Microbial complexes in subgingival plaque

It has been recognized for some time that bacterial species exist in complexes in subgingival plaque. The purpose of the present investigation was to attempt to define such communities using data from large numbers of plaque samples and different clustering and ordination techniques. Subgingival plaque samples were taken from the mesial aspect of each tooth in 185 subjects (mean age 51 +/- 16 years) with (n = 160) or without (n = 25) periodontitis. The presence and levels of 40 subgingival taxa were determined in 13,261 plaque samples using whole genomic DNA probes and checkerboard DNA-DNA hybridization. Clinical assessments were made at 6 sites per tooth at each visit. Similarities between pairs of species were computed using phi coefficients and species clustered using an averaged unweighted linkage sort. Community ordination was performed using principal components analysis and correspondence analysis. 5 major complexes were consistently observed using any of the analytical methods. One complex consisted of the tightly related group: Bacteroides forsythus, Porphyromonas gingivalis and Treponema denticola. The 2nd complex consisted of a tightly related core group including members of the Fusobacterium nucleatum/periodonticum subspecies, Prevotella intermedia, Prevotella nigrescens and Peptostreptococcus micros. Species associated with this group included: Eubacterium nodatum, Campylobacter rectus, Campylobacter showae, Streptococcus constellatus and Campylobacter gracilis. The 3rd complex consisted of Streptococcus sanguis, S. oralis, S. mitis, S. gordonii and S. intermedius. The 4th complex was comprised of 3 Capnocytophaga species, Campylobacter concisus, Eikenella corrodens and Actinobacillus actinomycetemcomitans serotype a. The 5th complex consisted of Veillonella parvula and Actinomyces odontolyticus. A. actinomycetemcomitans serotype b, Selenomonas noxia and Actinomyces naeslundii genospecies 2 (A. viscosus) were outliers with little relation to each other and the 5 major complexes. The 1st complex related strikingly to clinical measures of periodontal disease particularly pocket depth and bleeding on probing.

Tumoricidal activity of tumor necrosis factor-related apoptosis-inducing ligand in vivo

To evaluate the utility of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) as a cancer therapeutic, we created leucine zipper (LZ) forms of human (hu) and murine (mu) TRAIL to promote and stabilize the formation of trimers. Both were biologically active, inducing apoptosis of both human and murine target cells in vitro with similar specific activities. In contrast to the fulminant hepatotoxicity of LZ-huCD95L in vivo, administration of either LZ-huTRAIL or LZ-muTRAIL did not seem toxic to normal tissues of mice. Finally, repeated treatments with LZ-huTRAIL actively suppressed growth of the TRAIL-sensitive human mammary adenocarcinoma cell line MDA-231 in CB.17 (SCID) mice, and histologic examination of tumors from SCID mice treated with LZ-huTRAIL demonstrated clear areas of apoptotic necrosis within 9-12 hours of injection.

Sexual abuse in a national survey of adult men and women: prevalence, characteristics, and risk factors

This paper reports on the first national survey of adults concerning a history of childhood sexual abuse. Victimization was reported by 27% of the women and 16% of the men. Higher rates of abuse were found among men who grew up in unhappy families, lived for some period with only their mothers, who were currently residing in the West and who came from English or Scandinavian heritage. Higher rates of abuse were found among women who grew up in unhappy families, lived for some period without one of their natural parents, received inadequate sex education, were currently residing in the West or who were born after 1925.

Imaging beta-amyloid burden in aging and dementia

OBJECTIVE

To compare brain beta-amyloid (Abeta) burden measured with [(11)C]Pittsburgh Compound B (PIB) PET in normal aging, Alzheimer disease (AD), and other dementias.

METHODS

Thirty-three subjects with dementia (17 AD, 10 dementia with Lewy bodies [DLB], 6 frontotemporal dementia [FTD]), 9 subjects with mild cognitive impairment (MCI), and 27 age-matched healthy control subjects (HCs) were studied. Abeta burden was quantified using PIB distribution volume ratio.

