. DF: 2.2 vs. 2.6, P> 0.5). IA had a higher clearance rate of AchRAb than DF (66 % vs. 54 %, P< 0.05), while DF removed more IgA (72% vs. 21%, P< 0.05) and IgM (89% vs. 57%, P< 0.01) than did IA. Although IA removed AchRAb more effectively than DF, the clinical effects between these two treatments were similar. The titers of AchRAb cannot reflect the clinical severity. Some circulating factors other than AchRAb may contribute to the pathogenesis of MG.

Optimal volume of processed plasma and total number of selective plasmapheresis sessions in the treatment of patients with severe generalized myasthenia gravis

The selection of the technical parameters of plasmapheresis in the treatment of patients with MG varies widely due to the lack of sufficient data from controlled studies to standardize the plasmapheresis procedure. Eight myasthenia gravis (MG) patients (Osserman IIb and III) received either immunoadsorption plasmapheresis (IA) with a IM-TR 350 (Asahi Medical Co., Tokyo, Japan) or double filtration plasmapheresis (DF) with a Cascadeflo AC-1770, with four in each group. A Plasmaflo AP 05 W (Asahi Medical Co., Tokyo, Japan) was used as the plasma separator in both groups. Each course of treatment consisted of five sessions of aphereses on alternate days. Plasma was sampled before and after passing through the column. Samples of plasma were analyzed for acetylcholine receptor antibody (AchRAb) at the start of plasmapheresis and sequentially after every 0.5 L of plasma treated. The IA method cleared significantly more AchRAb during the initial treatment of 1. 5 L of plasma than the DF method, especially in the initial 1 L (P < 0.01). The column saturated after treatment of 1.5 to 2 L of plasma. It is known that over-saturation of column may release the already adsorbed/filtrated antibodies. Longitudinal analysis on the serological changes during the five sessions revealed that the clearance obtained using the IA method was significantly higher and more sustained after the first session of treatment compared to the DF method (P < 0.05). The titers of AchRAb were also noted to rise after the fourth session. These results suggest that 2 L of processed volume is optimal in terms of the functional capacity of a plasmapheresis column in either IA or DF methods, and that a total of four sessions of treatment in one course may provide optimal elimination of AchRAb.

Experience of double filtration plasmapheresis in the treatment of Guillain-Barré syndrome

Therapeutic plasma exchange (TPE) is a standard treatment in Guillain-Barré syndrome. TPE may require exogenous fluid for replacement of plasma and, depending on the equipment used, varying extracorporeal volumes. Potential adverse effects include allergic reaction, infection, and hypotension. From September 1993 to December 1997, we treated 16 patients with Guillain-Barré syndrome by a newly developed method of automated double filtration plasmapheresis (DFPP). Patients (ten males and six females, age ranged from 16 to 73) suffering from acute ascending motor weakness and fulfilling the diagnostic criteria for GBS were chosen for DFPP. Each patient received at least five sessions of apheresis in 7 to 10 days and approximately 2.5 to 3.0 L of plasma was treated in each session. Patients were evaluated by disability grade according to a Hughes scale. The mean grade of disability was 3.62 at treatment and improved to 2.37 four weeks after the start of DFPP. The median time to grade 2 (walk without support) was 19 days. There were five patients (41.6%) in need of respirator support. The median time to weaning off the respirator was 9 days. Only two patients (12.5%) could not reach grade 2 at the end of 6 months. Our results were comparable to previously published results of TPE. We conclude that DFPP may be as effective as TPE in the treatment of GBS.

Double filtration plasmapheresis in myasthenia gravis--analysis of clinical efficacy and prognostic parameters

OBJECTIVES

The aim of this study was to evaluate the efficacy of double filtration plasmapheresis (DFP) in the treatment of patients with myasthenia gravis (MG) and to analyze the possible prognostic factors related to responsiveness to DFP.

MATERIALS AND METHODS

We treated 45 MG patients, 26 women and 19 men aged 21-72 years, with DFP for 5 consecutive sessions. All were affected by severe generalized or respiratory weakness with an Osserman's classification of group 2 or 3 and had not responded to previous treatments.

