FC 105LITHIUM PRESERVES PERITONEAL MEMBRANE INTEGRITY BY REDUCING MESOTHELIAL CELL ΑB-CRYSTALLIN

Background and Aims

Renal replacement therapy by peritoneal dialysis (PD) is limited in use and duration by progressive impairment of peritoneal membrane integrity and homeostasis. Preservation of peritoneal membrane integrity during chronic PD remains an urgent but long-unmet medical need. PD therapy failure results from peritoneal fibrosis and angiogenesis caused by hypertonic PD fluid (PDF)-induced mesothelial cytotoxicity. The incompletely defined pathophysiological mechanisms involved confound informed selection of therapeutic targets. Addition of cytoprotective agents to PDF have been shown to counteract pathophysiological mechanisms induced by current PDF. Lithium is a well described inhibitor of glycogen synthase kinase 3β and has recently been shown to also have nephroprotective effects in low doses. Here, we aim to characterize icodextrin-based, PDF-induced cellular injury with a combined omics approach and to investigate the effects of LiCl on the PD-induced observed molecular perturbations.

Method

To investigate mechanisms of acute cellular damage by PDF we chose an in vitro model of primary omental-derived peritoneal mesothelial cells with direct exposure to icodextrin-based PDF, followed by short-term or extended recovery for detection of short-term and long-term changes in transcriptome, proteome, and cell injury. 0, 2.5 or 10 mM LiCl were added to the PDF. In-vitro findings were validated in peritoneal biopsies (n=41) from pediatric PD and CDK5 patients or healthy controls and peritoneal effluents from adult and pediatric PD patients (n=27) or ascites samples (n=4) as control. For in-vivo experiments, healthy and uremic mice (C57/Bl6, female) were chronically exposed to PD-fluid without or with the addition of 5 mM LiCl via an implanted catheter. In-vivo overexpression of CRYAB was induced by i.p. injection of an adenoviral vector. All animal experiments and use of patient samples were approved by the local ethics committees and performed according to animal protection laws or the Declaration of Helsinki, respectively.

Results

LiCl significantly improved mesothelial cell survival in a dose-dependent manner. Combined transcriptomic and proteomic characterization of icodextrin-based PDF-induced mesothelial cell injury identified αB-crystallin as the mesothelial cell protein most significantly and consistently counter-regulated by LiCl. In-vitro and in-vivo overexpression of αB-crystallin triggered a fibrotic phenotype and PDF-like upregulation of vascular endothelial growth factor (VEGF), CD31-positive cells, and TGFβ-independent activation of TGFβ-regulated targets. In contrast, αB-crystallin knock-down decreased VEGF expression and early mesothelial-to-mesenchymal transition (MMT). LiCl reduced VEGF release and counteracted fibrosis- and angiogenesis-associated processes. αB-crystallin in patient-derived mesothelial cells was specifically upregulated in response to PDF and increased in peritoneal mesothelial cells from pediatric PD patient biopsies, correlating with markers of angiogenesis and fibrosis.

Conclusion

The cytoprotective effects of LiCl-supplemented PDF may be explained by counter-regulation of PD-induced angiogenesis via the novel target αB-crystallin. Reduction of mesothelial cell damage, peritoneal fibrosis and VEGF suggests therapeutic potential of this intervention. Repurposing LiCl as a cytoprotective PDF additive may offer a translatable therapeutic strategy to combat peritoneal membrane deterioration during PD therapy. Further study of LiCl-supplemented PDF is merited as a realistic approach to improving treatment longevity and patient outcomes during PD treatment.

IgG-anti-IgA antibodies: an autoimmune finding in patients with psoriasis vulgaris

AIM

Psoriasis is thought to be an autoimmune disease caused by inappropriate activation of the cellular immune system. In this study, we aimed to search out IgG-anti-IgA antibody levels, serum immunoglobulins and antinuclear antibodies (ANA).

METHODS

The study enrolled 38 psoriasis vulgaris patients and 40 healthy controls.

RESULTS

Mean IgG-anti-IgA levels were significantly higher in psoriasis patients. The frequency of positive ANA testing was 21.1%; however, there was no correlation between IgG-anti-IgA antibody levels and ANA positivity. Only one patient had low IgA levels without high IgG-anti-IgA concentrations.