RESULTS

Cortical PIB binding was markedly elevated in every AD subject regardless of disease severity, generally lower and more variable in DLB, and absent in FTD, whereas subjects with MCI presented either an "AD-like" (60%) or normal pattern. Binding was greatest in the precuneus/posterior cingulate, frontal cortex, and caudate nuclei, followed by lateral temporal and parietal cortex. Six HCs (22%) showed cortical uptake despite normal neuropsychological scores. PIB binding did not correlate with dementia severity in AD or DLB but was higher in subjects with an APOE-epsilon4 allele. In DLB, binding correlated inversely with the interval from onset of cognitive impairment to diagnosis.

CONCLUSIONS

Pittsburgh Compound B PET findings match histopathologic reports of beta-amyloid (Abeta) distribution in aging and dementia. Noninvasive longitudinal studies to better understand the role of amyloid deposition in the course of neurodegeneration and to determine if Abeta deposition in nondemented subjects is preclinical AD are now feasible. Our findings also suggest that Abeta may influence the development of dementia with Lewy bodies, and therefore strategies to reduce Abeta may benefit this condition.

Placental blood as a source of hematopoietic stem cells for transplantation into unrelated recipients

BACKGROUND

Transplantation of bone marrow from unrelated donors is limited by a lack of HLA-matched donors and the risk of graft-versus-host disease (GVHD). Placental blood from sibling donors can reconstitute hematopoiesis. We report preliminary results of transplantation using partially HLA-mismatched placental blood from unrelated donors.

METHODS

Twenty-five consecutive patients, primarily children, with a variety of malignant and non-malignant conditions received placental blood from unrelated donors and were evaluated for hematologic and immunologic reconstitution and GVHD. HLA matching was performed before transplantation by serologic typing for class I HLA antigens and low-resolution molecular typing for class II HLA alleles. In donor-recipient pairs who differed by no more than one HLA antigen or allele, high-resolution class II HLA typing was done retrospectively. Fordonor-recipient pairs who were mismatched for two HLA antigens or alleles, high-resolution typing was used prospectively to select the best match for HLA-DRB1.

RESULTS

Twenty-four of the 25 donor-recipient pairs were discordant for one to three HLA antigens. In 23 of the 25 transplant recipients, the infused hematopoletic stem cells engrafted. Acute grade III GVHD occurred in 2 of the 21 patients who could be evaluated, and 2 patients had chronic GVHD. In vitro proliferative responses of T cells and B cells to plant mitogens were detected 60 days after transplantation. With a median follow-up of 12 1/2 months and a minimal follow-up of 100 days, the overall 100-day survival rate among these patients was 64 percent, and the overall event-free survival was 48 percent.

CONCLUSIONS

HLA-mismatched placental blood from unrelated donors is an alternative source of stem cells for hematopoietic reconstitution in children.

Kinetics of superoxide dismutase- and iron-catalyzed nitration of phenolics by peroxynitrite

Superoxide dismutase and Fe3+EDTA catalyzed the nitration by peroxynitrite (ONOO-) of a wide range of phenolics including tyrosine in proteins. Nitration was not mediated by a free radical mechanism because hydroxyl radical scavengers did not reduce either superoxide dismutase or Fe3+EDTA-catalyzed nitration and nitrogen dioxide was not a significant product from either catalyst. Rather, metal ions appear to catalyze the heterolytic cleavage of peroxynitrite to form a nitronium-like species (NO2+). The calculated energy for separating peroxynitrous acid into hydroxide ion and nitronium ion is 13 kcal.mol-1 at pH 7.0. Fe3+EDTA catalyzed nitration with an activation energy of 12 kcal.mol-1 at a rate of 5700 M-1.s-1 at 37 degrees C and pH 7.5. The reaction rate of peroxynitrite with bovine Cu,Zn superoxide dismutase was 10(5) M-1.s-1 at low superoxide dismutase concentrations, but the rate of nitration became independent of superoxide dismutase concentration above 10 microM with only 9% of added peroxynitrite yielding nitrophenol. We propose that peroxynitrite anion is more stable in the cis conformation, whereas only a higher energy species in the trans conformation can fit in the active site of Cu,Zn superoxide dismutase. At high superoxide dismutase concentrations, phenolic nitration may be limited by the rate of isomerization from the cis to trans conformations of peroxynitrite as well as by competing pathways for peroxynitrite decomposition. In contrast, Fe3+EDTA appears to react directly with the cis anion, resulting in greater nitration yields.