RESULTS

Thirty-eight out of 45 patients (84%) achieved significant improvements after DFP. The baseline MG score and removal rate for immunoglobulin G (IgG) were significantly higher in the patients with good response than in the other response groups. Poor responders were more likely to have thymoma and a longer interval among sessions of DFP. Better response in patients with age at onset of less than 40 years was associated with higher MG score. Serum concentration of all proteins tested fell as follows (mean +/- SD): IgM, 88+/-7%; IgA, 71+/-11%; IgG, 59+/-14%; globulin, 52+/-11%; AchRAb, 47+/-14%; and albumin, 27+/-10%. All the patients tolerated plasmapheresis well except for 2.2% who experienced hypotension.

CONCLUSION

In this study, DFP was effective and safe in the treatment of patients with severe generalized MG. The factors correlating with the better clinical response were high MG score, a thymic pathology of non-thymoma, daily apheresis, young age at onset, and high removal rate for IgG.

Sequential plasmapheresis and intravenous immunoglobulin therapy for refractory myasthenia gravis: case report

Immunotherapy is currently the standard therapy for myasthenia gravis (MG) although some patients may be refractory to treatment. We describe the use of sequential plasmapheresis and intravenous immunoglobulin (IVIG) therapy for treatment of advanced MG in a patient refractory to all forms of medical treatment including corticosteroids, immunosuppressants, and intermittent plasmapheresis. The patient, a 37-year-old woman with systemic lupus erythematosus (SLE), had initially responded well to treatment with high dose corticosteroids and intermittent plasmapheresis, with the duration of response ranging from 3 to 4 months. However, after 18 months of therapy, the duration of response had gradually decreased to 1 month. She responded well to a 5 day trial of plasmapheresis followed by high dose IVIG, and the duration of response increased to 6 months. The SLE activity was relatively silent during each relapse. This report indicates the potential usefulness of sequential plasmapheresis and IVIG in the treatment of patients with refractory MG and SLE.

[Immunoadsorption therapy for myasthenia gravis: study on the adsorption capacity of an immunoadsorption column]

Circulating antibodies to the acetylcholine receptor (AchRAb) are detectable in most of the patients with generalized myasthenia gravis (MG). Plasmapheresis has been shown to induce a rapid recovery in company with the decline of the AchRAb titers. Immunoadsorption plasmapheresis (IP) was performed in five patients (three men and two women, mean age 49.6 years) with advanced MG who were refractory to thymectomy and immunosuppressants. Plasmaflo AP 05W was used as a plasma separator and Immusorba TR-350 was used as an immunoadsorption column for plasma perfusion. Each course of treatment consisted of 5 sessions of plasmapheresis on alternate days. Plasma was sampled before and after passage through the adsorption column. We analyzed AchRAb titer in the samples of zero time and sequentially at every 0.5 L of plasma treated. The mean titer of AchRAb in the plasma before passing the adsorption column decreased gradually after every 0.5 L perfused plasma up to 2 L. After perfusion of 2 L plasma, the titer of AchRAb rebounded partly. The mean reduction rate of AchRAb at initial 1 L perfusion of plasma was approximately 100% among sessions of treatment. When the perfusion volume was over 2 L, nearly 50% of AchRAb had not adsorbed through the adsorption column among sessions. The mean titer of AchRAb fell to 74.6%, 52.6%, 43.3%, 35.8%, and 36.5% of the original level after each session of IP. In conclusion, a total of 4 sessions of IP with perfusion of 2 L plasma is an ideal treatment of patients with MG in terms of functional capacity of an immunoadsorption column.

Dominant-inherited hypokalemic periodic paralysis in a large Chinese family

Familial hypokalemic periodic paralysis (HoPP) is a rare condition among Chinese. We studied a large Chinese family (48 members in six generations) with dominant-inherited HoPP, using incidental tracing of family history of a proband who presented with the typical features of HoPP. Fifteen family members were found to have the disease. We found the familial type of HoPP to differ from the sporadic type in Taiwan, in that the familial type has an equal gender distribution, earlier onset of paralytic attacks, and more severe clinical features in both frequency and extent. When these patients were compared with Caucasian families, the common features were the involvement of the respiratory and the bulbar muscles, and the eye muscles in Chinese patients. Cold-induced attacks and permanent muscle weakness were not common in Chinese subjects. Age and history of paralytic attacks were not the major determinants for the development of permanent muscle weakness. Two family members died during attacks because of severe involvement of the respiratory and bulbar muscles.

Plasmapheresis in myasthenia gravis. A comparative study of daily versus alternately daily schedule

OBJECTIVES

The aim of this study was to compare the efficacy of different protocols of plasmapheresis in the treatment of myasthenia gravis (MG).