CONCLUSION

The data about high IgG-anti-IgA antibody levels are noteworthy for a new evidence of autoimmune mechanism.

Quality of life and its relation with disease severity in Behçet's disease

OBJECTIVE

Since Behçet's disease (BD) is a systemic vasculitis, it may deteriorate the quality of life of the patients. We aimed to investigate the relationship between the disease severity and the quality of life in patients with BD.

METHODS

We studied 195 BD patients and 195 healthy controls who were matched with regard to age, gender and socio-economic status. Krause score was calculated to assess disease severity, while Short-form-36 (SF-36) and The World Health Organization Quality of Life (WHOQOL-100) were used to evaluate the quality of life in BD.

RESULTS

The overall SF-36 and WHOQOL-100 scale scores, as well as their domains were significantly lower in BD patients. In BD patients, "general health", "role-physical", domains of SF-36, and "psychological", "level of independence", "environment", "environmental-public" domains of WHOQOL-100 showed significantly negative linear correlations with Krause scores. In BD patients with arthritis, the scores of "general health", "physical functioning", "role emotional" domains of SF-36, and the scores of "psychological", "level of independence" and "social relations" domains of WHOQOL-100 were significantly worse than without arthritis. The scores of "pain" domain of SF-36 and "level of independence" domain of WHOQOL-100 were significantly worse in BD patients with vascular involvement, while the scores of "mental health" domain of SF-36 and "psychological" domain of WHOQOL-100 were significantly worse in BD patients with eye involvement.

CONCLUSION

Based on the evaluation of SF-36 and WHOQOL-100 scores, quality of life is impaired and related with disease severity in BD. Arthritis, eye involvement and vascular involvement seem to contribute to this impairment.

The frequency of nasal carriage in chronic urticaria patients

OBJECTIVE

Chronic urticaria is characterized by oedema of the skin and mucous membranes. Although many agents have been implicated, aetiology is unknown in 70 to 75% of patients. Infections and foci of chronic infections are most commonly held responsible for chronic urticaria. In this study, the frequency of nasal carriage as the occult focus of infection and sensitivity to antimicrobials are explored in patients with chronic urticaria.

MATERIAL AND METHOD

Ninety-four patients with chronic urticaria and 30 controls participated in the study, which was carried out at the Ege university medical faculty, department of dermatology between January 2004 and January 2005. Nasal swab specimens were taken from the patients and controls and incubated at 37 degrees C degrees for 48 h, and inoculated on standard bacterial medium (blood agar). Antimicrobial susceptibility of a growth from isolates of the nasal swab specimens was conducted. Data were analysed statistically using chi-square and Mann-Whitney U-tests.

RESULTS

Ninety-four patients with chronic urticaria (72.3% female and 27.7% male) and 30 controls (63.3% female and 36.7% male) comprised the study group. Mean age of the patients and controls were 42.6 and 33.8 years, respectively. Staphylococcus aureus was detected in swab specimens from the nasal cavity in 50 of the 94 patients (53.2%) with chronic urticaria and four of the 30 controls (13.3%). Testing revealed that the most susceptible antibiotics were cefaclor, ceftriaxone, amoxycillin-clavulanic acid, amikacin, netilmicin, and fucidic acid.

CONCLUSION

Growth on cultures prepared from nasal swab specimens of chronic urticaria patients was statistically higher than the control group. We detected resistance to growth against mupirocin, an antibiotic frequently used in nasal carriage. High nasal carriage of Staphylococcus aureus in patients with chronic urticaria compared to controls suggests that nasal carriage as a focus of infection should be kept in mind as aetiology.

Broad-band ultraviolet B phototherapy is associated with elevated serum thiobarbituric acid reactive substance and nitrite-nitrate levels in psoriatic patients

BACKGROUND

Although the local anti-inflammatory, immunosuppressive and oxidative activity of UVB is known, the systemic effect of UVB phototherapy in dermatological patients has not been investigated.

OBJECTIVE

We aimed to investigate the lipid peroxidation status (as represented by thiobarbituric acid reactive substance, TBARS) and nitrite-nitrate levels in psoriatic patients under broad-band ultraviolet B (BB-UVB) phototherapy in order to determine the systemic effects of UVB.