Definition of treatment goals for moderate to severe psoriasis: a European consensus

Patients with moderate to severe psoriasis are undertreated. To solve this persistent problem, the consensus programme was performed to define goals for treatment of plaque psoriasis with systemic therapy and to improve patient care. An expert consensus meeting and a collaborative Delphi procedure were carried out. Nineteen dermatologists from different European countries met for a face-to-face discussion and defined items through a four-round Delphi process. Severity of plaque psoriasis was graded into mild and moderate to severe disease. Mild disease was defined as body surface area (BSA) ≤10 and psoriasis area and severity index (PASI) ≤10 and dermatology life quality index (DLQI) ≤10 and moderate to severe psoriasis as (BSA > 10 or PASI > 10) and DLQI > 10. Special clinical situations may change mild psoriasis to moderate to severe including involvement of visible areas or severe nail involvement. For systemic therapy of plaque psoriasis two treatment phases were defined: (1) induction phase as the treatment period until week 16; however, depending on the type of drug and dose regimen used, this phase may be extended until week 24 and (2) maintenance phase for all drugs was defined as the treatment period after the induction phase. For the definition of treatment goals in plaque psoriasis, the change of PASI from baseline until the time of evaluation (ΔPASI) and the absolute DLQI were used. After induction and during maintenance therapy, treatment can be continued if reduction in PASI is ≥75%. The treatment regimen should be modified if improvement of PASI is <50%. In a situation where the therapeutic response improved ≥50% but <75%, as assessed by PASI, therapy should be modified if the DLQI is >5 but can be continued if the DLQI is ≤5. This programme defines the severity of plaque psoriasis for the first time using a formal consensus of 19 European experts. In addition, treatment goals for moderate to severe disease were established. Implementation of treatment goals in the daily management of psoriasis will improve patient care and mitigate the problem of undertreatment. It is planned to evaluate the implementation of these treatment goals in a subsequent programme involving patients and physicians.

Experience-dependent changes in cerebral activation during human REM sleep

The function of rapid-eye-movement (REM) sleep is still unknown. One prevailing hypothesis suggests that REM sleep is important in processing memory traces. Here, using positron emission tomography (PET) and regional cerebral blood flow measurements, we show that waking experience influences regional brain activity during subsequent sleep. Several brain areas activated during the execution of a serial reaction time task during wakefulness were significantly more active during REM sleep in subjects previously trained on the task than in non-trained subjects. These results support the hypothesis that memory traces are processed during REM sleep in humans.

Isolation of primitive human hematopoietic progenitors on the basis of aldehyde dehydrogenase activity

Because hematopoietic stem cells are rich in aldehyde dehydrogenase (ALDH) activity, we developed a fluorescent substrate for ALDH, termed BODIPY aminoacetaldehyde (BAAA), and tested its potential for isolating primitive human hematopoietic cells. A population of cells with low orthogonal light scattering and bright fluorescence intensity (SSC(lo)ALDH(br) cells) could be readily fractionated from human umbilical cord blood cells costained with BAAA and the multidrug-resistance inhibitor verapamil. The SSC(lo)ALDH(br) population was depleted of lineage-committed cells, 40-90% pure for CD34(+)CD38(lo/-) cells, and enriched 50- to 100-fold for primitive hematopoietic progenitors detected in short- and long-term culture analyses. Together, these observations indicate that fractionating human hematopoietic stem cells on the basis of ALDH activity using BAAA is an effective method for isolating primitive human hematopoietic progenitors. This technique may be useful for isolating stem cells from other tissues as well.