MATERIALS AND METHODS

We treated 30 MG patients with plasmapheresis on either a daily or alternately daily schedule for 5 consecutive sessions. Acetylcholine receptor antibody (AchRAb), serum proteins including albumin, globulin, immunoglobulin G (IgG), IgA, and IgM, and MG score were measured before and after the course of plasmapheresis in each group of patients.

RESULTS

The mean percent reductions of serum proteins including IgA (81.5% vs 69.7%), IgM (95.6% vs 87.1%), and globulin (63.2% vs 50.1%) were significantly higher in the daily group. There were no significant differences in AchRAb and IgG levels after treatment between these 2 groups. However, the reduction of MG score was greater in the daily group. All the patients tolerated plasmapheresis well except for 2.7% of them who experienced hypotension.

CONCLUSION

Our results suggest that daily plasmapheresis may be more effective in the treatment of patients with advanced MG.

Miller Fisher syndrome with central involvement: successful treatment with plasmapheresis

Miller Fisher syndrome is characterized by external ophthalmoplegia, ataxia, and areflexia. Most researchers favor a peripheral origin while others suggest a brainstem inflammatory lesion or a combination of central and peripheral demyelination. We report 2 cases of Miller Fisher syndrome with the typical triad of ataxia, areflexia, and ophthalmoplegia. Strong clinical evidence of central involvement included initial drowsiness, bilateral Babinski sign, and quadriparesis. Evoked potential studies showed prolongation of central conduction time. Plasmapheresis was performed to relieve respiratory failure in Patient 1 and to shorten the duration of nasogastric tube feeding due to severe bulbar palsy in Patient 2. Significant improvement of electrophysiologic parameters was recorded after plasmapheresis. Abnormal evoked potentials, together with clinical evidence of central nervous system abnormalities, support the hypothesis that there is a combination of peripheral and central involvement in Miller Fisher syndrome in our patients. Plasmapheresis is highly effective in relieving the profound neurological deficits of this atypical syndrome.

Mitogen-activated protein kinase kinase antagonized fas-associated death domain protein-mediated apoptosis by induced FLICE-inhibitory protein expression

Fas and Fas-associated death domain (FADD) play a critical role in the homeostasis of different cell types. The regulation of Fas and FADD-mediated cell death is pivotal to many physiological functions. The activation of T lymphocytes by concanavalin A (Con A) inhibited Fas-mediated cell death. We identified that among the several activation signals downstream of Con A stimulation, mitogen-activated protein (MAP) kinase kinase (MKK) was the major kinase pathway that antagonized Fas-triggered cell death. MKK1 suppressed FADD- but not caspase-3- induced apoptosis, indicating that antagonism occurred early along the Fas-initiated apoptotic cascade. We further demonstrated that activation of MKK1 led to expression of FLIP, a specific inhibitor of FADD. MKK1 inhibition of FADD-induced cell death was abrogated if induction of FLIP was prevented, indicating that FLIP mediates MKK1 suppression of FADD-mediated apoptosis. Our results illustrate a general mechanism by which activation of MAP kinase attenuates apoptotic signals initiated by death receptors in normal and transformed cells.

Double filtration plasmapheresis in the treatment of inflammatory polyneuropathy

Twelve cases of recognized inflammatory polyneuropathy were treated by plasmapheresis (PP) at Shin-Kong Wu Ho-Su Memorial Hospital from November 1993 to November 1995. These include 6 cases of acute inflammatory demyelinating polyneuropathy (AIDP), 4 cases of chronic inflammatory demyelinating polyneuropathy (CIDP), one case of Fisher syndrome, and one case of Sjögren's syndrome with polyneuropathy. The patients chosen for PP met the inclusion criteria of severely disabled, i.e., Grade 4 (bed or chair bound) or Grade 5 (required assisted ventilation), or an unremittingly progressive course. Plasmapheresis was carried out by the double filtration method. Each patient received a standard course of at least 4 sessions of pheresis. All the patients receiving PP showed a beneficial response. The treatment for 10 patients was judged to be effective. The other 2 patients (one AIDP and one CIDP), though improved, were unable to reach Grade 2. Among the complications of PP, only 4 episodes of symptomatic hypotension were noted in a total of 73 sessions of PP. In conclusion, PP is safe and effective in treating inflammatory polyneuropathy.