SUBJECTS AND METHODS

Thirty-two psoriatic patients and 20 healthy controls were included. Blood samples were obtained at the beginning, after 6-10 exposures to BB UVB phototherapy (mean 5 weeks) and at the end of the therapy period (mean 21 weeks). Serum TBARS and nitrite-nitrate levels were evaluated.

RESULTS

There was no statistically significant difference in serum TBARS and nitrite-nitrate levels between psoriatic patients (basal) and healthy volunteers. There was no statistically significant correlation between disease duration, disease severity, or the total cumulative dose of UVB and serum levels of TBARS and nitrite-nitrate in psoriatic patients. Total nitrite levels in samples obtained during and at the end of therapy were significantly higher than basal levels (P=0.033 and P=0.005, respectively). TBARS levels in samples obtained during and at the end of therapy were significantly higher than basal levels (P=0 and P=0.026, respectively). There was a negative correlation (r=-0.576, P=0.039) between the total nitrite and TBARS levels in psoriatic patients at the end of therapy.

CONCLUSION

Our study showed that chronic exposure to UV irradiation may lead to a systemic effect on lipid peroxidation and NO levels, which are shown by a significant elevation in TBARS and nitrite-nitrate levels in serum.

Erythromelanosis follicularis faciei et colli: report of involvement in two female patients

Erythromelanosis follicularis faciei is a rare disease characterized by reddish brown pigmentation and follicular papules localized on certain areas such as the face and neck. Young men are usually affected, but young women or children may be affected. Bilateral distribution is usual, but it may occur unilaterally. Histopathologically, hyperkeratosis, increased melanization and dilatation of the hair follicle are characteristic. Two female patients with typical localizations and clinical findings of the disease are reported here.

AE2 isoforms in rat kidney: immunohistochemical localization and regulation in response to chronic NH4Cl loading

Three splice variants of anion exchanger (AE)2 (AE2a, b, and c) have been described in the rat, but their relative distribution in rat kidney is not known. The purpose of this study was to describe the segmental and cellular distribution of the AE2 isoforms in the rat kidney and to evaluate whether the expression levels of these AE2 isoforms are regulated independently in response to chronic NH(4)Cl loading. Two polyclonal antibodies were generated, respectively, recognizing a NH(2)-terminal peptide unique to AE2a and an amino acid sequence common to AE2a and AE2b. Antibody specificities were tested using cells transfected separately with the AE2a, AE2b, and AE2c isoforms. Immunohistochemistry on sections of paraffin-embedded rat kidneys showed a distribution of AE2a/AE2b labeling in the kidney similar to the distribution of AE2 in the rat kidney reported previously. AE2 is highly expressed in the medullary thick ascending limb, cortical thick ascending limb (cTAL), and macula densa. The pattern of AE2a-specific labeling differed from the pattern of AE2a/AE2b labeling in that relatively more of the total immunolabel was observed in the terminal inner medullary collecting duct. NH(4)Cl loading (0.033 mmol NH(4)Cl/g body wt for 7 days) did not change the labeling of AE2 isoforms in the medulla, whereas the labeling in the cortex was intensified and included more distal parts of the cTAL. Immunoblotting confirmed upregulation of AE2a/b expression in the cortex. These results indicate that AE2a and AE2b are differentially expressed and regulated in the rat kidney. The regulation following NH(4)Cl loading of AE2b in the cTAL suggests a role for AE2 in transepithelial bicarbonate reabsorption in this segment.

Agonist-induced coordinated trafficking of functionally related transport proteins for water and ions in cholangiocytes