Isolation and characterization of a mouse interleukin cDNA clone that expresses B-cell stimulatory factor 1 activities and T-cell- and mast-cell-stimulating activities

A cDNA sequence coding for a unique mouse interleukin that expresses B-cell-, T-cell, and mast-cell-stimulating activities has been isolated from a mouse helper T-cell cDNA library. The library, constructed in the pcD expression vector, was screened by transfecting COS monkey cells with DNA pools to express the products encoded by full-length cDNA inserts. By assaying the transfected cell supernatants, we identified clones encoding a factor that stimulates T-cell and mast cell lines. This factor also induces Ia expression on resting B cells and enhances IgG1 and IgE production by B cells, two properties of B-cell-stimulatory factor 1. The DNA sequence codes for a polypeptide of 140 amino acid residues including a putative signal peptide. These results demonstrate that a single cDNA clone distinct from interleukin 2 and interleukin 3 encodes a polypeptide with multiple biological activities.

Golgi tubule traffic and the effects of brefeldin A visualized in living cells

The Golgi complex is a dynamic organelle engaged in both secretory and retrograde membrane traffic. Here, we use green fluorescent protein-Golgi protein chimeras to study Golgi morphology in vivo. In untreated cells, membrane tubules were a ubiquitous, prominent feature of the Golgi complex, serving both to interconnect adjacent Golgi elements and to carry membrane outward along microtubules after detaching from stable Golgi structures. Brefeldin A treatment, which reversibly disassembles the Golgi complex, accentuated tubule formation without tubule detachment. A tubule network extending throughout the cytoplasm was quickly generated and persisted for 5-10 min until rapidly emptying Golgi contents into the ER within 15-30 s. Both lipid and protein emptied from the Golgi at similar rapid rates, leaving no Golgi structure behind, indicating that Golgi membranes do not simply mix but are absorbed into the ER in BFA-treated cells. The directionality of redistribution implied Golgi membranes are at a higher free energy state than ER membranes. Analysis of its kinetics suggested a mechanism that is analogous to wetting or adsorptive phenomena in which a tension-driven membrane flow supplements diffusive transfer of Golgi membrane into the ER. Such nonselective, flow-assisted transport of Golgi membranes into ER suggests that mechanisms that regulate retrograde tubule formation and detachment from the Golgi complex are integral to the existence and maintenance of this organelle.

Stimulation of lipid peroxidation and hydroxyl-radical generation by the contents of human atherosclerotic lesions

Lipid peroxidation within human arterial lesions is thought to play an important role in the development of atherosclerosis. Peroxidation can be accelerated by the presence of 'catalytic' iron or copper ions. Gruel samples from advanced atherosclerotic lesions in the abdominal aortae of human cadavers were tested for pro-oxidant properties. All samples contained bleomycin-detectable iron and phenanthroline-detectable copper. Almost all gruel samples stimulated peroxidation of rat liver microsomes, and this was usually inhibited by the iron-ion chelator desferrioxamine. Some samples stimulated formation of hydroxyl radicals from H2O2 in the presence of ascorbate, a reaction again inhibited by desferrioxamine. We conclude that the interior of human advanced atherosclerotic lesions is a highly pro-oxidant environment, and that the use of copper or iron ions to promote peroxidation of low-density lipoproteins in vitro may be a valid model for events in the arterial wall.

Effects of fat on insulin-stimulated carbohydrate metabolism in normal men

We have examined the onset and duration of the inhibitory effect of an intravenous infusion of lipid/heparin on total body carbohydrate and fat oxidation (by indirect calorimetry) and on glucose disappearance (with 6,6 D2-glucose and gas chromatography-mass spectrometry) in healthy men during euglycemic hyperinsulinemia. Glycogen synthase activity and concentrations of acetyl-CoA, free CoA-SH, citrate, and glucose-6-phosphate were measured in muscle biopsies obtained before and after insulin/lipid and insulin/saline infusions. Lipid increased insulin-inhibited fat oxidation (+40%) and decreased insulin-stimulated carbohydrate oxidation (-63%) within 1 h. These changes were associated with an increase (+489%) in the muscle acetyl-CoA/free CoA-SH ratio. Glucose disappearance did not decrease until 2-4 h later (-55%). This decrease was associated with a decrease in muscle glycogen synthase fractional velocity (-82%). The muscle content of citrate and glucose-6-phosphate did not change. We concluded that, during hyperinsulinemia, lipid promptly replaced carbohydrate as fuel for oxidation in muscle and hours later inhibited glucose uptake, presumably by interfering with muscle glycogen formation.