Hybrid free-space optical bus system for board-to-board interconnections

A free-space optical bus system is described for board-to-board interconnections at the backplane level. The system uses active optoelectronic modules as the interface between the circuit boards and the electrical backplane. Substrate-mode holograms are used to implement signal broadcast operations between boards, and each board on the backplane shares common free-space channels for transmitting and receiving signals. System-design considerations are given, and the potential performance of the optical bus system is evaluated. An experimental demonstration is also presented for the signal broadcast operation through cascaded substrate-mode holograms at a data rate of 622 Mb/s.

Free-space holographic optical interconnects for board-to-board and chip-to-chip interconnections

We describe a free-space holographic optical interconnect system designed for signal communication between chips and circuit boards on a common backplane. The system uses a transparent optical substrate-mode holograms to implement chip-to-chip interconnections and free space for board-to-board interconnections. Realization of a variety of interconnect functions with substrate-mode holograms is described. A three-board holographic interconnect system is also experimentally demonstrated.

Substrate-mode holograms used in optical interconnects: design issues

We discuss a number of design issues that affect the performance tolerances of substrate-mode holograms used for optical interconnect systems. We examine the effects of emulsion uniformity, thickness variation, and index variation on the ability to determine the Bragg angle and the diffraction angle within the substrate accurately. The environmental stability with respect to temperature, laser irradiance, and humidity are considered. Experimental results are presented for substrate-mode holograms fabricated in spin-coated dichromated-gelatin emulsions. The coupling properties for a 1 × 2 multiplexed substrate-mode hologram with two superimposed gratings are also described.

Combined electroneurographic and electromyographic studies in lead workers

OBJECTIVES

To evaluate the effects of chronic exposure to lead on the peripheral nervous system in lead workers.

METHODS

Nerve conduction velocity and electromyographic studies were performed on 31 lead workers of a battery recycling factory and 31 sex and age matched controls. 25 cases with mild distal extensor weakness of the upper limbs were classified as the lead neuropathy subgroup and the rest of the lead workers as the lead exposure subgroup. Blood lead concentrations and haematological and biochemical data were recorded. An index of cumulative exposure to lead was calculated by the summation of multiplying the average blood concentration of lead with the duration of exposure at various jobs.

RESULTS

Compared with the control group, the distal motor latency of the median nerve was significantly prolonged in the lead neuropathy subgroup, but not in the exposure subgroup. Only six of 31 workers had nerve conduction abnormalities, whereas electromyographic evidence of denervation was found in 93.5% of the lead neuropathy subgroup and 83.5% in the lead exposure subgroup. The electromyographic abnormalities found were neurogenic polyphasic waves in all 29 workers with abnormal electromyographic findings (grade in seven cases and grade ++ in the rest). Spontaneous activity was only recorded in seven workers, with grade + in four and grade ++ in three. There was a positive linear correlation between the index of cumulative exposure to lead and the distal motor latencies of the tibial nerve as well as a negative correlation with conduction velocities of the sural nerve after multivariate analysis and control of potential confounding by age and sex. No correlation could be found between the electrophysiological values and a simple duration of exposure or concentration of blood lead. A non-parametric analysis showed that there was a trend of higher index of cumulative exposure to lead with more severe electromyographic changes. Electromyographic abnormality also occurred in workers with blood lead concentrations between 17.4 and 58 micrograms/dl.

CONCLUSION

Electromyographic study in the distal extensors of the upper limbs may be used as a tool for biological monitoring of effect in lead workers.

Distributed optical data bus for board-level interconnects

A design for a distributed free-space optical system is presented that provides interconnection of electronic processing elements at the board level of packaging. The system can be expanded to more than two boards and transfers an array of data in parallel between connection planes. The design uses binary optic microlens arrays to collimate and collect light from surface-emitting lasers, and it uses substratemode holographic window elements for directing light to and from the bus region. The use of a collection lens array for extending the alignment tolerance of the imaging system is also discussed. The paper concludes with experimental demonstrations of critical system components and performance with 64-bit data arrays.

Isolation of two bovine amelogenin peptides and their amino acid sequences

Two peptide fractions of bovine amelogenin having a highly aggregative property to form polymers were purified by chromatography, SDS-polyacrylamide gel electrophoresis, and HPLC. Amino acid sequences of purified peptides were determined by automated Edman degradation. One peptide was found to be composed of 63 amino acid residues having a molecular weight of 7105, and the other of 86 residues having that of 9683. The sequence of the smaller peptide was identical to the C-terminal 63 residues of the amelogenin molecule of 170 residues previously reported, but the larger contained eight residues which are absent in the amelogenin sequence. There is a possibility that the latter peptide might be synthesized independently from mRNA spliced at different positions.