We previously proposed that ductal bile formation is regulated by secretin-responsive relocation of aquaporin 1 (AQP1), a water-selective channel protein, from an intracellular vesicular compartment to the apical membrane of cholangiocytes. In this study, we immunoisolated AQP1-containing vesicles from cholangiocytes prepared from rat liver; quantitative immunoblotting revealed enrichment in these vesicles of not only AQP1 but also cystic fibrosis transmembrane regulator (CFTR) and AE2, a Cl- channel and a Cl-/HCO3- exchanger, respectively. Dual labeled immunogold electron microscopy of cultured polarized mouse cholangiocytes showed significant colocalization of AQP1, CFTR, and AE2 in an intracellular vesicular compartment; exposure of cholangiocytes to dibutyryl-cAMP (100 microm) resulted in co-redistribution of all three proteins to the apical cholangiocyte plasma membrane. After administration of secretin to rats in vivo, bile flow increased, and AQP1, CFTR, and AE2 co-redistributed to the apical cholangiocyte membrane; both events were blocked by pharmacologic disassembly of microtubules. Based on these in vitro and in vivo observations utilizing independent and complementary approaches, we propose that cholangiocytes contain an organelle that sequesters functionally related proteins that can account for ion-driven water transport, that this organelle moves to the apical cholangiocyte membrane in response to secretory agonists, and that these events account for ductal bile secretion at a molecular level.

Periodontal lesions in lipoid proteinosis

Lipoid proteinosis is a rare autosomal recessive heritable disease. Clinical features are hoarseness starting in infancy and the formation of yellowish papules and plaques on the skin and mucous membranes of the nose, oral cavity, pharynx and larynx. Light and electron microscopy demonstrates a subepithelial accumulation of PAS-positive (hyaline) material around blood vessels and in the dermis. This case is unusual in that the gingiva is also involved in the lipoid proteinosis.

REF-1, a protein with two bHLH domains, alters the pattern of cell fusion in C. elegans by regulating Hox protein activity

Hox genes control the choice of cell fates along the anteroposterior (AP) body axis of many organisms. In C. elegans, two Hox genes, lin-39 and mab-5, control the cell fusion decision of the 12 ventrally located Pn.p cells. Specific Pn.p cells fuse with an epidermal syncytium, hyp7, in a sexually dimorphic pattern. In hermaphrodites, Pn.p cells in the mid-body region remain unfused whereas in males, Pn.p cells adopt an alternating pattern of syncytial and unfused fates. The complexity of these fusion patterns arises because the activities of these two Hox proteins are regulated in a sex-specific manner. MAB-5 activity is inhibited in hermaphrodite Pn.p cells and thus MAB-5 normally only affects the male Pn.p fusion pattern. Here we identify a gene, ref-1, that regulates the hermaphrodite Pn.p cell fusion pattern largely by regulating MAB-5 activity in these cells. Mutation of ref-1 also affects the fate of other epidermal cells in distinct AP body regions. ref-1 encodes a protein with two basic helix-loop-helix domains distantly related to those of the hairy/Enhancer of split family. ref-1, and another hairy homolog, lin-22, regulate similar cell fate decisions in different body regions along the C. elegans AP body axis.

Effects of using a photographic cueing package during routine school transitions with a child who has autism

Making successful transitions from one activity to another is difficult for many children, particularly those who have cognitive, language, or behavioral disabilities. Appropriately terminating one activity and initiating another in a timely fashion is a skill important for young children to learn prior to entering kindergarten. The efficacy of teaching a young child labeled as having autism to make successful transitions in daily routines in three different school settings through the use of photographic cue package was examined. A multiple baseline across-settings design was used to evaluate the efficacy of the intervention. Implications for the use of photographic cue packages in teaching a variety of activities to young children are discussed.

Interdependence and Controversy in Group Decision Making: Antecedents to Effective Self-Managing Teams

Self-managing teams have the challenge to make decisions regarding their tasks and to manage their internal affairs. Findings on 60 self-managing teams with 540 employees indicate that the theory of cooperation and competition is useful for identifying the social processes that help these teams grapple with problems and work effectively. Specifically, teams with highly cooperative goals were found to discuss their opposing views open-mindedly and constructively which in turn developed confidence in team dynamics that contributed to effective team performance. Competitive goals appeared to interfere with constructive controversy, confidence, and effectiveness. Findings were interpreted as suggesting that structuring cooperative goals and constructive controversy can help self-managing teams gain confidence and work productively. Copyright 1998 Academic Press.