The effect of SRP on the clinical and microbiological parameters of periodontal diseases

The purpose of the present investigation was to examine the effect of SRP on clinical and microbiological parameters in 57 subjects with adult periodontitis (mean age 47 +/- 11 years). Subjects were monitored clinically and microbiologically prior to and 3, 6 and 9 months after full-mouth SRP under local anaesthesia. Clinical assessments of plaque, redness, suppuration, BOP, pocket depth and attachment level were made at 6 sites per tooth. The means of duplicate attachment level measurements taken at each visit were used to assess change between visits. Clinical data were averaged within each subject and then averaged across subjects for each visit. Subgingival plaque samples were taken from the mesial aspect of each tooth and the presence and levels of 40 subgingival taxa were determined using whole genomic DNA probes and checkerboard DNA-DNA hybridization. The mean levels and % of sites colonized by each species (prevalence) was computed for each subject at each visit. Differences in clinical and microbiological parameters before and after SRP were sought using the Wilcoxon signed ranks test or the Quade test for more than 2 visits. Overall, there was a mean gain in attachment level of 0.11 +/- 0.23 mm (range -0.53 to 0.64 mm) 3 months post-therapy. There was a significant decrease in the % of sites exhibiting gingival redness (68 to 57%) and BOP (58 to 52%) as well as a mean (+/-SEM) pocket depth (3.3 +/- 0.06 to 3.1 +/- 0.05 mm). Sites with pre-therapy pocket depths of < 4 mm showed a non-significant increase in pocket depth and attachment level, 4.6 mm pockets showed a significant decrease in pocket depth and a non-significant gain in attachment post-therapy, while > 6 mm pockets showed a significant decrease in pocket depth and attachment level measurements post-therapy. Significant clinical improvements were seen in subjects who had never smoked or were past smokers but not in current smokers. Mean prevalences and levels of P. gingivalis, T. denticola and B. forsythus were significantly reduced after SRP, while A. viscosus showed a significant increase in mean levels. The mean decrease in prevalence of P. gingivalis was similar at all pocket depth categories, while B. forsythus decreased more at shallow and intermediate pockets and A. viscosus increased most at deep sites. P. gingivalis. B. forsythus and T. denticola were equally prevalent among current, past and never smokers pre-therapy, decreased significantly post-SRP in never and past smokers but increased in current smokers. Clinical improvement post-SRP was accompanied by a modest change in the subgingival microbiota, primarily a reduction in P. gingivalis, B. forsythus and T. denticola, suggesting potential targets for therapy and indicating that radical alterations in the subgingival microbiota may not be necessary or desirable in many patients.

Crystal structure of the breakage-reunion domain of DNA gyrase

DNA gyrase is a type II DNA topoisomerase from bacteria that introduces supercoils into DNA. It catalyses the breakage of a DNA duplex (the G segment), the passage of another segment (the T segment) through the break, and then the reunification of the break. This activity involves the opening and dosing of a series of molecular 'gates' which is coupled to ATP hydrolysis. Here we present the crystal structure of the 'breakage-reunion' domain of the gyrase at 2.8 A resolution. Comparison of the structure of this 59K (relative molecular mass, 59,000) domain with that of a 92K fragment of yeast topoisomerase II reveals a very different quaternary organization, and we propose that the two structures represent two principal conformations that participate in the enzymatic pathway. The gyrase structure reveals a new dimer contact with a grooved concave surface for binding the G segment and a cluster of conserved charged residues surrounding the active-site tyrosines. It also shows how breakage of the G segment can occur and, together with the topoisomerase II structure, suggests a pathway by which the T segment can be released through the second gate of the enzyme. Mutations that confer resistance to the quinolone antibacterial agents cluster at the new dimer interface, indicating how these drugs might interact with the gyrase-DNA complex.