Oral magnesium supplements reduce erythrocyte dehydration in patients with sickle cell disease

Intracellular polymerization and sickling depend markedly on the cellular concentration of sickle hemoglobin (Hb S). A possible therapeutic strategy for sickle cell disease is based on reducing the cellular concentration of Hb S through prevention of erythrocyte dehydration. The K-Cl cotransporter is a major determinant of sickle cell dehydration and is inhibited by increasing erythrocyte Mg content. We studied 10 patients with sickle cell disease before treatment and after 2 and 4 wk of treatment with oral Mg supplements (0.6 meq/kg/d Mg pidolate). Hematological parameters, erythrocyte Na, K, and Mg content, erythrocyte density, membrane transport of Na and K, and osmotic gradient ektacytometry were measured. We found significant increases in sickle erythrocyte Mg and K content and reduction in the number of dense sickle erythrocytes. Erythrocyte K-Cl cotransport was reduced significantly. We also observed a significant reduction in the absolute reticulocyte count and in the number of immature reticulocytes. Ektacytometric analysis showed changes indicative of improved hydration of the erythrocytes. There were no laboratory or clinical signs of hypermagnesemia. Mild, transient diarrhea was the only reported side effect. We conclude that oral Mg supplementation reduces the number of dense erythrocytes and improves the erythrocyte membrane transport abnormalities of patients with sickle cell disease.

Is resting state HCO3- secretion in frog gastric fundus mucosa mediated by apical Cl(-)-HCO3- exchange?

1. We have tested the widely accepted hypothesis that resting-state bicarbonate secretion of gastric fundus mucosa is mediated by Cl(-)-HCO3- exchange in the apical membrane of surface epithelial cells (SECs). To this end, SECs of isolated fundus mucosa of Rana esculenta were punctured with double-barrelled microelectrodes to measure intracellular pH (pHi). 2. No significant pHi changes were observed in response to changing luminal HCO3- and/or Cl- concentrations. The change in pHi (delta pHi) in response to luminal chloride substitution averaged 0.00 +/- 0.01 pH units (mean +/- S.E.M.; n = 48), and did not change after blocking putative basolateral acid/base transporters which could have masked the pHi response. 3. On the other hand, pHi responded readily and reversibly to luminal perfusion with either low-pH (pH 2.5) solution (delta pHi = -0.36 +/- 0.05; n = 4; P < 0.01) or CO2-free HCO3- Ringer solution (delta pHi = +0.10 +/- 0.01; n = 29; P < 0.001). These observations demonstrate that the solution change was effective and complete within 1 min and show that the apical membrane of SECs is permeable to CO2. 4. The apical membrane of frog SECs could not be stained with an antibody against the C-terminal end of the mouse Cl(-)-HCO3- exchanger isoform AE2, although this antibody readily stained the basolateral membrane of the oxyntopeptic cells (OCs). 5. In conclusion, the presence of a Cl(-)-HCO3- exchanger in the apical membrane of SECs of frog gastric fundus mucosa in the resting state could not be confirmed, but other models of HCO3- secretion cannot be fully excluded. Observations from electrical measurements, favouring a model of conductive HCO3- secretion, point to the OCs rather than the SECs as a site of origin of HCO3- secretion.

Role of adenosine nucleotides in the regulation of a stress-response transcription factor in Bacillus subtilis

The RNA polymerase sigma factor sigma B is a stress-response regulatory protein in Bacillus subtilis. The activity of sigma B is controlled in part by RsbW, a protein that inhibits sigma B, and RsbV, a protein that counteracts this inhibition. We now demonstrate that purified RsbW is capable of forming alternative complexes with either sigma B or RsbV. Sigma B in the RsbW. sigma B complex was transcriptionally inactive. RsbV reversed this inhibition by sequestering RsbW in a RsbW-RsbV complex, thereby allowing sigma B to remain free and active. In contrast to interactions among the components of the homologous regulatory system for the sporulation transcription factor sigma F, the binding of RsbW to RsbV and sigma B did not require adenosine nucleotides. Experiments involving the exchange of proteins between the two regulatory systems demonstrated that RsbW and its homolog in the sigma F system, SpoIIAB, exhibit strong preference in binding to RsbV and sigma B, and SpoIIAA and sigma F, respectively, and that the difference in nucleotide-dependence of binding between these two systems is attributable to a difference between RsbW and SpoIIAB. In confirmation and extension of previous results, we show that RsbW is also a protein kinase that uses ATP to phosphorylate RsbV, thereby blocking the capacity of RsbV to bind to RsbW and activate transcription. A close correlation was observed between the concentration of ATP required for efficient RsbW-mediated phosphorylation of RsbV, inhibition of RsbW.RsbV comlex formation, and inhibition of sigma B-directed transcription. These results are consistent with the hypothesis that activation of sigma B under certain stress condition is due to a decrease in cellular ATP levels.