Efficacy and safety of pegylated (40-kd) interferon alpha-2a compared with interferon alpha-2a in noncirrhotic patients with chronic hepatitis C

Administration of interferon (IFN) 3 times weekly in patients with chronic hepatitis C (CHC) is associated with low sustained responses, which may be, in part, related to this regimen's inability to maintain IFN concentrations sufficient to suppress viral replication. An enhanced IFN molecule produced by the covalent attachment of a branched 40-kd polyethylene glycol moiety to IFN alpha-2a (PEG[40kd] IFN alpha-2a) exhibits sustained absorption, a restricted volume of distribution, and reduced clearance compared with unmodified IFN alpha-2a. One hundred fifty-nine patients with CHC participated in a randomized, ascending-dose (45 or 90, 180, 270 microg) study comparing PEG(40kd) IFN alpha-2a administered once weekly with 3 MIU IFN alpha-2a administered 3 times weekly for 48 weeks to determine the most appropriate PEG(40kd) IFN alpha-2a dose for subsequent clinical trials. Efficacy was assessed by measuring hepatitis C virus (HCV) RNA following a 24-week treatment-free period. Sustained virological responses for PEG(40kd) IFN alpha-2a once weekly were 10% (45 microg; not significant), 30% (90 microg; P = .009), 36% (180 microg; P = .0006), and 29% (270 microg; P = .004), compared with 3% for the 3-times-weekly 3-MIU IFN alpha-2a regimen. The types and frequencies of adverse events and laboratory abnormalities were similar among all groups. In conclusion, once-weekly PEG(40kd) IFN alpha-2a was associated with a higher number of sustained virological responses compared with IFN alpha-2a 3 times weekly in patients with CHC, but had a similar safety profile. The 180-microg PEG(40kd) IFN alpha-2a dose appeared to be the optimal dose based on sustained virological response and its associated side-effect profile.

Sleep states and memory processes

Evidence for the involvement of rapid eye movement (REM) sleep or paradoxical sleep (PS) with memory processing continues to accumulate. In animals, there is continuing evidence of relatively small, vulnerable paradoxical sleep windows (PSWs) following successful acquisition. These PSWs, which manifest as increases in PS over normal levels, appear to exhibit shorter latencies to onset when the amount of material presented during acquisition is increased. Prevention of the PSW results in memory deficits. In humans, there is now evidence that different types of tasks are differentially sensitive to rapid eye movement sleep deprivation (REMD). Memory for declarative or explicit types of tasks appear not to be affected by REM sleep loss, while memory for cognitive procedural or implicit types of material are impaired by REMD. Using post training auditory stimulation during REM sleep, memory enhancement of the procedural material is also possible. The memory for a fine motor task appears to be sensitive to post training stage 2 sleep loss. The important neural structures are generally not yet identifiable, although the hippocampus would appear to be important for place learning in the Morris water maze.

Chronic myeloid leukemia stem cells possess multiple unique features of resistance to BCR-ABL targeted therapies

The leukemic stem cells in patients with chronic myeloid leukemia (CML) are well known to be clinically resistant to conventional chemotherapy and may also be relatively resistant to BCR-ABL-targeted drugs. Here we show that the lesser effect of imatinib mesylate (IM) on the 3-week output of cells produced in vitro from lin(-)CD34(+)CD38(-) CML (stem) cells compared with cultures initiated with the CD38(+) subset of lin(-)CD34(+) cells is markedly enhanced (>10-fold) when conditions of reduced growth factor stimulation are used. Quantitative analysis of genes expressed in these different CML subsets revealed a differentiation-associated decrease in IL-3 and G-CSF transcripts, a much more profound decrease in expression of BCR-ABL than predicted by changes in BCR expression, decreasing expression of ABCB1/MDR and ABCG2 and increasing expression of OCT1. p210(BCR-ABL) and kinase activity were also higher in the lin(-)CD34(+)CD38(-) cells and formal evidence that increasing BCR-ABL expression decreases IM sensitivity was obtained from experiments with a cell line model. Nevertheless, within the entire CD34(+) subset of CML cells, BCR-ABL expression was not strongly affected by changes in cell cycle status. Taken together, these results provide the first evidence of multiple mechanisms of innate IM resistance in primitive and quiescent CML cells.