SpoIIAA governs the release of the cell-type specific transcription factor sigma F from its anti-sigma factor SpoIIAB

The Bacillus subtilis transcription factor sigma F is a cell-type specific regulatory protein whose activity is governed by SpoIIAB and SpoIIAA and the nucleotides ATP and ADP. SpoIIAB is an anti-sigma factor that binds to sigma F in a manner that is stimulated by ATP, thereby trapping sigma F in an inactive complex. Alternatively, SpoIIAB binds to SpoIIAA in a manner that is stimulated by ADP to form a SpoIIAB.SpoIIAA complex in which SpoIIAB is sequestered from sigma F. SpoIIAB is also a protein kinase that uses ATP to phosphorylate, and thereby inactivate, SpoIIAA. Thus, ATP inhibits sigma F activity both by promoting formation of the SpoIIAB.sigma F complex and by phosphorylation of SpoIIAA. In extension of previous results, we use affinity chromatography to show that SpoIIAB is capable of forming long-lived complexes with sigma F and SpoIIAA and that the formation of these complexes is dependent on ATP and ADP, respectively. Using a DNA template lacking adenosine residues on the non-transcribed strand, we demonstrate that ATP is required for SpoIIAB-mediated inhibition of sigma F-directed RNA synthesis and that this inhibition is prevented by SpoIIAA in a manner that is stimulated by ADP. We show that ADP acts by protecting SpoIIAA from phosphorylation by SpoIIAB and that a mutant protein bearing an amino acid substitution at the site of phosphorylation in SpoIIAA is capable of preventing the inhibition of sigma F in a manner that does not depend on ADP. A principal finding from the investigation is that SpoIIAA restores activity to sigma F that had previously been inhibited by SpoIIAB. This is demonstrated both by the capacity of SpoIIAA to reverse SpoIIAB-mediated inhibition of sigma F-directed RNA synthesis and by its capacity to interact with and disrupt the SpoIIAB. sigma F complex. The results are consistent with a model in which sigma F is controlled by the cellular concentration of unphosphorylated SpoIIAA.

Subcellular localization of proteins governing the proteolytic activation of a developmental transcription factor in Bacillus subtilis

BACKGROUND

Spore formation in Bacillus subtilis takes place in a sporangium consisting of two compartments called the forespore and the mother cell. Late in development, when the forespore is wholly contained within the mother cell, gene transcription is coordinated between the compartments by an intercellular signal transduction pathway. This pathway operates at the level of proteolytic processing of the proprotein precursor (pro-sigma K to the mother-cell transcription factor sigma K. The conversion of pro-sigma K to sigma K is governed by the putative processing enzyme SpoIVFB and its negative regulator SpoIVFA, which are produced in the mother cell.

RESULTS

We used fluorescence microscopy in conjunction with antibodies against SpoIVFA and SpoIVFB and a fusion of SpoIVFB to the Green Fluorescent Protein from Aquorea victoria to visualize these proteins in the sporangium. Both proteins were found to co-localize with the forespore region of the sporangium, a finding consistent with the idea that SpoIVFA and SpoIVFB, which are inferred to be integral membrane proteins, are located in the mother cell membrane that surrounds the forespore.

CONCLUSIONS

We conclude that SpoIVFA and SpoIVFB are situated at the boundary between the forespore and the mother cell, at which location SpoIVFB could be activated by a signalling protein produced in the forespore.

SpoIIE governs the phosphorylation state of a protein regulating transcription factor sigma F during sporulation in Bacillus subtilis

Cell-specific activation of the transcription factor sigma F during sporulation in Bacillus subtilis is controlled by a regulatory pathway involving the proteins SpoIIE, SpoIIAA, and SpoIIAB. SpoIIAB is an antagonist of sigma F, and SpoIIAA, which is capable of overcoming SpoIIAB-mediated inhibition of sigma F, is an antagonist of SpoIIAB. SpoIIAA is, in turn, negatively regulated by SpoIIAB, which phosphorylates SpoIIAA on serine 58. SpoIIAA is also positively regulated by SpoIIE, which dephosphorylates SpoIIAA-P, the phosphorylated form of SpoIIAA. Here, isoelectric focusing and Western blot analysis were used to examine the phosphorylation state of SpoIIAA in vivo. SpoIIAA was found to be largely in the phosphorylated state during sporulation in wild-type cells but a significant portion of the protein that was unphosphorylated could also be detected. Consistent with the idea that SpoIIE governs dephosphorylation of SpoIIAA-P, SpoIIAA was entirely in the phosphorylated state in spoIIE mutant cells. Conversely, overexpression of spoIIE led to an increase in the ratio of unphosphorylated SpoIIAA to SpoIIAA-P and caused inappropriate activation of sigma F in the predivisional sporangium. We also show that a mutant form of SpoIIAA (SpoIIAA-S58T) in which serine 58 was replaced with threonine was present exclusively as SpoIIAA-P, a finding that confirms previous biochemical evidence that the mutant protein is an effective substrate for the SpoIIAB kinase but that SpoIIAA-S58T-P cannot be dephosphorylated by SpoIIE. We conclude that SpoIIE plays a crucial role in controlling the phosphorylation state of SpoIIAA during sporulation and thus in governing the cell-specific activation of sigma F.

Antigen retrieval in cryostat tissue sections and cultured cells by treatment with sodium dodecyl sulfate (SDS)

A simple method for antigen retrieval in tissue sections and cell cultures is described. Because many antibodies recognize denatured proteins on western blots, but are poorly reactive by immunocytochemistry, the effect of applying sodium dodecyl sulfate (SDS) to cryostat sections of tissues and to cell cultures prior to immunostaining was examined. In many cases, a 5-min pretreatment with 1% SDS produced a dramatic increase in staining intensity by indirect immunofluorescence. Among the antibodies tested that showed a positive effect of SDS were an anti-Na/K-ATPase monoclonal antibody, an anti-AE1/2 anion exchanger polyclonal antipeptide antibody, a monoclonal anti-caveolin antibody, and an anti-rab4 monoclonal antibody. In other cases, including antibodies against gp330, aquaporin 1, and aquaporin 2, no effect of SDS was detected. The results show that SDS treatment can be used as a simple method of antigen retrieval in cryostat sections and on cultured cells. In some cases, antigens were not detectable without pretreatment with SDS.

Activation of cell-specific transcription by a serine phosphatase at the site of asymmetric division

Cell fate is determined by cell-specific activation of transcription factor sigma F after asymmetric division during sporulation by Bacillus subtilis. The activity of sigma F is governed by SpoIIAA, SpoIIAB, and SpoIIE, a membrane protein localized at the polar septum. SpoIIAB binds to and inhibits sigma F, and SpoIIAA inhibits SpoIIAB, which prevents SpoIIAB from binding to sigma F. SpoIIAB is also a serine kinase that inactivates SpoIIAA. Here, it is demonstrated that SpoIIE dephosphorylates SpoIIAA-P and overcomes SpoIIAB-mediated inhibition of sigma F. The finding that SpoIIE is a serine phosphatase links asymmetric division to the pathway governing cell-specific gene transcription.

Establishment of cell type specific gene transcription during sporulation in Bacillus subtilis

Asymmetric cell division during the process of sporulation in the bacterium Bacillus subtilis generates dissimilar progeny that exhibit distinct programs of gene transcription. Recent work reveals a partner switching mechanism that governs the activity of the sporulation regulatory protein sigma F and that may be responsible for the establishment of cell type specific gene transcription.

Reducing disruptive behaviors by training students to request assistance

Disruptive behaviors of students with disabilities can have a communicative function. They may aid the learner in escaping from aversive situations, and they may also serve to produce positive events. Disruptive behaviors that have a communicative function may be eliminated by teaching an alternative prosocial response. This study compared the relative effectiveness of two teaching methods for reducing disruptive behaviors exhibited by two primary age students with moderate disabilities. The first method consisted solely of a hierarchy of prompts. The second method combined the prompting hierarchy with a cue to request assistance. A multiple baseline design across students with alternating treatments was used to evaluate performance. Results demonstrated a clear relationship between teaching participants to request assistance and a reduction in disruptive behaviors.