European consensus statement on phenotypes of pustular psoriasis

Pustular psoriasis (PP) is a group of inflammatory skin conditions characterized by infiltration of neutrophil granulocytes in the epidermis to such an extent that clinically visible sterile pustules develop. Because of clinical co-incidence, PP is currently grouped with psoriasis vulgaris (PV). However, PP and PV are phenotypically different, respond differently to treatments and seem to be distinct on the genetic level. In contrast to PV, the phenotypes of PP are not well defined. Descriptions of each form of PP are discordant among standard dermatology textbooks [Saurat Dermatologie 2016, Rook's Dermatology 2016, Fitzpatrick's 2012 and Braun-Falco 2012], encumbering the collection of phenotypically well-matched groups of patients as well as clinical trials. The European Rare and Severe Psoriasis Expert Network (ERASPEN) was founded to define consensus criteria for diagnosis, deeply phenotype large groups of PP patients, analyse the genetics and pathophysiology and prepare for prospective clinical trials. This work reviews historical aspects of these conditions, new genetic findings and presents our initial considerations on the phenotypes of PP and a consensus classification of clinical phenotypes that will be used as a baseline for further, prospective studies of PP. Generalized pustular psoriasis (GPP) is defined as primary, sterile, macroscopically visible pustules on non-acral skin (excluding cases where pustulation is restricted to psoriatic plaques). GPP can occur with or without systemic inflammation, with or without PV and can either be a relapsing (>1 episode) or persistent (>3 months) condition. Acrodermatitis continua of Hallopeau (ACH) is characterized by primary, persistent (>3 months), sterile, macroscopically visible pustules affecting the nail apparatus. Palmoplantar pustulosis (PPP) has primary, persistent (>3 months), sterile, macroscopically visible pustules on palms and/or soles and can occur with or without PV.

Compartmentation of glutathione: implications for the study of toxicity and disease

The fact that glutathione (GSH) plays many roles in biological protective mechanisms and critical physiological functions has been recognized for decades. Conjugates, disulfides, and other glutathione-derived products also have been studied as biomarkers of the chemical natures or specific identities of key metabolites of toxic agents and such studies have been crucial in the delineation of the nature of the interactions of proximal toxicants with target biomolecules. Despite the extensive evidence implicating the depletion and/or oxidation of glutathione in a wide variety of human and experimental toxicities, critical examination of such studies frequently reveals that injury is not simply related to glutathione status. GSH is compartmentalized at several levels and this compartmentation appears to exert considerable influence on the relationships between glutathione depletion or oxidation and the onset of injury. Although compartmentation is usually viewed from the perspective of different intracellular pools, the significance of extracellular glutathione in functionally important pools is gaining recognition. As the factors affecting the interactions of intracellular pools with extracellular pools are delineated, studies in humans can be designed and interpreted with greater precision and utility.

Impaired sucrose-induction mutants reveal the modulation of sugar-induced starch biosynthetic gene expression by abscisic acid signalling

Plants both produce and utilize carbohydrates and have developed mechanisms to regulate their sugar status and co-ordinate carbohydrate partitioning. High sugar levels result in a feedback inhibition of photosynthesis and an induction of storage processes. We used a genetic approach to isolate components of the signalling pathway regulating the induction of starch biosynthesis. The regulatory sequences of the sugar inducible ADP-glucose pyrophosphorylase subunit ApL3 were fused to a negative selection marker. Of the four impaired sucrose induction (isi) mutants described here, two (isi1 and isi2) were specific to this screen. The other two mutants (isi3 and isi4) showed additional phenotypes associated with sugar-sensing screens that select for seedling establishment on high-sugar media. The isi3 and isi4 mutants were found to be involved in the abscisic acid signalling pathway. isi3 is allelic to abscisic acid insensitive4 (abi4), a gene encoding an Apetala2-type transcription factor; isi4 was found to be allelic to glucose insensitive1 (gin1) previously reported to reveal cross-talk between ethylene and glucose signalling. Here we present an alternative interpretation of gin1 as an allele of the ABA-deficient mutant aba2. Expression analysis showed that ABA is unable to induce ApL3 gene expression by itself, but greatly enhances ApL3 induction by sugar. Our data suggest a major role for ABA in relation to sugar-signalling pathways, in that it enhances the ability of tissues to respond to subsequent sugar signals.