Allergy to sodium hypochlorite during root canal therapy: a case report

Sodium hypochlorite (NaOCl), is the most popular irrigation solution used in root canal treatment but it is known to be an irritant to vital tissues. There have been many case reports dealing with toxic effects of this material. Although the allergic potential of NaOCl has been described in the medical literature, only one case of known hypersensitivity to NaOCl has been reported in the dental literature. In this paper a case is presented, describing both local and systemic adverse tissue reactions, caused by an allergic response, after NaOCl irrigation.

An adenosine nucleotide switch controlling the activity of a cell type-specific transcription factor in B. subtilis

The sigma F factor establishes cell type-specific gene transcription during sporulation in B. subtilis. sigma F is negatively regulated by SpollAB, which forms complexes with sigma F or SpollAA. ATP and its nonhydrolyzable analogs stimulate the formation of the SpollAB.sigma F complex, whereas ADP stimulates the formation of the SpollAB.SpollAA complex. Which protein SpollAB associates with is determined by the concentrations of the two nucleotides, on which basis we propose a partner-switching model for the regulation of sigma F: [formula: see text] Consistent with this model, SpollAA reverses SpollAB-mediated inhibition of sigma F-directed transcription in a manner that depends on ADP. Cell-specific activation of sigma F could be due to an alteration in adenosine nucleotide levels in one cell of the sporangium.

Using self-recording, evaluation, and graphing to increase completion of homework assignments

This article describes the use of self-monitoring procedures to increase the number of daily homework assignments completed by eight students with learning disabilities. Students ranged in age from 13 to 16 years and attended Grades 7 through 10. The experimental procedure involved the use of a sheet listing all daily assignments given by regular classroom teachers. A multiple-baseline design across subjects demonstrated a clear relationship between the introduction of self-monitoring of assignments and an increase in assignments completed. Goal setting and self-graphing of data appeared to increase this effect.

Duplication of 10 nucleotides in the erythroid band 3 (AE1) gene in a kindred with hereditary spherocytosis and band 3 protein deficiency (band 3PRAGUE)

We describe a duplication of 10 nucleotides (2,455-2,464) in the band 3 gene in a kindred with autosomal dominant hereditary spherocytosis and a partial deficiency of the band 3 protein that is reflected by decreased rate of transmembrane sulfate flux and decreased density of intramembrane particles. The mutant allele potentially encodes an abnormal band 3 protein with a 3.5-kD COOH-terminal truncation; however, we did not detect the mutant protein in the membrane of mature red blood cells. Since the mRNA levels for the mutant and normal alleles are similar and since the band 3 content is the same in the light and dense red cell fractions, we conclude that the mutant band 3 is either not inserted into the plasma membrane or lost from the membrane prior to the release of red blood cells into circulation. We further show that the decrease in band 3 content principally involves the dimeric laterally and rotationally mobile fraction of the band 3 protein, while the laterally immobile and rotationally restricted band 3 fraction is left essentially intact. We propose that the decreased density of intramembrane particles decreases the stability of the membrane lipid bilayer and causes release of lipid microvesicles that leads to surface area deficiency and spherocytosis.

Extended school year programs: a community-driven curriculum model

Appropriate education guaranteed to children with disabilities under P.L. 94-142 has been translated by the courts to mean more than 180 days of education. There is now a strong legal precedent establishing the right to an extended school year (summer school) for students with severe disabilities. The courts have left open to interpretation, however, issues related to the program implementation. Descriptions of extended school year programs vary widely and include respite for parents, continuation of the regular school year curriculum, and remediation in skill areas. The only consensus seems to be that these programs should be tailored to individual needs. In the present article a systematic approach to curriculum development for students with severe disabilities enrolled in extended school year programs was described. This approach is (a) community driven, (b) consistent with each student's IEP objectives for the regular school year, (c) tailored to the individual student, and (d) consistent with current best practices of teaching functional skills performed by individuals without disabilities in a variety of integrated nonschool settings. Student progress data were presented.